ci(ios): strip CRLF from ffmpeg plugin scripts before pod install

The ffmpeg_kit_flutter_new_full pub package ships setup_ios.sh with CRLF line endings, so its podspec prepare_command failed with '/bin/bash^M: bad interpreter'. Normalize the plugin's shell scripts in the pub cache before building iOS.

.github/workflows/release.yml

@@ -257,6 +257,15 @@ jobs:
       - name: Get Flutter dependencies
         run: flutter pub get
 
+      - name: Normalize ffmpeg plugin shell scripts (strip CRLF)
+        run: |
+          find "$HOME/.pub-cache/hosted" -path "*ffmpeg_kit_flutter_new_full*/scripts/*.sh" -type f -print0 |
+            while IFS= read -r -d '' f; do
+              perl -pi -e 's/\r$//' "$f"
+              chmod +x "$f"
+              echo "Normalized line endings: $f"
+            done
+
       - name: Generate app icons
         run: dart run flutter_launcher_icons
 

.gitignore

@@ -44,6 +44,7 @@ go_backend/*.xcframework/
 # Android
 android/.gradle/
 android/app/libs/gobackend.aar
+android/app/libs/gobackend-sources.jar
 android/local.properties
 android/*.iml
 android/key.properties
@@ -57,7 +58,6 @@ ios/Pods/
 ios/.symlinks/
 ios/Flutter/Flutter.framework/
 ios/Flutter/Flutter.podspec
-android/app/libs/gobackend-sources.jar
 
 # Extension folder
 extension/
@@ -66,8 +66,12 @@ extension/
 AGENTS.md
 
 # Temp/misc
+.tmp/
 nul
+NUL
 network_requests.txt
+*.bak
+/AndroidManifest.xml
 
 # Log files
 *.log

CONTRIBUTING.md

@@ -86,7 +86,7 @@ Translation files are located in `lib/l10n/arb/`.
    git remote add upstream https://github.com/zarzet/SpotiFLAC-Mobile.git
    ```
 
-3. **Use FVM (Flutter Version: 3.38.1)**
+3. **Use FVM (Flutter Version: 3.41.5)**
    ```bash
    fvm use
    ```

README.md

@@ -1,9 +1,9 @@
 <div align="center">
 
 <picture>
-  <source media="(prefers-color-scheme: dark)" srcset="assets/images/banner-readme-dark.png">
-  <source media="(prefers-color-scheme: light)" srcset="assets/images/banner-readme-light.png">
-  <img alt="SpotiFLAC Mobile" src="assets/images/banner-readme-light.png" width="650" height="auto">
+  <source media="(prefers-color-scheme: dark)" srcset="assets/readme/banner-readme-dark.png">
+  <source media="(prefers-color-scheme: light)" srcset="assets/readme/banner-readme-light.png">
+  <img alt="SpotiFLAC Mobile" src="assets/readme/banner-readme-light.png" width="650" height="auto">
 </picture>
 
 <p align="center">
@@ -28,10 +28,10 @@
 ## Screenshots
 
 <p align="center">
-  <img src="assets/images/1.jpg?v=2" width="200" />
-  <img src="assets/images/2.jpg?v=2" width="200" />
-  <img src="assets/images/3.jpg?v=2" width="200" />
-  <img src="assets/images/4.jpg?v=2" width="200" />
+  <img src="assets/readme/1.jpg?v=2" width="200" />
+  <img src="assets/readme/2.jpg?v=2" width="200" />
+  <img src="assets/readme/3.jpg?v=2" width="200" />
+  <img src="assets/readme/4.jpg?v=2" width="200" />
 </p>
 
 ---
@@ -59,7 +59,7 @@ Extensions let the community add new music sources and features without waiting
 ## Related Projects
 
 ### [SpotiFLAC (Desktop)](https://github.com/afkarxyz/SpotiFLAC)
-Download music in true lossless FLAC from Tidal, Qobuz & Amazon Music available for Windows, macOS & Linux.
+Download music in true lossless FLAC from extension-provided sources on Windows, macOS & Linux.
 
 ### [SpotiFLAC (Python Module)](https://github.com/ShuShuzinhuu/SpotiFLAC-Module-Version)
 Python library for SpotiFLAC integration, maintained by [@ShuShuzinhuu](https://github.com/ShuShuzinhuu).
@@ -80,7 +80,7 @@ Starting from version 3.8.0, SpotiFLAC uses a decentralized extension repository
 <summary><b>Why is my download failing with "Song not found"?</b></summary>
 <br>
 
-The track may not be available on the streaming services. Try enabling more providers under **Settings > Download > Provider Priority**, or install additional extensions like Amazon Music from the Store.
+The track may not be available from your enabled providers. Try enabling more providers under **Settings > Extensions > Provider Priority**, or install additional download extensions from the Store.
 
 </details>
 
@@ -88,10 +88,7 @@ The track may not be available on the streaming services. Try enabling more prov
 <summary><b>Why are some tracks downloading in lower quality?</b></summary>
 <br>
 
-Quality depends on what's available from the streaming service and its extensions. Built-in providers:
-- **Tidal** up to 24-bit/192kHz
-- **Qobuz** up to 24-bit/192kHz
-- **Deezer** up to 16-bit/44.1kHz
+Quality depends on what's available from the source and the installed download extension. Check each extension's quality options and service notes in the app.
 
 </details>
 

analysis_options.yaml

@@ -9,6 +9,9 @@
 # packages, and plugins designed to encourage good coding practices.
 include: package:flutter_lints/flutter.yaml
 
+plugins:
+  riverpod_lint: 3.1.4-dev.3
+
 analyzer:
   exclude:
     - build/**
@@ -19,9 +22,6 @@ analyzer:
     strict-casts: true
     strict-inference: true
     strict-raw-types: true
-  plugins:
-    - custom_lint
-
 linter:
   # The lint rules applied to this project can be customized in the
   # section below to disable rules from the `package:flutter_lints/flutter.yaml`
@@ -44,9 +44,5 @@ linter:
     cancel_subscriptions: true
     close_sinks: true
 
-custom_lint:
-  rules:
-    - avoid_public_notifier_properties
-
 # Additional information about this file can be found at
 # https://dart.dev/guides/language/analysis-options

android/app/build.gradle.bak

@@ -1,71 +0,0 @@
-plugins {
-    id "com.android.application"
-    id "kotlin-android"
-    id "dev.flutter.flutter-gradle-plugin"
-}
-
-def localProperties = new Properties()
-def localPropertiesFile = rootProject.file('local.properties')
-if (localPropertiesFile.exists()) {
-    localPropertiesFile.withReader('UTF-8') { reader ->
-        localProperties.load(reader)
-    }
-}
-
-def flutterVersionCode = localProperties.getProperty('flutter.versionCode')
-if (flutterVersionCode == null) {
-    flutterVersionCode = '1'
-}
-
-def flutterVersionName = localProperties.getProperty('flutter.versionName')
-if (flutterVersionName == null) {
-    flutterVersionName = '1.0'
-}
-
-android {
-    namespace "com.zarz.spotiflac"
-    compileSdk flutter.compileSdkVersion
-    ndkVersion flutter.ndkVersion
-
-    compileOptions {
-        sourceCompatibility JavaVersion.VERSION_1_8
-        targetCompatibility JavaVersion.VERSION_1_8
-    }
-
-    kotlinOptions {
-        jvmTarget = '1.8'
-    }
-
-    sourceSets {
-        main.java.srcDirs += 'src/main/kotlin'
-    }
-
-    defaultConfig {
-        applicationId "com.zarz.spotiflac"
-        minSdkVersion flutter.minSdkVersion
-        targetSdk flutter.targetSdkVersion
-        versionCode flutterVersionCode.toInteger()
-        versionName flutterVersionName
-    }
-
-    buildTypes {
-        release {
-            signingConfig signingConfigs.debug
-            minifyEnabled false
-            shrinkResources false
-        }
-    }
-}
-
-flutter {
-    source '../..'
-}
-
-dependencies {
-    // Go backend library (gomobile generated)
-    implementation fileTree(dir: 'libs', include: ['*.aar'])
-    
-    // Kotlin coroutines for async Go backend calls
-    implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-core:1.7.3'
-    implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-android:1.7.3'
-}

android/app/build.gradle.kts

@@ -120,8 +120,8 @@ dependencies {
     // Include all AAR and JAR files from libs folder
     implementation(fileTree(mapOf("dir" to "libs", "include" to listOf("*.jar", "*.aar"))))
     
-    implementation("org.jetbrains.kotlinx:kotlinx-coroutines-android:1.10.2")
-    implementation("androidx.lifecycle:lifecycle-runtime-ktx:2.10.0")
+    implementation("org.jetbrains.kotlinx:kotlinx-coroutines-android:1.11.0")
+    implementation("androidx.lifecycle:lifecycle-runtime-ktx:2.11.0-beta02")
     implementation("androidx.documentfile:documentfile:1.1.0")
     implementation("androidx.activity:activity-ktx:1.13.0")
     implementation("com.antonkarpenko:ffmpeg-kit-full:2.1.0")

android/app/src/main/kotlin/com/example/temp_project/MainActivity.kt

@@ -1,5 +0,0 @@
-package com.example.temp_project
-
-import io.flutter.embedding.android.FlutterActivity
-
-class MainActivity : FlutterActivity()

android/app/src/main/kotlin/com/zarz/spotiflac/DownloadService.kt

@@ -690,7 +690,8 @@ class DownloadService : Service() {
                             request.itemId,
                             request.requestJson,
                             request.itemJson,
-                            result
+                            result,
+                            settingsJson
                         ) {
                             nativeWorkerCancelRequested ||
                                 nativeWorkerPaused ||

android/app/src/main/kotlin/com/zarz/spotiflac/MainActivity.kt

@@ -307,6 +307,8 @@ class MainActivity: FlutterFragmentActivity() {
             ".mp3" -> "audio/mpeg"
             ".opus" -> "audio/ogg"
             ".flac" -> "audio/flac"
+            ".wav" -> "audio/wav"
+            ".aiff", ".aif", ".aifc" -> "audio/aiff"
             ".lrc" -> "application/octet-stream"
             else -> "application/octet-stream"
         }
@@ -772,6 +774,7 @@ class MainActivity: FlutterFragmentActivity() {
         return when {
             name.endsWith(".m4a") -> ".m4a"
             name.endsWith(".mp4") -> ".mp4"
+            name.endsWith(".aac") -> ".aac"
             name.endsWith(".mp3") -> ".mp3"
             name.endsWith(".opus") -> ".opus"
             name.endsWith(".flac") -> ".flac"
@@ -783,9 +786,15 @@ class MainActivity: FlutterFragmentActivity() {
     private fun extFromMimeType(mime: String?): String {
         return when (mime) {
             "audio/mp4" -> ".m4a"
+            "audio/aac" -> ".aac"
+            "audio/eac3" -> ".m4a"
+            "audio/ac3" -> ".m4a"
+            "audio/ac4" -> ".m4a"
             "audio/mpeg" -> ".mp3"
             "audio/ogg" -> ".opus"
             "audio/flac" -> ".flac"
+            "audio/wav", "audio/x-wav", "audio/wave", "audio/vnd.wave" -> ".wav"
+            "audio/aiff", "audio/x-aiff" -> ".aiff"
             else -> ""
         }
     }
@@ -1032,6 +1041,48 @@ class MainActivity: FlutterFragmentActivity() {
         }
     }
 
+    /**
+     * Write a ".lrc" sidecar next to a SAF audio document. The sidecar reuses
+     * the audio file's base name (e.g. "Song.flac" -> "Song.lrc") and is created
+     * in the same parent directory. Used by re-enrich when the user's lyrics
+     * mode requests an external/both sidecar. Best-effort: failures are logged
+     * and swallowed so they never abort the metadata enrichment itself.
+     */
+    private fun writeSafSidecarLrc(audioUri: Uri, lrcContent: String): Boolean {
+        if (lrcContent.isBlank()) return false
+        try {
+            val parent = safParentDir(audioUri) ?: run {
+                android.util.Log.w("SpotiFLAC", "LRC sidecar: no SAF parent dir")
+                return false
+            }
+            val audioName = try {
+                DocumentFile.fromSingleUri(this, audioUri)?.name
+            } catch (_: Exception) {
+                null
+            } ?: return false
+            val baseName = audioName.substringBeforeLast('.', audioName)
+            val lrcName = "$baseName.lrc"
+
+            val target = createOrReuseDocumentFile(
+                parent,
+                "application/octet-stream",
+                lrcName
+            ) ?: run {
+                android.util.Log.w("SpotiFLAC", "LRC sidecar: failed to create $lrcName")
+                return false
+            }
+
+            contentResolver.openOutputStream(target.uri, "wt")?.use { output ->
+                output.write(lrcContent.toByteArray(Charsets.UTF_8))
+            } ?: return false
+            android.util.Log.d("SpotiFLAC", "LRC sidecar written: $lrcName")
+            return true
+        } catch (e: Exception) {
+            android.util.Log.w("SpotiFLAC", "LRC sidecar write failed: ${e.message}")
+            return false
+        }
+    }
+
     /**
      * Extract the audio filename referenced by a CUE sheet file.
      * Reads the FILE "name" TYPE line from the .cue text.
@@ -1063,7 +1114,17 @@ class MainActivity: FlutterFragmentActivity() {
     }
 
     private val cueSiblingAudioExtensions = listOf(
-        ".flac", ".wav", ".ape", ".mp3", ".ogg", ".wv", ".m4a"
+        ".flac", ".wav", ".ape", ".mp3", ".ogg", ".wv", ".m4a", ".mp4", ".aac"
+    )
+
+    // Audio file extensions that the local library scanner accepts. Must stay in
+    // sync with supportedAudioFormats in go_backend/library_scan.go so that every
+    // format the Go engine can read (FLAC, M4A/MP4/AAC, MP3, Opus/OGG, APE/WV/MPC,
+    // WAV, AIFF) is also enumerated here during the SAF folder walk. (.cue is
+    // handled separately.)
+    private val libraryScanAudioExtensions = setOf(
+        ".flac", ".m4a", ".mp4", ".aac", ".mp3", ".opus", ".ogg",
+        ".ape", ".wv", ".mpc", ".wav", ".aiff", ".aif"
     )
 
     private fun getSafChildFileLookup(
@@ -1135,7 +1196,7 @@ class MainActivity: FlutterFragmentActivity() {
             it.currentFile = "Scanning folders..."
         }
 
-        val supportedAudioExt = setOf(".flac", ".m4a", ".mp3", ".opus", ".ogg")
+        val supportedAudioExt = libraryScanAudioExtensions
         val audioFiles = mutableListOf<Pair<DocumentFile, String>>()
         val cueFiles = mutableListOf<Pair<DocumentFile, DocumentFile>>()
         val visitedDirUris = mutableSetOf<String>()
@@ -1435,7 +1496,7 @@ class MainActivity: FlutterFragmentActivity() {
             it.currentFile = "Scanning folders..."
         }
 
-        val supportedAudioExt = setOf(".flac", ".m4a", ".mp3", ".opus", ".ogg")
+        val supportedAudioExt = libraryScanAudioExtensions
         val audioFiles = mutableListOf<Triple<DocumentFile, String, Long>>()
         val cueFilesToScan = mutableListOf<Triple<DocumentFile, DocumentFile, Long>>()
         val unchangedCueFiles = mutableListOf<Pair<DocumentFile, DocumentFile>>()
@@ -2599,6 +2660,23 @@ class MainActivity: FlutterFragmentActivity() {
                             }
                             result.success(response)
                         }
+                        "writeSafSidecarLrc" -> {
+                            val safUri = call.argument<String>("saf_uri") ?: ""
+                            val lyrics = call.argument<String>("lyrics") ?: ""
+                            val response = withContext(Dispatchers.IO) {
+                                try {
+                                    val uri = Uri.parse(safUri)
+                                    if (writeSafSidecarLrc(uri, lyrics)) {
+                                        """{"success":true}"""
+                                    } else {
+                                        """{"success":false,"error":"Failed to write LRC sidecar"}"""
+                                    }
+                                } catch (e: Exception) {
+                                    """{"success":false,"error":"${e.message?.replace("\"", "'")}"}"""
+                                }
+                            }
+                            result.success(response)
+                        }
                         "downloadCoverToFile" -> {
                             val coverUrl = call.argument<String>("cover_url") ?: ""
                             val outputPath = call.argument<String>("output_path") ?: ""
@@ -2756,6 +2834,9 @@ class MainActivity: FlutterFragmentActivity() {
                                             if (!writeUriFromPath(uri, tempPath)) {
                                                 return@withContext """{"error":"Failed to write enriched metadata back to SAF file"}"""
                                             }
+                                            if (obj.optBoolean("write_external_lrc", false)) {
+                                                writeSafSidecarLrc(uri, obj.optString("lyrics", ""))
+                                            }
                                             raw
                                         } catch (e: Exception) {
                                             try { File(tempPath).delete() } catch (_: Exception) {}
@@ -3090,6 +3171,17 @@ class MainActivity: FlutterFragmentActivity() {
                             }
                             result.success(response)
                         }
+                        "findCollectionAcrossExtensions" -> {
+                            val requestJson = call.arguments as? String ?: "{}"
+                            val response: String = withContext(Dispatchers.IO) {
+                                val method = Gobackend::class.java.getMethod(
+                                    "findCollectionAcrossExtensionsJSON",
+                                    String::class.java
+                                )
+                                method.invoke(null, requestJson) as? String ?: "[]"
+                            }
+                            result.success(response)
+                        }
                         "enrichTrackWithExtension" -> {
                             val extensionId = call.argument<String>("extension_id") ?: ""
                             val trackJson = call.argument<String>("track") ?: "{}"
@@ -3475,7 +3567,7 @@ class MainActivity: FlutterFragmentActivity() {
                                                 } catch (_: Exception) { "" }
                                                 val cueBaseName = cueName.substringBeforeLast('.')
                                                 if (cueBaseName.isNotBlank()) {
-                                                    val commonExts = listOf(".flac", ".wav", ".ape", ".mp3", ".ogg", ".wv", ".m4a")
+                                                    val commonExts = listOf(".flac", ".wav", ".ape", ".mp3", ".ogg", ".wv", ".m4a", ".mp4", ".aac")
                                                     for (ext in commonExts) {
                                                         audioDoc = try { parentDir.findFile(cueBaseName + ext) } catch (_: Exception) { null }
                                                         if (audioDoc != null) break

android/app/src/main/kotlin/com/zarz/spotiflac/NativeDownloadFinalizer.kt

@@ -16,6 +16,7 @@ import com.antonkarpenko.ffmpegkit.ReturnCode
 import gobackend.Gobackend
 import org.json.JSONObject
 import java.io.File
+import java.io.RandomAccessFile
 import java.nio.ByteBuffer
 import java.util.Locale
 import java.util.concurrent.CancellationException
@@ -29,7 +30,7 @@ object NativeDownloadFinalizer {
     const val NATIVE_WORKER_CONTRACT_VERSION = 1
     // Native finalizer owns background-safe history writes while Flutter may be suspended.
     // Keep this schema contract in sync with Dart HistoryDatabase before bumping either side.
-    private const val HISTORY_SCHEMA_VERSION = 8
+    private const val HISTORY_SCHEMA_VERSION = 9
     private val activeFFmpegSessionIds = mutableSetOf<Long>()
     private val nativeFFmpegSessionIds = mutableSetOf<Long>()
     private val activeFFmpegSessionLock = Any()
@@ -72,6 +73,8 @@ object NativeDownloadFinalizer {
         "quality",
         "bit_depth",
         "sample_rate",
+        "bitrate",
+        "format",
         "genre",
         "composer",
         "label",
@@ -95,6 +98,7 @@ object NativeDownloadFinalizer {
         ".ogg",
         ".wav",
         ".aac",
+        ".mp4",
     )
 
     private data class FinalizeInput(
@@ -112,6 +116,7 @@ object NativeDownloadFinalizer {
         var bitDepth: Int?,
         var sampleRate: Int?,
         var bitrateKbps: Int? = null,
+        var audioCodec: String? = null,
         var pendingExternalLrc: String? = null,
         var pendingExternalLrcFileName: String? = null,
     )
@@ -141,6 +146,7 @@ object NativeDownloadFinalizer {
         requestJson: String,
         itemJson: String,
         result: JSONObject,
+        settingsJson: String = "{}",
         shouldCancel: () -> Boolean = { false },
     ): JSONObject {
         if (!result.optBoolean("success", false)) return result
@@ -174,6 +180,9 @@ object NativeDownloadFinalizer {
             sampleRate = optPositiveInt(result, "actual_sample_rate"),
             bitrateKbps = optPositiveBitrateKbps(result, "bitrate")
                 ?: optPositiveBitrateKbps(result, "actual_bitrate"),
+            audioCodec = normalizeAudioCodec(
+                result.optString("audio_codec", "").ifBlank { result.optString("format", "") },
+            ),
         )
 
         try {
@@ -209,14 +218,20 @@ object NativeDownloadFinalizer {
                 refreshFinalAudioQualityMetadata(context, result, state)
             }
 
-            val history = buildHistoryRow(effectiveInput, state)
-            upsertHistory(context, history)
+            val saveDownloadHistory = parseObject(settingsJson)
+                .optBoolean("save_download_history", true)
+            val history = if (saveDownloadHistory) {
+                buildHistoryRow(effectiveInput, state).also { upsertHistory(context, it) }
+            } else {
+                null
+            }
 
             result.put("file_path", state.filePath)
             if (state.fileName.isNotBlank()) result.put("file_name", state.fileName)
+            if (state.quality.isNotBlank()) result.put("quality", state.quality)
             result.put("native_finalized", true)
-            result.put("history_written", true)
-            result.put("history_item", historyToJson(history))
+            result.put("history_written", history != null)
+            if (history != null) result.put("history_item", historyToJson(history))
         } catch (e: CancellationException) {
             cleanupFailedFinalizationOutput(context, result, initialPath, state.filePath)
             result.put("success", false)
@@ -419,7 +434,13 @@ object NativeDownloadFinalizer {
                 for ((candidateOutput, mapAudioOnly) in attempts) {
                     try {
                         val audioMap = if (mapAudioOnly) "-map 0:a " else ""
-                        val command = "-v error -decryption_key ${q(candidate)} -f $inputFormat -i ${q(localInput)} ${audioMap}-c copy ${q(candidateOutput)} -y"
+                        // Force the flac muxer when the target extension is
+                        // .flac. Without this override FFmpeg keeps the ISO-BMFF
+                        // stream layout, producing FLAC-in-MP4 under a .flac
+                        // filename which downstream native FLAC tag writers
+                        // cannot read.
+                        val muxerOverride = if (candidateOutput.lowercase(Locale.ROOT).endsWith(".flac")) "-f flac " else ""
+                        val command = "-v error -decryption_key ${q(candidate)} -f $inputFormat -i ${q(localInput)} ${audioMap}-c copy ${muxerOverride}${q(candidateOutput)} -y"
                         val result = runFFmpeg(command, shouldCancel)
                         lastOutput = result.second
                         if (result.first && File(candidateOutput).exists()) {
@@ -461,13 +482,23 @@ object NativeDownloadFinalizer {
         if (!looksLikeM4a(state.filePath, state.fileName)) return
 
         val tidalHighFormat = input.request.optString("tidal_high_format", "").ifBlank { "mp3_320" }
-        val format = if (tidalHighFormat.startsWith("opus")) "opus" else "mp3"
+        val format = when {
+            tidalHighFormat.startsWith("opus") -> "opus"
+            tidalHighFormat.startsWith("aac") || tidalHighFormat.startsWith("m4a") -> "aac"
+            else -> "mp3"
+        }
+        val metadataFormat = if (format == "aac") "m4a" else format
+        val displayFormat = if (format == "aac") "AAC" else format.uppercase(Locale.ROOT)
         val bitrate = if (tidalHighFormat.contains("_")) {
             "${tidalHighFormat.substringAfterLast("_")}k"
         } else {
             if (format == "opus") "128k" else "320k"
         }
-        val ext = if (format == "opus") ".opus" else ".mp3"
+        val ext = when (format) {
+            "opus" -> ".opus"
+            "aac" -> ".m4a"
+            else -> ".mp3"
+        }
         val localInput = materializeForFFmpeg(context, input, state)
         val deleteLocalInput = state.filePath.startsWith("content://")
         val output = buildOutputPath(localInput, ext)
@@ -475,6 +506,8 @@ object NativeDownloadFinalizer {
         try {
             val command = if (format == "opus") {
                 "-v error -hide_banner -i ${q(localInput)} -codec:a libopus -b:a $bitrate -vbr on -compression_level 10 -map 0:a ${q(output)} -y"
+            } else if (format == "aac") {
+                "-v error -hide_banner -i ${q(localInput)} -codec:a aac -b:a $bitrate -map 0:a -f mp4 ${q(output)} -y"
             } else {
                 "-v error -hide_banner -i ${q(localInput)} -codec:a libmp3lame -b:a $bitrate -map 0:a -id3v2_version 3 ${q(output)} -y"
             }
@@ -482,14 +515,14 @@ object NativeDownloadFinalizer {
             if (!result.first || !File(output).exists()) {
                 throw IllegalStateException("HIGH conversion failed: ${result.second}")
             }
-            embedBasicMetadata(context, output, input, format)
+            embedBasicMetadata(context, output, input, metadataFormat)
             replaceStatePath(context, input, state, output, deleteOld = true)
             adoptedOutput = true
         } finally {
             if (!adoptedOutput) File(output).delete()
             if (deleteLocalInput) File(localInput).delete()
         }
-        state.quality = "${format.uppercase(Locale.ROOT)} ${bitrate.removeSuffix("k")}kbps"
+        state.quality = "$displayFormat ${bitrate.removeSuffix("k")}kbps"
         state.bitDepth = null
         state.sampleRate = null
     }
@@ -501,13 +534,37 @@ object NativeDownloadFinalizer {
         shouldCancel: () -> Boolean,
     ) {
         if (requestQuality(input) == "HIGH" || outputExt(input) != ".flac") return
-        if (!looksLikeM4a(state.filePath, state.fileName) && !shouldForceContainerConversion(input, state)) return
+        val requestedDecryptionExt = requestedDecryptionOutputExt(input)
+        val forceContainerConversion = shouldForceContainerConversion(input, state)
+        if (!forceContainerConversion && requestedDecryptionExt.isNotBlank() && requestedDecryptionExt != ".flac") return
+        val mayNeedContainerConversion = forceContainerConversion ||
+            looksLikeM4a(state.filePath, state.fileName) ||
+            state.filePath.startsWith("content://")
+        if (!mayNeedContainerConversion) return
 
         val localInput = materializeForFFmpeg(context, input, state)
         val deleteLocalInput = state.filePath.startsWith("content://")
         val output = buildOutputPath(localInput, ".flac")
         var adoptedOutput = false
         try {
+            val codec = probePrimaryAudioCodec(localInput, shouldCancel)
+            val isAlreadyNativeFlac = codec == "flac" && isNativeFlacFile(localInput)
+            if (!isLosslessAudioCodec(codec)) {
+                Log.d(TAG, "Preserving native container; audio codec is ${codec.ifBlank { "unknown" }}")
+                return
+            }
+            if (isAlreadyNativeFlac) {
+                Log.d(TAG, "Native FLAC payload detected; publishing as FLAC and embedding metadata")
+                val nativeFlacOutput = if (localInput.lowercase(Locale.ROOT).endsWith(".flac")) {
+                    localInput
+                } else {
+                    File(localInput).copyTo(File(output), overwrite = true).absolutePath
+                }
+                embedBasicMetadata(context, nativeFlacOutput, input, "flac")
+                replaceStatePath(context, input, state, nativeFlacOutput, deleteOld = true)
+                adoptedOutput = true
+                return
+            }
             val result = runFFmpeg(
                 "-v error -xerror -i ${q(localInput)} -c:a flac -compression_level 8 ${q(output)} -y",
                 shouldCancel,
@@ -633,6 +690,17 @@ object NativeDownloadFinalizer {
 
             val bitDepth = optPositiveInt(metadata, "bit_depth")
             val sampleRate = optPositiveInt(metadata, "sample_rate")
+            val probedCodec = normalizeAudioCodec(
+                metadata.optString("audio_codec", "").ifBlank {
+                    metadata.optString("codec", "").ifBlank {
+                        metadata.optString("format", "")
+                    }
+                }
+            )
+            if (probedCodec != null) {
+                state.audioCodec = probedCodec
+                result.put("audio_codec", probedCodec)
+            }
             if (bitDepth != null) {
                 state.bitDepth = bitDepth
                 result.put("actual_bit_depth", bitDepth)
@@ -643,7 +711,7 @@ object NativeDownloadFinalizer {
             }
             val bitrateKbps = optPositiveBitrateKbps(metadata, "bitrate")
                 ?: optPositiveBitrateKbps(metadata, "bit_rate")
-            if (bitrateKbps != null) {
+            if (bitrateKbps != null && isLossyAudioCodec(state.audioCodec)) {
                 state.bitrateKbps = bitrateKbps
                 result.put("bitrate", bitrateKbps)
             }
@@ -654,6 +722,7 @@ object NativeDownloadFinalizer {
                 bitDepth = state.bitDepth,
                 sampleRate = state.sampleRate,
                 bitrateKbps = state.bitrateKbps,
+                audioCodec = state.audioCodec,
                 storedQuality = state.quality,
             )
             if (displayQuality != null) {
@@ -691,15 +760,19 @@ object NativeDownloadFinalizer {
         bitDepth: Int?,
         sampleRate: Int?,
         bitrateKbps: Int?,
+        audioCodec: String? = null,
         storedQuality: String?,
     ): String? {
-        val format = audioFormatForPath(filePath, fileName)
+        val format = audioFormatForCodec(audioCodec) ?: audioFormatForPath(filePath, fileName)
         if (format == "OPUS" ||
             format == "MP3" ||
             format == "AAC" ||
+            format == "EAC3" ||
+            format == "AC3" ||
+            format == "AC4" ||
             (format == "M4A" && (bitDepth == null || bitDepth <= 0))
         ) {
-            return if (bitrateKbps != null && bitrateKbps > 0) {
+            return if (bitrateKbps != null && bitrateKbps >= 16) {
                 "$format ${bitrateKbps}kbps"
             } else {
                 nonPlaceholderQuality(storedQuality) ?: format
@@ -715,6 +788,43 @@ object NativeDownloadFinalizer {
         return nonPlaceholderQuality(storedQuality) ?: normalizeOptional(storedQuality)
     }
 
+    private fun audioFormatForCodec(codec: String?): String? {
+        return when (normalizeAudioCodec(codec)) {
+            "flac" -> "FLAC"
+            "alac" -> "ALAC"
+            "aac" -> "AAC"
+            "eac3" -> "EAC3"
+            "ac3" -> "AC3"
+            "ac4" -> "AC4"
+            "mp3" -> "MP3"
+            "opus" -> "OPUS"
+            else -> null
+        }
+    }
+
+    private fun isLossyAudioCodec(codec: String?): Boolean {
+        return when (normalizeAudioCodec(codec)) {
+            "aac", "eac3", "ac3", "ac4", "mp3", "opus", "m4a" -> true
+            else -> false
+        }
+    }
+
+    private fun normalizeAudioCodec(codec: String?): String? {
+        val normalized = normalizeOptional(codec)
+            ?.lowercase(Locale.ROOT)
+            ?.replace('-', '_')
+            ?: return null
+        return when (normalized) {
+            "mp4a" -> "aac"
+            "ec_3" -> "eac3"
+            "ac_3" -> "ac3"
+            "ac_4" -> "ac4"
+            "mp4" -> "m4a"
+            "ogg" -> "opus"
+            else -> normalized
+        }
+    }
+
     private fun audioFormatForPath(filePath: String, fileName: String): String? {
         for (candidate in listOf(filePath, fileName)) {
             val lower = candidate.trim().lowercase(Locale.ROOT)
@@ -730,6 +840,11 @@ object NativeDownloadFinalizer {
 
     private fun nonPlaceholderQuality(quality: String?): String? {
         val normalized = normalizeOptional(quality) ?: return null
+        val bitrateMatch = Regex("\\b(\\d+)\\s*kbps\\b", RegexOption.IGNORE_CASE).find(normalized)
+        if (bitrateMatch != null) {
+            val bitrate = bitrateMatch.groupValues.getOrNull(1)?.toIntOrNull()
+            if (bitrate != null && bitrate < 16) return null
+        }
         val key = normalized.lowercase(Locale.ROOT).replace(Regex("[^a-z0-9]+"), "_").trim('_')
         val placeholders = setOf(
             "best",
@@ -972,10 +1087,11 @@ object NativeDownloadFinalizer {
         val genre = resultString(input, "genre").ifBlank { requestString(input, "genre") }
         val label = resultString(input, "label").ifBlank { requestString(input, "label") }
         val copyright = resultString(input, "copyright").ifBlank { requestString(input, "copyright") }
-        val lyrics = resolveLyricsLrc(input)
-        val shouldEmbedLyrics = input.request.optBoolean("embed_lyrics", false) &&
-            (input.request.optString("lyrics_mode", "embed") == "embed" ||
-                input.request.optString("lyrics_mode", "embed") == "both") &&
+        val lyricsMode = input.request.optString("lyrics_mode", "embed")
+        val shouldResolveLyrics = input.request.optBoolean("embed_lyrics", false) &&
+            (lyricsMode == "embed" || lyricsMode == "both")
+        val lyrics = if (shouldResolveLyrics) resolveLyricsLrc(input) else ""
+        val shouldEmbedLyrics = shouldResolveLyrics &&
             lyrics.isNotBlank() &&
             lyrics != "[instrumental:true]"
         if (format == "flac") {
@@ -1146,7 +1262,7 @@ object NativeDownloadFinalizer {
         return when (normalizeExt(File(path).extension)) {
             ".mp3" -> "mp3"
             ".opus", ".ogg" -> "opus"
-            ".m4a", ".mp4" -> "m4a"
+            ".m4a", ".mp4", ".aac" -> "m4a"
             else -> "flac"
         }
     }
@@ -1294,7 +1410,7 @@ object NativeDownloadFinalizer {
         val rawName = input.request.optString("saf_file_name", "")
             .ifBlank { state.fileName }
             .ifBlank { "${trackString(input, "artistName", input.request.optString("artist_name", "Artist"))} - ${trackString(input, "name", input.request.optString("track_name", "Track"))}" }
-        val knownExts = listOf(".flac", ".m4a", ".mp4", ".mp3", ".opus", ".ogg", ".lrc")
+        val knownExts = listOf(".flac", ".m4a", ".mp4", ".aac", ".mp3", ".opus", ".ogg", ".lrc")
         var base = rawName.trim()
         val lower = base.lowercase(Locale.ROOT)
         for (knownExt in knownExts) {
@@ -1315,19 +1431,66 @@ object NativeDownloadFinalizer {
     private fun shouldForceContainerConversion(input: FinalizeInput, state: FinalizeState): Boolean {
         if (input.result.optBoolean("requires_container_conversion", false)) return true
         if (input.request.optBoolean("requires_container_conversion", false)) return true
+        return false
+    }
 
-        val actualExt = normalizeExt(
-            input.result.optString("actual_extension", "")
-                .ifBlank { input.result.optString("output_extension", "") }
+    private fun probePrimaryAudioCodec(path: String, shouldCancel: () -> Boolean = { false }): String {
+        val result = runFFmpeg("-hide_banner -nostdin -i ${q(path)} -map 0:a:0 -frames:a 1 -f null -", shouldCancel)
+        val output = result.second
+        val match = Regex("Audio:\\s*([^,\\s]+)", RegexOption.IGNORE_CASE).find(output)
+        return match?.groupValues?.getOrNull(1)
+            ?.trim()
+            ?.lowercase(Locale.ROOT)
+            ?.replace('-', '_')
+            .orEmpty()
+    }
+
+    /**
+     * Returns true when the file on [path] starts with the native FLAC magic
+     * bytes (`fLaC`). A file may contain a FLAC audio stream yet live inside
+     * an MP4/fMP4 container (e.g. some Amazon Music downloads); native FLAC
+     * tag writers require the raw fLaC header, so we must detect that mismatch
+     * before skipping the container conversion step.
+     */
+    private fun isNativeFlacFile(path: String): Boolean {
+        return try {
+            RandomAccessFile(path, "r").use { raf ->
+                if (raf.length() < 4L) return false
+                val header = ByteArray(4)
+                raf.readFully(header)
+                header[0] == 0x66.toByte() && // 'f'
+                    header[1] == 0x4C.toByte() && // 'L'
+                    header[2] == 0x61.toByte() && // 'a'
+                    header[3] == 0x43.toByte() // 'C'
+            }
+        } catch (e: Exception) {
+            Log.w(TAG, "Native FLAC magic probe failed for $path: ${e.message}")
+            false
+        }
+    }
+
+    private fun isLosslessAudioCodec(codec: String): Boolean {
+        val normalized = codec.trim().lowercase(Locale.ROOT).replace('-', '_')
+        if (normalized.isBlank()) return false
+        if (normalized.startsWith("pcm_")) return true
+        return normalized in setOf(
+            "alac",
+            "flac",
+            "wavpack",
+            "ape",
+            "tta",
+            "mlp",
+            "truehd",
+            "shorten"
         )
-        if (actualExt == ".m4a" || actualExt == ".mp4") return true
+    }
 
-        val container = input.result.optString("actual_container", "")
-            .ifBlank { input.result.optString("container", "") }
-            .trim()
-            .lowercase(Locale.ROOT)
-            .removePrefix(".")
-        return container == "m4a" || container == "mp4" || container == "mov" || container == "aac"
+    private fun requestedDecryptionOutputExt(input: FinalizeInput): String {
+        val descriptor = input.result.optJSONObject("decryption")
+        return normalizeExt(
+            descriptor?.optString("output_extension", "")
+                ?.ifBlank { input.result.optString("output_extension", "") }
+        )
     }
 
     private fun validateRequestContract(request: JSONObject) {
@@ -1541,6 +1704,10 @@ object NativeDownloadFinalizer {
         values.put("quality", state.quality)
         state.bitDepth?.let { values.put("bit_depth", it) }
         state.sampleRate?.let { values.put("sample_rate", it) }
+        state.bitrateKbps?.takeIf { it >= 16 && isLossyAudioCodec(state.audioCodec) }?.let {
+            values.put("bitrate", it)
+        }
+        normalizeAudioCodec(state.audioCodec)?.let { values.put("format", it) }
         values.put("genre", normalizeOptional(result.optString("genre", "").ifBlank { input.request.optString("genre", "") }))
         values.put("composer", normalizeOptional(resultString(input, "composer").ifBlank { trackString(input, "composer", requestString(input, "composer")) }))
         values.put("label", normalizeOptional(result.optString("label", "").ifBlank { input.request.optString("label", "") }))
@@ -1597,6 +1764,8 @@ object NativeDownloadFinalizer {
                       quality TEXT,
                       bit_depth INTEGER,
                       sample_rate INTEGER,
+                      bitrate INTEGER,
+                      format TEXT,
                       genre TEXT,
                       composer TEXT,
                       label TEXT,
@@ -1612,6 +1781,8 @@ object NativeDownloadFinalizer {
 	                ensureHistoryColumn(db, "composer", "ALTER TABLE history ADD COLUMN composer TEXT")
 	                ensureHistoryColumn(db, "total_tracks", "ALTER TABLE history ADD COLUMN total_tracks INTEGER")
 	                ensureHistoryColumn(db, "total_discs", "ALTER TABLE history ADD COLUMN total_discs INTEGER")
+	                ensureHistoryColumn(db, "bitrate", "ALTER TABLE history ADD COLUMN bitrate INTEGER")
+	                ensureHistoryColumn(db, "format", "ALTER TABLE history ADD COLUMN format TEXT")
 	                ensureHistoryColumn(db, "spotify_id_norm", "ALTER TABLE history ADD COLUMN spotify_id_norm TEXT")
 	                ensureHistoryColumn(db, "isrc_norm", "ALTER TABLE history ADD COLUMN isrc_norm TEXT")
 	                ensureHistoryColumn(db, "match_key", "ALTER TABLE history ADD COLUMN match_key TEXT")
@@ -1983,6 +2154,8 @@ object NativeDownloadFinalizer {
         putCamel("quality", "quality")
         putCamel("bit_depth", "bitDepth")
         putCamel("sample_rate", "sampleRate")
+        putCamel("bitrate", "bitrate")
+        putCamel("format", "format")
         putCamel("genre", "genre")
         putCamel("composer", "composer")
         putCamel("label", "label")
@@ -2014,11 +2187,12 @@ object NativeDownloadFinalizer {
 
     private fun optPositiveBitrateKbps(obj: JSONObject, key: String): Int? {
         val value = optPositiveInt(obj, key) ?: return null
-        return if (value >= 10000) {
+        val kbps = if (value >= 10000) {
             Math.round(value / 1000.0).toInt()
         } else {
             value
         }
+        return if (kbps >= 16) kbps else null
     }
 
     private fun positiveOrNull(primary: Int, fallback: Int): Int? {

android/app/src/main/kotlin/com/zarz/spotiflac/SafDownloadHandler.kt

@@ -15,6 +15,7 @@ import java.util.Locale
 object SafDownloadHandler {
     private val safDirLock = Any()
     private const val MAX_SAF_DISPLAY_NAME_UTF8_BYTES = 180
+    private const val STAGED_SAF_MIME_TYPE = "application/octet-stream"
 
     fun handle(context: Context, requestJson: String, downloader: (String) -> String): String {
         val req = JSONObject(requestJson)
@@ -31,15 +32,15 @@ object SafDownloadHandler {
         val fileName = buildSafFileName(req, outputExt)
         val deferSafPublish = req.optBoolean("defer_saf_publish", false)
         val useStagedOutput = req.optBoolean("stage_saf_output", false) && !deferSafPublish
-        val stagedFileName = if (useStagedOutput) buildStagedSafFileName(fileName, outputExt) else fileName
-        val staleStagedFileName = buildStagedSafFileName(fileName, outputExt)
+        val stagedFileName = if (useStagedOutput) buildStagedSafFileName(fileName) else fileName
+        val stagedMimeType = if (useStagedOutput) STAGED_SAF_MIME_TYPE else mimeType
 
         val existingDir = findDocumentDir(context, treeUri, relativeDir)
         if (existingDir != null) {
             val existing = existingDir.findFile(fileName)
             if (existing != null && existing.isFile && existing.length() > 0) {
                 if (useStagedOutput || deferSafPublish) {
-                    existingDir.findFile(staleStagedFileName)?.delete()
+                    deleteStaleStagedFiles(existingDir, fileName, outputExt)
                 }
                 val obj = JSONObject()
                 obj.put("success", true)
@@ -55,7 +56,7 @@ object SafDownloadHandler {
             ?: return errorJson("Failed to access SAF directory")
 
         if (deferSafPublish) {
-            targetDir.findFile(staleStagedFileName)?.delete()
+            deleteStaleStagedFiles(targetDir, fileName, outputExt)
             val workingExt = outputExt.ifBlank { ".tmp" }
             val workingFile = File.createTempFile("native_saf_work_", workingExt, context.cacheDir)
             Log.i("SpotiFLAC", "SAF deferred native output: target=$fileName working=${workingFile.name}")
@@ -89,7 +90,7 @@ object SafDownloadHandler {
             }
         }
 
-        var document = createOrReuseDocumentFile(targetDir, mimeType, stagedFileName)
+        var document = createOrReuseDocumentFile(targetDir, stagedMimeType, stagedFileName)
             ?: return errorJson("Failed to create SAF file")
 
         val pfd = context.contentResolver.openFileDescriptor(document.uri, "rw")
@@ -121,14 +122,14 @@ object SafDownloadHandler {
                         if (actualExt.isNotBlank() && actualExt != outputExt) {
                             val actualFileName = buildSafFileName(req, actualExt)
                             val actualStagedFileName = if (useStagedOutput) {
-                                buildStagedSafFileName(actualFileName, actualExt)
+                                buildStagedSafFileName(actualFileName)
                             } else {
                                 actualFileName
                             }
                             val actualMimeType = mimeTypeForExt(actualExt)
                             val replacement = createOrReuseDocumentFile(
                                 targetDir,
-                                actualMimeType,
+                                if (useStagedOutput) STAGED_SAF_MIME_TYPE else actualMimeType,
                                 actualStagedFileName
                             ) ?: throw IllegalStateException(
                                 "failed to create SAF output with actual extension"
@@ -212,8 +213,9 @@ object SafDownloadHandler {
             val targetDir = ensureDocumentDir(context, treeUri, relativeDir) ?: return null
             val finalName = sanitizeFilename(fileName)
             val ext = normalizeExt(finalName.substringAfterLast('.', ""))
-            val stagedName = buildStagedSafFileName(finalName, ext)
-            val document = createOrReuseDocumentFile(targetDir, mimeType, stagedName)
+            val stagedName = buildStagedSafFileName(finalName)
+            deleteStaleStagedFiles(targetDir, finalName, ext)
+            val document = createOrReuseDocumentFile(targetDir, STAGED_SAF_MIME_TYPE, stagedName)
                 ?: return null
             stagedDocument = document
             val outputStream = context.contentResolver.openOutputStream(document.uri, "wt")
@@ -288,13 +290,17 @@ object SafDownloadHandler {
         return safeName + normalizedExt
     }
 
-    private fun buildStagedSafFileName(fileName: String, outputExt: String): String {
+    private fun buildStagedSafFileName(fileName: String): String {
+        val safeName = sanitizeFilename(fileName)
+        return "$safeName.partial"
+    }
+
+    private fun buildLegacyStagedSafFileName(fileName: String, outputExt: String): String {
         val safeName = sanitizeFilename(fileName)
         val ext = normalizeExt(outputExt)
         if (ext.isNotBlank() && safeName.lowercase(Locale.ROOT).endsWith(ext)) {
             return safeName.dropLast(ext.length).trimEnd('.', ' ') + ".partial$ext"
         }
-
         val dot = safeName.lastIndexOf('.')
         if (dot > 0 && dot < safeName.lastIndex) {
             return safeName.substring(0, dot).trimEnd('.', ' ') +
@@ -304,6 +310,19 @@ object SafDownloadHandler {
         return "$safeName.partial"
     }
 
+    private fun deleteStaleStagedFiles(parent: DocumentFile, fileName: String, outputExt: String) {
+        val stagedNames = linkedSetOf(
+            buildStagedSafFileName(fileName),
+            buildLegacyStagedSafFileName(fileName, outputExt)
+        )
+        for (stagedName in stagedNames) {
+            try {
+                parent.findFile(stagedName)?.delete()
+            } catch (_: Exception) {
+            }
+        }
+    }
+
     private fun sanitizeFilename(name: String): String {
         var sanitized = name
             .replace("/", " ")

android/gradle.properties

@@ -1,2 +1,6 @@
 org.gradle.jvmargs=-Xmx2g -XX:MaxMetaspaceSize=512m -XX:ReservedCodeCacheSize=256m -XX:+HeapDumpOnOutOfMemoryError
 android.useAndroidX=true
+# This builtInKotlin flag was added automatically by Flutter migrator
+android.builtInKotlin=false
+# This newDsl flag was added automatically by Flutter migrator
+android.newDsl=false

android/settings.gradle.kts

@@ -19,7 +19,7 @@ pluginManagement {
 
 plugins {
     id("dev.flutter.flutter-plugin-loader") version "1.0.0"
-    id("com.android.application") version "8.13.2" apply false
+    id("com.android.application") version "9.2.1" apply false
     id("org.jetbrains.kotlin.android") version "2.3.21" apply false
 }
 

apps.json

@@ -7,12 +7,12 @@
       "name": "SpotiFLAC Mobile",
       "bundleIdentifier": "com.zarzet.spotiflac",
       "developerName": "zarzet",
-      "version": "4.5.0",
-      "versionDate": "2026-05-06",
-      "downloadURL": "https://github.com/zarzet/SpotiFLAC-Mobile/releases/download/v4.5.0/SpotiFLAC-v4.5.0-ios-unsigned.ipa",
+      "version": "4.5.6",
+      "versionDate": "2026-06-01",
+      "downloadURL": "https://github.com/zarzet/SpotiFLAC-Mobile/releases/download/v4.5.6/SpotiFLAC-v4.5.6-ios-unsigned.ipa",
       "localizedDescription": "SpotiFLAC Mobile is written in Flutter. Download tracks in true FLAC from Tidal, Qobuz, & Amazon Music.",
       "iconURL": "https://raw.githubusercontent.com/zarzet/SpotiFLAC-Mobile/main/assets/images/logo.png",
-      "size": 37191956
+      "size": 34059797
     }
   ]
 }

crowdin.yml

@@ -3,9 +3,11 @@ files:
     translation: /lib/l10n/arb/app_%locale%.arb
     languages_mapping:
       locale:
-        # Short codes for single-variant languages
+        # Keys MUST be the project's Crowdin language ids; values are the
+        # %locale% suffix used in app_%locale%.arb (underscores so Flutter
+        # gen-l10n parses them — hyphenated filenames break gen-l10n).
+        ar: ar
         de: de
-        es: es
         es-ES: es_ES
         fr: fr
         hi: hi
@@ -13,12 +15,9 @@ files:
         ja: ja
         ko: ko
         nl: nl
-        pt: pt
         pt-PT: pt_PT
         ru: ru
         tr: tr
         uk: uk
-        zh: zh
-        # Full codes for Chinese variants
         zh-CN: zh_CN
         zh-TW: zh_TW

go_backend/audio_metadata.go

@@ -1624,6 +1624,9 @@ func extractAnyCoverArtWithHint(filePath, displayNameHint string) ([]byte, strin
 		}
 		return data, mimeType, nil
 
+	case ".wav", ".aiff", ".aif", ".aifc":
+		return extractWAVAIFFCover(filePath)
+
 	default:
 		return nil, "", fmt.Errorf("unsupported format: %s", ext)
 	}

go_backend/audio_metadata_supplement_test.go

@@ -308,16 +308,20 @@ func TestM4AMetadataAtomHelpers(t *testing.T) {
 		t.Fatalf("ReplayGain fields = %#v", fields)
 	}
 
-	qualityPath := filepath.Join(dir, "quality.m4a")
+	qualityPath := filepath.Join(dir, "quality-alac.m4a")
 	mvhd := make([]byte, 20)
 	binary.BigEndian.PutUint32(mvhd[12:16], 1000)
 	binary.BigEndian.PutUint32(mvhd[16:20], 180000)
 	sampleEntry := make([]byte, 32)
-	copy(sampleEntry[0:4], "mp4a")
+	copy(sampleEntry[0:4], "alac")
 	binary.BigEndian.PutUint16(sampleEntry[22:24], 24)
 	sampleEntry[28] = 0xAC
 	sampleEntry[29] = 0x44
-	qualityFile := append(buildM4AAtom("ftyp", []byte("M4A \x00\x00\x00\x00")), buildM4AAtom("moov", append(buildM4AAtom("mvhd", mvhd), sampleEntry...))...)
+	alacConfig := make([]byte, 24)
+	alacConfig[5] = 24
+	binary.BigEndian.PutUint32(alacConfig[20:24], 44100)
+	alacEntryPayload := append(append([]byte{}, sampleEntry[4:]...), buildM4AAtom("alac", alacConfig)...)
+	qualityFile := append(buildM4AAtom("ftyp", []byte("M4A \x00\x00\x00\x00")), buildM4AAtom("moov", append(buildM4AAtom("mvhd", mvhd), buildM4AAtom("alac", alacEntryPayload)...))...)
 	if err := os.WriteFile(qualityPath, qualityFile, 0600); err != nil {
 		t.Fatal(err)
 	}
@@ -327,6 +331,37 @@ func TestM4AMetadataAtomHelpers(t *testing.T) {
 	if quality, err := GetAudioQuality(qualityPath); err != nil || quality.SampleRate != 44100 {
 		t.Fatalf("GetAudioQuality M4A = %#v/%v", quality, err)
 	}
+	aacQualityPath := filepath.Join(dir, "quality-aac.m4a")
+	copy(sampleEntry[0:4], "mp4a")
+	aacQualityFile := append(buildM4AAtom("ftyp", []byte("M4A \x00\x00\x00\x00")), buildM4AAtom("moov", append(buildM4AAtom("mvhd", mvhd), sampleEntry...))...)
+	if err := os.WriteFile(aacQualityPath, aacQualityFile, 0600); err != nil {
+		t.Fatal(err)
+	}
+	if quality, err := GetM4AQuality(aacQualityPath); err != nil || quality.BitDepth != 0 || quality.SampleRate != 44100 || quality.Duration != 180 {
+		t.Fatalf("GetM4AQuality AAC = %#v/%v", quality, err)
+	}
+	eac3QualityPath := filepath.Join(dir, "quality-eac3.m4a")
+	zeroMvhd := make([]byte, 20)
+	eac3SampleEntry := make([]byte, 32)
+	copy(eac3SampleEntry[0:4], "ec-3")
+	eac3SampleEntry[28] = 0xBB
+	eac3SampleEntry[29] = 0x80
+	mdhd := make([]byte, 20)
+	binary.BigEndian.PutUint32(mdhd[12:16], 48000)
+	binary.BigEndian.PutUint32(mdhd[16:20], 48000*123)
+	eac3QualityFile := append(
+		buildM4AAtom("ftyp", []byte("M4A \x00\x00\x00\x00")),
+		buildM4AAtom("moov", append(
+			append(buildM4AAtom("mvhd", zeroMvhd), buildM4AAtom("trak", buildM4AAtom("mdia", buildM4AAtom("mdhd", mdhd)))...),
+			eac3SampleEntry...,
+		))...,
+	)
+	if err := os.WriteFile(eac3QualityPath, eac3QualityFile, 0600); err != nil {
+		t.Fatal(err)
+	}
+	if quality, err := GetM4AQuality(eac3QualityPath); err != nil || quality.Codec != "eac3" || quality.Duration != 123 {
+		t.Fatalf("GetM4AQuality EAC3 mdhd fallback = %#v/%v", quality, err)
+	}
 	if _, _, ok := parseALACSpecificConfig(make([]byte, 4)); ok {
 		t.Fatal("short ALAC config should not parse")
 	}

go_backend/cross_extension_share.go

@@ -0,0 +1,442 @@
+package gobackend
+
+import (
+	"encoding/json"
+	"sort"
+	"strings"
+	"sync"
+)
+
+type CrossExtensionShareResult struct {
+	ExtensionID string `json:"extension_id"`
+	DisplayName string `json:"display_name"`
+	Found       bool   `json:"found"`
+	URL         string `json:"url,omitempty"`
+	ItemName    string `json:"item_name,omitempty"`
+	ItemArtists string `json:"item_artists,omitempty"`
+	Error       string `json:"error,omitempty"`
+}
+
+var crossExtensionShareResultCache = struct {
+	sync.RWMutex
+	entries map[string]string
+	order   []string
+}{
+	entries: make(map[string]string),
+}
+
+const crossExtensionShareResultCacheLimit = 128
+
+func FindCollectionAcrossExtensionsJSON(requestJSON string) (string, error) {
+	var req struct {
+		Name              string `json:"name"`
+		Artists           string `json:"artists"`
+		Type              string `json:"type"`
+		SourceExtensionID string `json:"source_extension_id"`
+	}
+	if err := json.Unmarshal([]byte(requestJSON), &req); err != nil {
+		return "", err
+	}
+
+	req.Name = strings.TrimSpace(req.Name)
+	req.Artists = strings.TrimSpace(req.Artists)
+	req.Type = strings.ToLower(strings.TrimSpace(req.Type))
+	req.SourceExtensionID = strings.TrimSpace(req.SourceExtensionID)
+	if req.Name == "" {
+		return "[]", nil
+	}
+	if req.Type == "" {
+		req.Type = "album"
+	}
+
+	providers := getExtensionManager().GetMetadataProviders()
+	work := make([]*extensionProviderWrapper, 0, len(providers))
+	for _, provider := range providers {
+		if provider == nil || provider.extension == nil {
+			continue
+		}
+		if provider.extension.ID == req.SourceExtensionID {
+			continue
+		}
+		work = append(work, provider)
+	}
+	cacheKey := crossExtensionShareCacheKey(req.Name, req.Artists, req.Type, req.SourceExtensionID, work)
+	if cached := getCrossExtensionShareCache(cacheKey); cached != "" {
+		return cached, nil
+	}
+
+	query := req.Name
+	if req.Artists != "" {
+		query += " " + req.Artists
+	}
+
+	results := make([]CrossExtensionShareResult, len(work))
+	var wg sync.WaitGroup
+	for i, provider := range work {
+		wg.Add(1)
+		go func(index int, p *extensionProviderWrapper) {
+			defer wg.Done()
+			results[index] = findCollectionForExtension(
+				p,
+				req.Type,
+				req.Name,
+				req.Artists,
+				query,
+			)
+		}(i, provider)
+	}
+	wg.Wait()
+
+	data, err := json.Marshal(results)
+	if err != nil {
+		return "[]", err
+	}
+	response := string(data)
+	if crossExtensionShareResultsCacheable(results) {
+		setCrossExtensionShareCache(cacheKey, response)
+	}
+	return response, nil
+}
+
+func crossExtensionShareCacheKey(name string, artists string, itemType string, sourceExtensionID string, providers []*extensionProviderWrapper) string {
+	providerKeys := make([]string, 0, len(providers))
+	for _, provider := range providers {
+		if provider == nil || provider.extension == nil {
+			continue
+		}
+		ext := provider.extension
+		displayName := ""
+		if ext.Manifest != nil {
+			displayName = ext.Manifest.DisplayName
+		}
+		providerKeys = append(providerKeys, strings.Join([]string{
+			strings.TrimSpace(ext.ID),
+			strings.TrimSpace(displayName),
+			strings.TrimSpace(ext.SourceDir),
+		}, "\x1f"))
+	}
+	sort.Strings(providerKeys)
+
+	return strings.Join([]string{
+		normalizeLooseTitle(itemType),
+		normalizeLooseTitle(name),
+		normalizeLooseArtistName(artists),
+		strings.TrimSpace(sourceExtensionID),
+		strings.Join(providerKeys, "\x1e"),
+	}, "\x1d")
+}
+
+func getCrossExtensionShareCache(key string) string {
+	if key == "" {
+		return ""
+	}
+	crossExtensionShareResultCache.RLock()
+	defer crossExtensionShareResultCache.RUnlock()
+	return crossExtensionShareResultCache.entries[key]
+}
+
+func setCrossExtensionShareCache(key string, value string) {
+	if key == "" || value == "" {
+		return
+	}
+	crossExtensionShareResultCache.Lock()
+	defer crossExtensionShareResultCache.Unlock()
+
+	if _, exists := crossExtensionShareResultCache.entries[key]; !exists {
+		crossExtensionShareResultCache.order = append(crossExtensionShareResultCache.order, key)
+	}
+	crossExtensionShareResultCache.entries[key] = value
+
+	for len(crossExtensionShareResultCache.order) > crossExtensionShareResultCacheLimit {
+		oldest := crossExtensionShareResultCache.order[0]
+		crossExtensionShareResultCache.order = crossExtensionShareResultCache.order[1:]
+		delete(crossExtensionShareResultCache.entries, oldest)
+	}
+}
+
+func crossExtensionShareResultsCacheable(results []CrossExtensionShareResult) bool {
+	for _, result := range results {
+		if result.Found {
+			continue
+		}
+		errText := strings.ToLower(strings.TrimSpace(result.Error))
+		if errText == "" ||
+			errText == "no results" ||
+			errText == "unsupported collection type" ||
+			strings.HasSuffix(errText, " not found") ||
+			strings.Contains(errText, "found without shareable link") {
+			continue
+		}
+		return false
+	}
+	return true
+}
+
+func findCollectionForExtension(
+	provider *extensionProviderWrapper,
+	itemType string,
+	name string,
+	artists string,
+	query string,
+) CrossExtensionShareResult {
+	result := CrossExtensionShareResult{
+		ExtensionID: provider.extension.ID,
+	}
+	if provider.extension.Manifest != nil {
+		result.DisplayName = provider.extension.Manifest.DisplayName
+	}
+	if result.DisplayName == "" {
+		result.DisplayName = provider.extension.ID
+	}
+
+	searchResult, err := searchCollectionCandidates(provider, itemType, query)
+	if err != nil {
+		result.Error = err.Error()
+		return result
+	}
+	if searchResult == nil || len(searchResult.Tracks) == 0 {
+		result.Error = "no results"
+		return result
+	}
+
+	var best *ExtTrackMetadata
+	switch itemType {
+	case "artist":
+		best = bestArtistTrack(searchResult.Tracks, name)
+	case "album":
+		best = bestAlbumTrack(searchResult.Tracks, name, artists)
+	default:
+		result.Error = "unsupported collection type"
+		return result
+	}
+	if best == nil {
+		result.Error = itemType + " not found"
+		return result
+	}
+
+	url := resolveCollectionShareURL(provider.extension, itemType, best)
+	if url == "" {
+		result.Error = itemType + " found without shareable link"
+		return result
+	}
+
+	result.Found = true
+	result.URL = url
+	if itemType == "artist" {
+		result.ItemName = collectionArtistName(*best)
+	} else {
+		result.ItemName = collectionAlbumName(*best)
+		result.ItemArtists = best.Artists
+	}
+	return result
+}
+
+func searchCollectionCandidates(provider *extensionProviderWrapper, itemType string, query string) (*ExtSearchResult, error) {
+	filter := ""
+	switch itemType {
+	case "album":
+		filter = "albums"
+	case "artist":
+		filter = "artists"
+	}
+
+	if filter != "" {
+		tracks, err := provider.CustomSearch(query, map[string]interface{}{
+			"filter": filter,
+			"limit":  10,
+		})
+		if err == nil && len(tracks) > 0 {
+			return &ExtSearchResult{Tracks: tracks, Total: len(tracks)}, nil
+		}
+	}
+
+	return provider.SearchTracks(query, 10)
+}
+
+func bestAlbumTrack(tracks []ExtTrackMetadata, albumName string, artists string) *ExtTrackMetadata {
+	targetAlbum := normalizeLooseTitle(albumName)
+	targetArtists := normalizeLooseArtistName(artists)
+	bestScore := 0
+	bestIndex := -1
+
+	for i := range tracks {
+		track := tracks[i]
+		album := normalizeLooseTitle(collectionAlbumName(track))
+		trackArtists := normalizeLooseArtistName(track.Artists + " " + track.AlbumArtist)
+
+		score := 0
+		if isCollectionItemType(track, "album") {
+			score += 25
+		}
+		if album == targetAlbum {
+			score += 100
+		} else if album != "" && targetAlbum != "" && (strings.Contains(album, targetAlbum) || strings.Contains(targetAlbum, album)) {
+			score += 50
+		}
+		if targetArtists != "" && (strings.Contains(trackArtists, targetArtists) || strings.Contains(targetArtists, trackArtists)) {
+			score += 30
+		}
+		if score > bestScore {
+			bestScore = score
+			bestIndex = i
+		}
+	}
+
+	if bestIndex < 0 || bestScore < 50 {
+		return nil
+	}
+	return &tracks[bestIndex]
+}
+
+func bestArtistTrack(tracks []ExtTrackMetadata, artistName string) *ExtTrackMetadata {
+	targetArtist := normalizeLooseArtistName(artistName)
+	bestScore := 0
+	bestIndex := -1
+
+	for i := range tracks {
+		artist := normalizeLooseArtistName(collectionArtistName(tracks[i]))
+		score := 0
+		if isCollectionItemType(tracks[i], "artist") {
+			score += 25
+		}
+		if artist == targetArtist {
+			score += 100
+		} else if artist != "" && targetArtist != "" && (strings.Contains(artist, targetArtist) || strings.Contains(targetArtist, artist)) {
+			score += 60
+		}
+		if score > bestScore {
+			bestScore = score
+			bestIndex = i
+		}
+	}
+
+	if bestIndex < 0 || bestScore < 60 {
+		return nil
+	}
+	return &tracks[bestIndex]
+}
+
+func resolveCollectionShareURL(ext *loadedExtension, itemType string, track *ExtTrackMetadata) string {
+	if track == nil {
+		return ""
+	}
+
+	if itemType == "album" {
+		if isCollectionItemType(*track, "album") {
+			if url := normalizeShareURL(track.ExternalURL); url != "" {
+				return url
+			}
+		}
+		if url := normalizeShareURL(track.AlbumURL); url != "" {
+			return url
+		}
+		if url := urlFromExternalLinks(track.ExternalLinks, "album"); url != "" {
+			return url
+		}
+		if url := templateShareURL(ext, "album", firstNonEmptyString(track.AlbumID, collectionID(*track, "album"), track.AlbumURL)); url != "" {
+			return url
+		}
+		return ""
+	}
+
+	if isCollectionItemType(*track, "artist") {
+		if url := normalizeShareURL(track.ExternalURL); url != "" {
+			return url
+		}
+	}
+	if url := normalizeShareURL(track.ArtistURL); url != "" {
+		return url
+	}
+	if url := urlFromExternalLinks(track.ExternalLinks, "artist"); url != "" {
+		return url
+	}
+	if url := templateShareURL(ext, "artist", firstNonEmptyString(track.ArtistID, collectionID(*track, "artist"))); url != "" {
+		return url
+	}
+	return ""
+}
+
+func collectionAlbumName(track ExtTrackMetadata) string {
+	if isCollectionItemType(track, "album") {
+		return track.Name
+	}
+	return track.AlbumName
+}
+
+func collectionArtistName(track ExtTrackMetadata) string {
+	if isCollectionItemType(track, "artist") {
+		return track.Name
+	}
+	return track.Artists
+}
+
+func collectionID(track ExtTrackMetadata, itemType string) string {
+	if isCollectionItemType(track, itemType) {
+		return track.ID
+	}
+	return ""
+}
+
+func isCollectionItemType(track ExtTrackMetadata, itemType string) bool {
+	return strings.EqualFold(strings.TrimSpace(track.ItemType), itemType)
+}
+
+func normalizeShareURL(value string) string {
+	trimmed := strings.TrimSpace(value)
+	if strings.HasPrefix(trimmed, "http://") || strings.HasPrefix(trimmed, "https://") {
+		return trimmed
+	}
+	return ""
+}
+
+func urlFromExternalLinks(links map[string]string, preferredKey string) string {
+	for key, value := range links {
+		if strings.Contains(strings.ToLower(key), preferredKey) {
+			if url := normalizeShareURL(value); url != "" {
+				return url
+			}
+		}
+	}
+	return ""
+}
+
+func templateShareURL(ext *loadedExtension, itemType string, id string) string {
+	if ext == nil || ext.Manifest == nil || ext.Manifest.Capabilities == nil {
+		return ""
+	}
+	id = stripProviderPrefix(strings.TrimSpace(id))
+	if id == "" {
+		return ""
+	}
+
+	templates, ok := ext.Manifest.Capabilities["shareUrlTemplates"].(map[string]interface{})
+	if !ok {
+		return ""
+	}
+	rawTemplate, ok := templates[itemType].(string)
+	if !ok {
+		return ""
+	}
+	rawTemplate = strings.TrimSpace(rawTemplate)
+	if rawTemplate == "" {
+		return ""
+	}
+	return strings.ReplaceAll(rawTemplate, "{id}", id)
+}
+
+func stripProviderPrefix(id string) string {
+	if index := strings.Index(id, ":"); index > 0 && index < len(id)-1 {
+		return id[index+1:]
+	}
+	return id
+}
+
+func firstNonEmptyString(values ...string) string {
+	for _, value := range values {
+		trimmed := strings.TrimSpace(value)
+		if trimmed != "" {
+			return trimmed
+		}
+	}
+	return ""
+}

go_backend/cross_extension_share_test.go

@@ -0,0 +1,100 @@
+package gobackend
+
+import "testing"
+
+func TestCrossExtensionShareUsesAlbumCollectionItems(t *testing.T) {
+	ext := &loadedExtension{
+		Manifest: &ExtensionManifest{
+			Capabilities: map[string]interface{}{
+				"shareUrlTemplates": map[string]interface{}{
+					"album": "https://music.apple.com/us/album/{id}",
+				},
+			},
+		},
+	}
+	tracks := []ExtTrackMetadata{
+		{
+			ID:       "1440783617",
+			Name:     "Nevermind",
+			Artists:  "Nirvana",
+			ItemType: "album",
+		},
+	}
+
+	best := bestAlbumTrack(tracks, "Nevermind", "Nirvana")
+	if best == nil {
+		t.Fatal("expected album collection item to match")
+	}
+	if url := resolveCollectionShareURL(ext, "album", best); url != "https://music.apple.com/us/album/1440783617" {
+		t.Fatalf("album share URL = %q", url)
+	}
+}
+
+func TestCrossExtensionShareUsesArtistCollectionItems(t *testing.T) {
+	ext := &loadedExtension{
+		Manifest: &ExtensionManifest{
+			Capabilities: map[string]interface{}{
+				"shareUrlTemplates": map[string]interface{}{
+					"artist": "https://music.youtube.com/browse/{id}",
+				},
+			},
+		},
+	}
+	tracks := []ExtTrackMetadata{
+		{
+			ID:       "UCrPe3hLA51968GwxHSZ1llw",
+			Name:     "Nirvana",
+			ItemType: "artist",
+		},
+	}
+
+	best := bestArtistTrack(tracks, "Nirvana")
+	if best == nil {
+		t.Fatal("expected artist collection item to match")
+	}
+	if url := resolveCollectionShareURL(ext, "artist", best); url != "https://music.youtube.com/browse/UCrPe3hLA51968GwxHSZ1llw" {
+		t.Fatalf("artist share URL = %q", url)
+	}
+}
+
+func TestCrossExtensionShareCacheKeyIsProviderOrderStable(t *testing.T) {
+	apple := &extensionProviderWrapper{
+		extension: &loadedExtension{
+			ID:        "apple",
+			SourceDir: "/extensions/apple",
+			Manifest:  &ExtensionManifest{DisplayName: "Apple Music"},
+		},
+	}
+	qobuz := &extensionProviderWrapper{
+		extension: &loadedExtension{
+			ID:        "qobuz",
+			SourceDir: "/extensions/qobuz",
+			Manifest:  &ExtensionManifest{DisplayName: "Qobuz"},
+		},
+	}
+
+	first := crossExtensionShareCacheKey("Nevermind", "Nirvana", "album", "spotify", []*extensionProviderWrapper{apple, qobuz})
+	second := crossExtensionShareCacheKey("Nevermind", "Nirvana", "album", "spotify", []*extensionProviderWrapper{qobuz, apple})
+	if first != second {
+		t.Fatalf("cache key should not depend on provider order:\n%s\n%s", first, second)
+	}
+}
+
+func TestCrossExtensionShareCacheableSkipsTransientErrors(t *testing.T) {
+	cacheable := []CrossExtensionShareResult{
+		{ExtensionID: "apple", Found: true, URL: "https://music.apple.com/us/album/1"},
+		{ExtensionID: "qobuz", Error: "album not found"},
+		{ExtensionID: "tidal", Error: "no results"},
+	}
+	if !crossExtensionShareResultsCacheable(cacheable) {
+		t.Fatal("expected found and deterministic not-found results to be cacheable")
+	}
+
+	transient := []CrossExtensionShareResult{
+		{ExtensionID: "apple", Found: true, URL: "https://music.apple.com/us/album/1"},
+		{ExtensionID: "qobuz", Error: "request failed: timeout"},
+	}
+	if crossExtensionShareResultsCacheable(transient) {
+		t.Fatal("expected transient extension errors to skip cache")
+	}
+}

go_backend/cue_parser.go

@@ -264,7 +264,7 @@ func ResolveCueAudioPath(cuePath string, cueFileName string) string {
 	}
 
 	baseName := strings.TrimSuffix(cueFileName, filepath.Ext(cueFileName))
-	commonExts := []string{".flac", ".wav", ".ape", ".mp3", ".ogg", ".wv", ".m4a"}
+	commonExts := []string{".flac", ".wav", ".aiff", ".aif", ".ape", ".mp3", ".ogg", ".wv", ".m4a"}
 	for _, ext := range commonExts {
 		candidate = filepath.Join(cueDir, baseName+ext)
 		if _, err := os.Stat(candidate); err == nil {

go_backend/exports.go

@@ -313,6 +313,7 @@ type DownloadResponse struct {
 	AlreadyExists               bool                    `json:"already_exists,omitempty"`
 	ActualBitDepth              int                     `json:"actual_bit_depth,omitempty"`
 	ActualSampleRate            int                     `json:"actual_sample_rate,omitempty"`
+	AudioCodec                  string                  `json:"audio_codec,omitempty"`
 	ActualExtension             string                  `json:"actual_extension,omitempty"`
 	ActualContainer             string                  `json:"actual_container,omitempty"`
 	RequiresContainerConversion bool                    `json:"requires_container_conversion,omitempty"`
@@ -342,6 +343,7 @@ type DownloadResult struct {
 	FilePath                    string
 	BitDepth                    int
 	SampleRate                  int
+	AudioCodec                  string
 	Title                       string
 	Artist                      string
 	Album                       string
@@ -377,6 +379,7 @@ type reEnrichRequest struct {
 	CoverURL      string   `json:"cover_url"`
 	MaxQuality    bool     `json:"max_quality"`
 	EmbedLyrics   bool     `json:"embed_lyrics"`
+	LyricsMode    string   `json:"lyrics_mode,omitempty"`
 	ArtistTagMode string   `json:"artist_tag_mode,omitempty"`
 	SpotifyID     string   `json:"spotify_id"`
 	TrackName     string   `json:"track_name"`
@@ -412,6 +415,21 @@ func (r *reEnrichRequest) shouldUpdateField(field string) bool {
 	return false
 }
 
+// lyricsEmbedEnabled reports whether lyrics should be written into the audio
+// file's tags. It mirrors the download path semantics: 'embed' and 'both' embed,
+// 'external' does not. An empty mode keeps the legacy behavior (embed) so older
+// callers that do not send lyrics_mode are unaffected.
+func (r *reEnrichRequest) lyricsEmbedEnabled() bool {
+	return strings.ToLower(strings.TrimSpace(r.LyricsMode)) != "external"
+}
+
+// lyricsSidecarEnabled reports whether a .lrc sidecar file should be written
+// next to the audio file. Only 'external' and 'both' request a sidecar.
+func (r *reEnrichRequest) lyricsSidecarEnabled() bool {
+	mode := strings.ToLower(strings.TrimSpace(r.LyricsMode))
+	return mode == "external" || mode == "both"
+}
+
 func applyReEnrichTrackMetadata(req *reEnrichRequest, track ExtTrackMetadata) {
 	if req == nil {
 		return
@@ -576,7 +594,7 @@ func buildReEnrichFFmpegMetadata(req *reEnrichRequest, lyricsLRC string) map[str
 		}
 	}
 	if req.shouldUpdateField("lyrics") {
-		if lyricsLRC != "" {
+		if lyricsLRC != "" && req.lyricsEmbedEnabled() {
 			metadata["LYRICS"] = lyricsLRC
 			metadata["UNSYNCEDLYRICS"] = lyricsLRC
 		}
@@ -592,12 +610,24 @@ func selectBestReEnrichTrack(req reEnrichRequest, tracks []ExtTrackMetadata) *Ex
 	downloadReq := reEnrichDownloadRequest(req)
 	currentISRC := strings.TrimSpace(req.ISRC)
 	currentAlbum := strings.TrimSpace(req.AlbumName)
+	effectiveTrackName := req.TrackName
+	if isPlaceholderReEnrichValue(effectiveTrackName) {
+		effectiveTrackName = ""
+	}
+	effectiveArtistName := req.ArtistName
+	if isPlaceholderReEnrichValue(effectiveArtistName) {
+		effectiveArtistName = ""
+	}
 	var best *ExtTrackMetadata
 	bestScore := -1 << 30
 
 	for i := range tracks {
 		track := &tracks[i]
 		score := 0
+		exactISRCMatch := currentISRC != "" && strings.EqualFold(currentISRC, strings.TrimSpace(track.ISRC))
+		titleMatches := effectiveTrackName != "" && track.Name != "" && titlesMatch(effectiveTrackName, track.Name)
+		artistMatches := effectiveArtistName != "" && track.Artists != "" && artistsMatch(effectiveArtistName, track.Artists)
+		albumMatches := currentAlbum != "" && track.AlbumName != "" && titlesMatch(currentAlbum, track.AlbumName)
 
 		resolved := resolvedTrackInfo{
 			Title:      track.Name,
@@ -605,22 +635,39 @@ func selectBestReEnrichTrack(req reEnrichRequest, tracks []ExtTrackMetadata) *Ex
 			ISRC:       track.ISRC,
 			Duration:   track.DurationMS / 1000,
 		}
-		if trackMatchesRequest(downloadReq, resolved, "ReEnrich") {
+		verified := trackMatchesRequest(downloadReq, resolved, "ReEnrich")
+
+		if !exactISRCMatch {
+			if effectiveTrackName != "" && !titleMatches {
+				continue
+			}
+			if effectiveArtistName != "" && !artistMatches {
+				continue
+			}
+			if effectiveTrackName == "" && effectiveArtistName == "" && currentAlbum != "" && !albumMatches {
+				continue
+			}
+			if effectiveTrackName == "" && effectiveArtistName == "" && currentAlbum == "" && !verified {
+				continue
+			}
+		}
+
+		if verified {
 			score += 2000
 		}
 
-		if currentISRC != "" && strings.EqualFold(currentISRC, strings.TrimSpace(track.ISRC)) {
+		if exactISRCMatch {
 			score += 10000
 		}
-		if req.TrackName != "" && track.Name != "" && titlesMatch(req.TrackName, track.Name) {
+		if titleMatches {
 			score += 400
 		}
-		if req.ArtistName != "" && track.Artists != "" && artistsMatch(req.ArtistName, track.Artists) {
+		if artistMatches {
 			score += 320
 		}
 		if currentAlbum != "" && track.AlbumName != "" {
 			switch {
-			case titlesMatch(currentAlbum, track.AlbumName):
+			case albumMatches:
 				score += 120
 			case strings.Contains(strings.ToLower(track.AlbumName), strings.ToLower(currentAlbum)),
 				strings.Contains(strings.ToLower(currentAlbum), strings.ToLower(track.AlbumName)):
@@ -863,6 +910,7 @@ func buildDownloadSuccessResponse(
 		AlreadyExists:               alreadyExists,
 		ActualBitDepth:              result.BitDepth,
 		ActualSampleRate:            result.SampleRate,
+		AudioCodec:                  result.AudioCodec,
 		ActualExtension:             result.ActualExtension,
 		ActualContainer:             result.ActualContainer,
 		RequiresContainerConversion: result.RequiresContainerConversion,
@@ -920,7 +968,12 @@ func enrichResultQualityFromFile(result *DownloadResult) {
 	if qErr == nil {
 		result.BitDepth = quality.BitDepth
 		result.SampleRate = quality.SampleRate
-		GoLog("[Download] Actual quality from file: %d-bit/%dHz\n", quality.BitDepth, quality.SampleRate)
+		result.AudioCodec = quality.Codec
+		if quality.Codec != "" {
+			GoLog("[Download] Actual quality from file: %s %d-bit/%dHz\n", quality.Codec, quality.BitDepth, quality.SampleRate)
+		} else {
+			GoLog("[Download] Actual quality from file: %d-bit/%dHz\n", quality.BitDepth, quality.SampleRate)
+		}
 		return
 	}
 
@@ -1101,12 +1154,14 @@ func CleanupConnections() {
 func ReadFileMetadata(filePath string) (string, error) {
 	lower := strings.ToLower(filePath)
 	isFlac := strings.HasSuffix(lower, ".flac")
-	isM4A := strings.HasSuffix(lower, ".m4a") || strings.HasSuffix(lower, ".aac")
+	isM4A := strings.HasSuffix(lower, ".m4a") || strings.HasSuffix(lower, ".mp4") || strings.HasSuffix(lower, ".aac")
 	isMp3 := strings.HasSuffix(lower, ".mp3")
 	isOgg := strings.HasSuffix(lower, ".opus") || strings.HasSuffix(lower, ".ogg")
 	isApe := strings.HasSuffix(lower, ".ape")
 	isWv := strings.HasSuffix(lower, ".wv")
 	isMpc := strings.HasSuffix(lower, ".mpc")
+	isWav := strings.HasSuffix(lower, ".wav")
+	isAiff := strings.HasSuffix(lower, ".aiff") || strings.HasSuffix(lower, ".aif") || strings.HasSuffix(lower, ".aifc")
 
 	result := map[string]interface{}{
 		"title":        "",
@@ -1126,9 +1181,13 @@ func ReadFileMetadata(filePath string) (string, error) {
 		"composer":     "",
 		"comment":      "",
 		"duration":     0,
+		"format":       "",
+		"audio_codec":  "",
 	}
 
 	if isFlac {
+		result["format"] = "flac"
+		result["audio_codec"] = "flac"
 		metadata, err := ReadMetadata(filePath)
 		if err != nil {
 			// File may have wrong extension (e.g. opus saved as .flac).
@@ -1161,6 +1220,8 @@ func ReadFileMetadata(filePath string) (string, error) {
 						result["bitrate"] = quality.Bitrate / 1000
 					}
 				}
+				result["format"] = "opus"
+				result["audio_codec"] = "opus"
 			} else {
 				return "", fmt.Errorf("failed to read metadata: %w", err)
 			}
@@ -1190,12 +1251,16 @@ func ReadFileMetadata(filePath string) (string, error) {
 			if qualityErr == nil {
 				result["bit_depth"] = quality.BitDepth
 				result["sample_rate"] = quality.SampleRate
+				if quality.Codec != "" {
+					result["audio_codec"] = quality.Codec
+				}
 				if quality.SampleRate > 0 && quality.TotalSamples > 0 {
 					result["duration"] = int(quality.TotalSamples / int64(quality.SampleRate))
 				}
 			}
 		}
 	} else if isM4A {
+		result["format"] = "m4a"
 		meta, err := ReadM4ATags(filePath)
 		if err == nil && meta != nil {
 			result["title"] = meta.Title
@@ -1227,8 +1292,17 @@ func ReadFileMetadata(filePath string) (string, error) {
 			result["bit_depth"] = quality.BitDepth
 			result["sample_rate"] = quality.SampleRate
 			result["duration"] = quality.Duration
+			result["audio_codec"] = quality.Codec
+			if format := libraryFormatForM4ACodec(quality.Codec); format != "" {
+				result["format"] = format
+			}
+			if quality.Bitrate > 0 && !isLosslessLibraryFormat(fmt.Sprint(result["format"])) {
+				result["bitrate"] = quality.Bitrate
+			}
 		}
 	} else if isMp3 {
+		result["format"] = "mp3"
+		result["audio_codec"] = "mp3"
 		meta, err := ReadID3Tags(filePath)
 		if err == nil && meta != nil {
 			result["title"] = meta.Title
@@ -1265,6 +1339,8 @@ func ReadFileMetadata(filePath string) (string, error) {
 			}
 		}
 	} else if isOgg {
+		result["format"] = "opus"
+		result["audio_codec"] = "opus"
 		meta, err := ReadOggVorbisComments(filePath)
 		if err == nil && meta != nil {
 			result["title"] = meta.Title
@@ -1300,6 +1376,8 @@ func ReadFileMetadata(filePath string) (string, error) {
 			}
 		}
 	} else if isApe || isWv || isMpc {
+		result["format"] = strings.TrimPrefix(filepath.Ext(filePath), ".")
+		result["audio_codec"] = result["format"]
 		// APE, WavPack, Musepack: read APEv2 tags
 		apeTag, apeErr := ReadAPETags(filePath)
 		if apeErr == nil && apeTag != nil {
@@ -1330,6 +1408,51 @@ func ReadFileMetadata(filePath string) (string, error) {
 				result["replaygain_album_peak"] = meta.ReplayGainAlbumPeak
 			}
 		}
+	} else if isWav || isAiff {
+		var meta *AudioMetadata
+		var quality *WAVQuality
+		var qualityErr error
+		if isAiff {
+			result["format"] = "aiff"
+			result["audio_codec"] = "pcm"
+			meta, _ = ReadAIFFTags(filePath)
+			quality, qualityErr = GetAIFFQuality(filePath)
+		} else {
+			result["format"] = "wav"
+			result["audio_codec"] = "pcm"
+			meta, _ = ReadWAVTags(filePath)
+			quality, qualityErr = GetWAVQuality(filePath)
+		}
+		if meta != nil {
+			result["title"] = meta.Title
+			result["artist"] = meta.Artist
+			result["album"] = meta.Album
+			result["album_artist"] = meta.AlbumArtist
+			result["date"] = meta.Date
+			if meta.Date == "" {
+				result["date"] = meta.Year
+			}
+			result["track_number"] = meta.TrackNumber
+			result["total_tracks"] = meta.TotalTracks
+			result["disc_number"] = meta.DiscNumber
+			result["total_discs"] = meta.TotalDiscs
+			result["isrc"] = meta.ISRC
+			result["lyrics"] = meta.Lyrics
+			result["genre"] = meta.Genre
+			result["label"] = meta.Label
+			result["copyright"] = meta.Copyright
+			result["composer"] = meta.Composer
+			result["comment"] = meta.Comment
+			result["replaygain_track_gain"] = meta.ReplayGainTrackGain
+			result["replaygain_track_peak"] = meta.ReplayGainTrackPeak
+			result["replaygain_album_gain"] = meta.ReplayGainAlbumGain
+			result["replaygain_album_peak"] = meta.ReplayGainAlbumPeak
+		}
+		if qualityErr == nil && quality != nil {
+			result["bit_depth"] = quality.BitDepth
+			result["sample_rate"] = quality.SampleRate
+			result["duration"] = quality.Duration
+		}
 	} else {
 		return "", fmt.Errorf("unsupported file format: %s", filePath)
 	}
@@ -1398,8 +1521,23 @@ func EditFileMetadata(filePath, metadataJSON string) (string, error) {
 	isFlac := strings.HasSuffix(lower, ".flac")
 	isApeFile := strings.HasSuffix(lower, ".ape") || strings.HasSuffix(lower, ".wv") || strings.HasSuffix(lower, ".mpc")
 	isM4AFile := strings.HasSuffix(lower, ".m4a") || strings.HasSuffix(lower, ".mp4") || strings.HasSuffix(lower, ".m4b")
+	isWavFile := strings.HasSuffix(lower, ".wav")
+	isAiffFile := strings.HasSuffix(lower, ".aiff") || strings.HasSuffix(lower, ".aif") || strings.HasSuffix(lower, ".aifc")
 	coverPath := strings.TrimSpace(fields["cover_path"])
 
+	if hasOnlyM4AReplayGainFields(fields) && (isM4AFile || isMP4ContainerFile(filePath)) {
+		if err := EditM4AReplayGain(filePath, fields); err != nil {
+			return "", fmt.Errorf("failed to write M4A metadata: %w", err)
+		}
+
+		resp := map[string]any{
+			"success": true,
+			"method":  "native_m4a_replaygain",
+		}
+		jsonBytes, _ := json.Marshal(resp)
+		return string(jsonBytes), nil
+	}
+
 	if isFlac {
 		if err := EditFlacFields(filePath, fields); err != nil {
 			return "", fmt.Errorf("failed to write FLAC metadata: %w", err)
@@ -1413,6 +1551,24 @@ func EditFileMetadata(filePath, metadataJSON string) (string, error) {
 		return string(jsonBytes), nil
 	}
 
+	// WAV / AIFF: write tags into an embedded ID3v2.4 chunk natively.
+	if isWavFile {
+		if err := WriteWAVTags(filePath, fields); err != nil {
+			return "", fmt.Errorf("failed to write WAV metadata: %w", err)
+		}
+		resp := map[string]any{"success": true, "method": "native_wav"}
+		jsonBytes, _ := json.Marshal(resp)
+		return string(jsonBytes), nil
+	}
+	if isAiffFile {
+		if err := WriteAIFFTags(filePath, fields); err != nil {
+			return "", fmt.Errorf("failed to write AIFF metadata: %w", err)
+		}
+		resp := map[string]any{"success": true, "method": "native_aiff"}
+		jsonBytes, _ := json.Marshal(resp)
+		return string(jsonBytes), nil
+	}
+
 	// APE/WV/MPC: write APEv2 tags natively
 	if isApeFile {
 		trackNum := 0
@@ -1510,19 +1666,6 @@ func EditFileMetadata(filePath, metadataJSON string) (string, error) {
 		return string(jsonBytes), nil
 	}
 
-	if isM4AFile && hasOnlyM4AReplayGainFields(fields) {
-		if err := EditM4AReplayGain(filePath, fields); err != nil {
-			return "", fmt.Errorf("failed to write M4A metadata: %w", err)
-		}
-
-		resp := map[string]any{
-			"success": true,
-			"method":  "native_m4a_replaygain",
-		}
-		jsonBytes, _ := json.Marshal(resp)
-		return string(jsonBytes), nil
-	}
-
 	resp := map[string]any{
 		"success": true,
 		"method":  "ffmpeg",
@@ -1532,6 +1675,21 @@ func EditFileMetadata(filePath, metadataJSON string) (string, error) {
 	return string(jsonBytes), nil
 }
 
+func isMP4ContainerFile(filePath string) bool {
+	f, err := os.Open(filePath)
+	if err != nil {
+		return false
+	}
+	defer f.Close()
+
+	header := make([]byte, 12)
+	n, err := f.Read(header)
+	if err != nil || n < 8 {
+		return false
+	}
+	return string(header[4:8]) == "ftyp"
+}
+
 func hasOnlyM4AReplayGainFields(fields map[string]string) bool {
 	allowed := map[string]struct{}{
 		"replaygain_track_gain": {},
@@ -1660,9 +1818,13 @@ func GetLyricsLRCWithSource(spotifyID, trackName, artistName string, filePath st
 	if filePath != "" {
 		lyrics, err := ExtractLyrics(filePath)
 		if err == nil && lyrics != "" {
+			source := extractLyricsSourceFromLRC(lyrics)
+			if source == "" {
+				source = "Embedded"
+			}
 			result := map[string]interface{}{
 				"lyrics":       lyrics,
-				"source":       "Embedded",
+				"source":       source,
 				"sync_type":    "EMBEDDED",
 				"instrumental": false,
 			}
@@ -1865,6 +2027,11 @@ func normalizeExtensionTrackMetadataMap(
 		"artists":       track.Artists,
 		"album_name":    track.AlbumName,
 		"album_artist":  track.AlbumArtist,
+		"album_id":      track.AlbumID,
+		"album_url":     track.AlbumURL,
+		"artist_id":     track.ArtistID,
+		"artist_url":    track.ArtistURL,
+		"external_urls": track.ExternalURL,
 		"duration_ms":   track.DurationMS,
 		"images":        coverURL,
 		"cover_url":     coverURL,
@@ -2283,37 +2450,7 @@ func GetTidalURLFromDeezerTrack(deezerTrackID string) (string, error) {
 }
 
 func errorResponse(msg string) (string, error) {
-	errorType := "unknown"
-	lowerMsg := strings.ToLower(msg)
-
-	if strings.Contains(lowerMsg, "isp blocking") ||
-		strings.Contains(lowerMsg, "try using vpn") ||
-		strings.Contains(lowerMsg, "change dns") {
-		errorType = "isp_blocked"
-	} else if strings.Contains(lowerMsg, "cancel") {
-		errorType = "cancelled"
-	} else if strings.Contains(lowerMsg, "permission") ||
-		strings.Contains(lowerMsg, "operation not permitted") ||
-		strings.Contains(lowerMsg, "access denied") ||
-		strings.Contains(lowerMsg, "failed to create file") ||
-		strings.Contains(lowerMsg, "failed to create directory") {
-		errorType = "permission"
-	} else if strings.Contains(lowerMsg, "not found") ||
-		strings.Contains(lowerMsg, "not available") ||
-		strings.Contains(lowerMsg, "no results") ||
-		strings.Contains(lowerMsg, "track not found") ||
-		strings.Contains(lowerMsg, "all services failed") {
-		errorType = "not_found"
-	} else if strings.Contains(lowerMsg, "rate limit") ||
-		strings.Contains(lowerMsg, "429") ||
-		strings.Contains(lowerMsg, "too many requests") {
-		errorType = "rate_limit"
-	} else if strings.Contains(lowerMsg, "network") ||
-		strings.Contains(lowerMsg, "connection") ||
-		strings.Contains(lowerMsg, "timeout") ||
-		strings.Contains(lowerMsg, "dial") {
-		errorType = "network"
-	}
+	errorType := classifyDownloadErrorType(msg)
 
 	resp := DownloadResponse{
 		Success:   false,
@@ -2324,6 +2461,41 @@ func errorResponse(msg string) (string, error) {
 	return string(jsonBytes), nil
 }
 
+func classifyDownloadErrorType(msg string) string {
+	lowerMsg := strings.ToLower(msg)
+
+	if strings.Contains(lowerMsg, "isp blocking") ||
+		strings.Contains(lowerMsg, "try using vpn") ||
+		strings.Contains(lowerMsg, "change dns") {
+		return "isp_blocked"
+	} else if strings.Contains(lowerMsg, "cancel") {
+		return "cancelled"
+	} else if strings.Contains(lowerMsg, "rate limit") ||
+		strings.Contains(lowerMsg, "429") ||
+		strings.Contains(lowerMsg, "too many requests") {
+		return "rate_limit"
+	} else if strings.Contains(lowerMsg, "permission") ||
+		strings.Contains(lowerMsg, "operation not permitted") ||
+		strings.Contains(lowerMsg, "access denied") ||
+		strings.Contains(lowerMsg, "failed to create file") ||
+		strings.Contains(lowerMsg, "failed to create directory") {
+		return "permission"
+	} else if strings.Contains(lowerMsg, "not found") ||
+		strings.Contains(lowerMsg, "not available") ||
+		strings.Contains(lowerMsg, "no results") ||
+		strings.Contains(lowerMsg, "track not found") ||
+		strings.Contains(lowerMsg, "all services failed") {
+		return "not_found"
+	} else if strings.Contains(lowerMsg, "network") ||
+		strings.Contains(lowerMsg, "connection") ||
+		strings.Contains(lowerMsg, "timeout") ||
+		strings.Contains(lowerMsg, "dial") {
+		return "network"
+	}
+
+	return "unknown"
+}
+
 func DownloadCoverToFile(coverURL string, outputPath string, maxQuality bool) error {
 	if coverURL == "" {
 		return fmt.Errorf("no cover URL provided")
@@ -2670,7 +2842,9 @@ func ReEnrichFile(requestJSON string) (string, error) {
 			metadata.ISRC = req.ISRC
 		}
 		if req.shouldUpdateField("lyrics") {
-			metadata.Lyrics = lyricsLRC
+			if req.lyricsEmbedEnabled() {
+				metadata.Lyrics = lyricsLRC
+			}
 		}
 		if req.shouldUpdateField("extra") {
 			metadata.Genre = req.Genre
@@ -2705,6 +2879,11 @@ func ReEnrichFile(requestJSON string) (string, error) {
 			"method":            "native",
 			"success":           true,
 			"enriched_metadata": enrichedMeta,
+			"lyrics":            lyricsLRC,
+			"write_external_lrc": req.EmbedLyrics &&
+				req.shouldUpdateField("lyrics") &&
+				req.lyricsSidecarEnabled() &&
+				strings.TrimSpace(lyricsLRC) != "",
 		}
 		jsonBytes, _ := json.Marshal(result)
 		return string(jsonBytes), nil
@@ -2720,6 +2899,10 @@ func ReEnrichFile(requestJSON string) (string, error) {
 		"lyrics":            lyricsLRC,
 		"enriched_metadata": enrichedMeta,
 		"metadata":          ffmpegMetadata,
+		"write_external_lrc": req.EmbedLyrics &&
+			req.shouldUpdateField("lyrics") &&
+			req.lyricsSidecarEnabled() &&
+			strings.TrimSpace(lyricsLRC) != "",
 	}
 
 	jsonBytes, _ := json.Marshal(result)

go_backend/exports_supplement_test.go

@@ -11,6 +11,26 @@ import (
 	"time"
 )
 
+func TestDownloadErrorClassificationPrioritizesRateLimit(t *testing.T) {
+	got := classifyDownloadErrorType("All providers failed. Last error: HTTP status 429: too many requests")
+	if got != "rate_limit" {
+		t.Fatalf("expected rate_limit, got %q", got)
+	}
+
+	responseJSON, err := errorResponse("All services failed. Last error: rate limit exceeded")
+	if err != nil {
+		t.Fatalf("errorResponse returned error: %v", err)
+	}
+
+	var response DownloadResponse
+	if err := json.Unmarshal([]byte(responseJSON), &response); err != nil {
+		t.Fatalf("invalid response JSON: %v", err)
+	}
+	if response.ErrorType != "rate_limit" {
+		t.Fatalf("expected rate_limit response, got %q", response.ErrorType)
+	}
+}
+
 func TestExportsJSONWrappersAndExtensionManagerSurface(t *testing.T) {
 	dir := t.TempDir()
 	dataDir := filepath.Join(dir, "data")
@@ -85,6 +105,14 @@ func TestExportsJSONWrappersAndExtensionManagerSurface(t *testing.T) {
 	if response, err := EditFileMetadata(filepath.Join(dir, "edit.mp3"), editJSON); err != nil || !strings.Contains(response, "ffmpeg") {
 		t.Fatalf("EditFileMetadata ffmpeg = %q/%v", response, err)
 	}
+	misnamedM4APath := filepath.Join(dir, "misnamed.flac")
+	if err := os.WriteFile(misnamedM4APath, buildM4AFileWithIlst(buildM4ATextTag("\xa9nam", "Misnamed"), true), 0600); err != nil {
+		t.Fatal(err)
+	}
+	replayGainJSON := `{"replaygain_track_gain":"-1 dB","replaygain_track_peak":"0.9"}`
+	if response, err := EditFileMetadata(misnamedM4APath, replayGainJSON); err != nil || !strings.Contains(response, "native_m4a_replaygain") {
+		t.Fatalf("EditFileMetadata misnamed m4a replaygain = %q/%v", response, err)
+	}
 	if _, err := EditFileMetadata(apePath, `not-json`); err == nil {
 		t.Fatal("expected invalid metadata JSON")
 	}

go_backend/exports_test.go

@@ -407,6 +407,90 @@ func TestSelectBestReEnrichTrackPrefersCandidateWithReleaseDate(t *testing.T) {
 	}
 }
 
+func TestSelectBestReEnrichTrackRejectsMismatchedSearchResults(t *testing.T) {
+	req := reEnrichRequest{
+		TrackName:  "Song Title",
+		ArtistName: "Artist Name",
+		AlbumName:  "Album Name",
+		DurationMs: 180000,
+	}
+
+	tracks := []ExtTrackMetadata{
+		{
+			ID:          "wrong-rich-metadata",
+			Name:        "Different Song",
+			Artists:     "Different Artist",
+			AlbumName:   "Album Name",
+			DurationMS:  180000,
+			ReleaseDate: "2024-03-09",
+			TrackNumber: 4,
+			DiscNumber:  1,
+			ISRC:        "WRONG1234567",
+			ProviderID:  "deezer",
+		},
+	}
+
+	if best := selectBestReEnrichTrack(req, tracks); best != nil {
+		t.Fatalf("selected track = %q, want no match", best.ID)
+	}
+}
+
+func TestSelectBestReEnrichTrackAllowsExactISRCDespiteMetadataMismatch(t *testing.T) {
+	req := reEnrichRequest{
+		TrackName:  "Song Title",
+		ArtistName: "Artist Name",
+		ISRC:       "USRC17607839",
+		DurationMs: 999999000,
+	}
+
+	tracks := []ExtTrackMetadata{
+		{
+			ID:         "same-isrc",
+			Name:       "Different Song",
+			Artists:    "Different Artist",
+			DurationMS: 180000,
+			ISRC:       "USRC17607839",
+			ProviderID: "deezer",
+		},
+	}
+
+	best := selectBestReEnrichTrack(req, tracks)
+	if best == nil {
+		t.Fatal("expected exact ISRC candidate to be selected")
+	}
+	if best.ID != "same-isrc" {
+		t.Fatalf("selected track = %q, want exact ISRC candidate", best.ID)
+	}
+}
+
+func TestSelectBestReEnrichTrackPlaceholderFallsBackToAlbum(t *testing.T) {
+	req := reEnrichRequest{
+		TrackName:  "Unknown Title",
+		ArtistName: "Unknown Artist",
+		AlbumName:  "Harry Styles",
+		DurationMs: 180000,
+	}
+
+	tracks := []ExtTrackMetadata{
+		{
+			ID:         "album-match",
+			Name:       "Sign of the Times",
+			Artists:    "Harry Styles",
+			AlbumName:  "Harry Styles",
+			DurationMS: 180000,
+			ProviderID: "deezer",
+		},
+	}
+
+	best := selectBestReEnrichTrack(req, tracks)
+	if best == nil {
+		t.Fatal("expected album-matching candidate to be selected when title/artist are placeholders")
+	}
+	if best.ID != "album-match" {
+		t.Fatalf("selected track = %q, want album-match", best.ID)
+	}
+}
+
 func TestBuildReEnrichFFmpegMetadataOmitsEmptyFields(t *testing.T) {
 	req := reEnrichRequest{
 		TrackName:   "Song",

go_backend/extension_health.go

@@ -8,12 +8,14 @@ import (
 	"net/http"
 	"net/url"
 	"strings"
+	"sync"
 	"time"
 )
 
 const (
 	extensionHealthDefaultTimeout = 4 * time.Second
 	extensionHealthMaxBodyBytes   = 64 * 1024
+	extensionHealthDefaultCache   = 60 * time.Second
 )
 
 type ExtensionHealthResult struct {
@@ -38,6 +40,16 @@ type ExtensionHealthCheckResult struct {
 	CheckedAt  string `json:"checked_at"`
 }
 
+type cachedExtensionHealthResult struct {
+	result    ExtensionHealthResult
+	expiresAt time.Time
+}
+
+var (
+	extensionHealthCacheMu sync.Mutex
+	extensionHealthCache   = map[string]cachedExtensionHealthResult{}
+)
+
 func CheckExtensionHealthJSON(extensionID string) (string, error) {
 	manager := getExtensionManager()
 	ext, err := manager.GetExtension(extensionID)
@@ -53,6 +65,38 @@ func CheckExtensionHealthJSON(extensionID string) (string, error) {
 	return string(bytes), nil
 }
 
+func CheckExtensionHealthCached(ext *loadedExtension) ExtensionHealthResult {
+	if ext == nil || ext.Manifest == nil || len(ext.Manifest.ServiceHealth) == 0 {
+		return CheckExtensionHealth(ext)
+	}
+
+	cacheKey := strings.TrimSpace(ext.ID)
+	if cacheKey == "" {
+		return CheckExtensionHealth(ext)
+	}
+
+	now := time.Now()
+	extensionHealthCacheMu.Lock()
+	cached, ok := extensionHealthCache[cacheKey]
+	if ok && now.Before(cached.expiresAt) {
+		extensionHealthCacheMu.Unlock()
+		return cached.result
+	}
+	extensionHealthCacheMu.Unlock()
+
+	result := CheckExtensionHealth(ext)
+	ttl := extensionHealthCacheTTL(ext.Manifest.ServiceHealth)
+
+	extensionHealthCacheMu.Lock()
+	extensionHealthCache[cacheKey] = cachedExtensionHealthResult{
+		result:    result,
+		expiresAt: now.Add(ttl),
+	}
+	extensionHealthCacheMu.Unlock()
+
+	return result
+}
+
 func CheckExtensionHealth(ext *loadedExtension) ExtensionHealthResult {
 	now := time.Now().UTC().Format(time.RFC3339)
 	result := ExtensionHealthResult{
@@ -98,6 +142,20 @@ func CheckExtensionHealth(ext *loadedExtension) ExtensionHealthResult {
 	return result
 }
 
+func extensionHealthCacheTTL(checks []ExtensionHealthCheck) time.Duration {
+	ttl := extensionHealthDefaultCache
+	for _, check := range checks {
+		if check.CacheTTLSeconds <= 0 {
+			continue
+		}
+		checkTTL := time.Duration(check.CacheTTLSeconds) * time.Second
+		if checkTTL < ttl {
+			ttl = checkTTL
+		}
+	}
+	return ttl
+}
+
 func runExtensionHealthCheck(manifest *ExtensionManifest, check ExtensionHealthCheck) ExtensionHealthCheckResult {
 	method := strings.ToUpper(strings.TrimSpace(check.Method))
 	if method == "" {

go_backend/extension_manager.go

@@ -118,7 +118,11 @@ func (ext *loadedExtension) lockReadyVM() (*goja.Runtime, error) {
 }
 
 type extensionManager struct {
-	mu            sync.RWMutex
+	mu sync.RWMutex
+	// mutationMu serializes install/upgrade/remove (heavy FS + goja VM
+	// teardown/reload), which are not safe to run concurrently. Acquired before
+	// m.mu; "*Locked" helpers assume it is held.
+	mutationMu    sync.Mutex
 	extensions    map[string]*loadedExtension
 	extensionsDir string
 	dataDir       string
@@ -156,6 +160,12 @@ func (m *extensionManager) SetDirectories(extensionsDir, dataDir string) error {
 }
 
 func (m *extensionManager) LoadExtensionFromFile(filePath string) (*loadedExtension, error) {
+	m.mutationMu.Lock()
+	defer m.mutationMu.Unlock()
+	return m.loadExtensionFromFileLocked(filePath)
+}
+
+func (m *extensionManager) loadExtensionFromFileLocked(filePath string) (*loadedExtension, error) {
 	if !strings.HasSuffix(strings.ToLower(filePath), ".spotiflac-ext") {
 		return nil, fmt.Errorf("invalid file format: please select a .spotiflac-ext file")
 	}
@@ -212,7 +222,7 @@ func (m *extensionManager) LoadExtensionFromFile(filePath string) (*loadedExtens
 	if exists {
 		versionCompare := compareVersions(manifest.Version, existingVersion)
 		if versionCompare > 0 {
-			return m.UpgradeExtension(filePath)
+			return m.upgradeExtensionLocked(filePath)
 		} else if versionCompare == 0 {
 			return nil, fmt.Errorf("extension '%s' v%s is already installed", existingDisplayName, existingVersion)
 		} else {
@@ -367,8 +377,8 @@ func newIsolatedExtensionRuntime(ext *loadedExtension) (*goja.Runtime, *extensio
 		jar, _ := newSimpleCookieJar()
 		runtime.cookieJar = jar
 	}
-	runtime.httpClient = newExtensionHTTPClient(ext, runtime.cookieJar, extensionHTTPTimeout(ext, 30*time.Second))
-	runtime.downloadClient = newExtensionHTTPClient(ext, runtime.cookieJar, DownloadTimeout)
+	runtime.httpClient = newExtensionHTTPClient(ext, runtime.cookieJar, extensionHTTPTimeout(ext, 30*time.Second), true)
+	runtime.downloadClient = newExtensionHTTPClient(ext, runtime.cookieJar, DownloadTimeout, false)
 	runtime.RegisterAPIs(vm)
 	runtime.RegisterGoBackendAPIs(vm)
 
@@ -736,6 +746,9 @@ func (m *extensionManager) loadExtensionFromDirectory(dirPath string) (*loadedEx
 }
 
 func (m *extensionManager) RemoveExtension(extensionID string) error {
+	m.mutationMu.Lock()
+	defer m.mutationMu.Unlock()
+
 	ext, err := m.GetExtension(extensionID)
 	if err != nil {
 		return err
@@ -756,6 +769,12 @@ func (m *extensionManager) RemoveExtension(extensionID string) error {
 
 // Only allows upgrades (new version > current version), not downgrades
 func (m *extensionManager) UpgradeExtension(filePath string) (*loadedExtension, error) {
+	m.mutationMu.Lock()
+	defer m.mutationMu.Unlock()
+	return m.upgradeExtensionLocked(filePath)
+}
+
+func (m *extensionManager) upgradeExtensionLocked(filePath string) (*loadedExtension, error) {
 	if !strings.HasSuffix(strings.ToLower(filePath), ".spotiflac-ext") {
 		return nil, fmt.Errorf("invalid file format: please select a .spotiflac-ext file")
 	}

go_backend/extension_providers.go

@@ -22,6 +22,11 @@ type ExtTrackMetadata struct {
 	Artists     string `json:"artists"`
 	AlbumName   string `json:"album_name"`
 	AlbumArtist string `json:"album_artist,omitempty"`
+	AlbumID     string `json:"album_id,omitempty"`
+	AlbumURL    string `json:"album_url,omitempty"`
+	ArtistID    string `json:"artist_id,omitempty"`
+	ArtistURL   string `json:"artist_url,omitempty"`
+	ExternalURL string `json:"external_urls,omitempty"`
 	DurationMS  int    `json:"duration_ms"`
 	CoverURL    string `json:"cover_url,omitempty"`
 	Images      string `json:"images,omitempty"`
@@ -236,6 +241,7 @@ func normalizeExtensionDownloadResult(result *ExtDownloadResult) (DownloadResult
 		FilePath:                    strings.TrimSpace(result.FilePath),
 		BitDepth:                    result.BitDepth,
 		SampleRate:                  result.SampleRate,
+		AudioCodec:                  strings.TrimSpace(result.AudioCodec),
 		Title:                       result.Title,
 		Artist:                      result.Artist,
 		Album:                       result.Album,
@@ -376,6 +382,64 @@ func shouldStopProviderFallback(availability *ExtAvailabilityResult) bool {
 	return availability != nil && availability.SkipFallback
 }
 
+func fallbackRuntimeHealthStatus(ext *loadedExtension) string {
+	if ext == nil || ext.Manifest == nil || len(ext.Manifest.ServiceHealth) == 0 {
+		return "unknown"
+	}
+
+	status := strings.ToLower(strings.TrimSpace(CheckExtensionHealthCached(ext).Status))
+	switch status {
+	case "online", "degraded", "offline":
+		return status
+	default:
+		return "unknown"
+	}
+}
+
+func prioritizeFallbackProvidersByHealth(priority []string, extManager *extensionManager, sourceProvider string) []string {
+	if len(priority) == 0 || extManager == nil {
+		return priority
+	}
+
+	online := make([]string, 0, len(priority))
+	degraded := make([]string, 0, len(priority))
+	unknown := make([]string, 0, len(priority))
+
+	for _, rawProviderID := range priority {
+		providerID := strings.TrimSpace(rawProviderID)
+		if providerID == "" {
+			continue
+		}
+		if strings.EqualFold(providerID, sourceProvider) || !isExtensionFallbackAllowed(providerID) {
+			unknown = append(unknown, providerID)
+			continue
+		}
+
+		ext, err := extManager.GetExtension(providerID)
+		if err != nil || ext == nil || !ext.Enabled || ext.Error != "" || ext.Manifest == nil || !ext.Manifest.IsDownloadProvider() {
+			unknown = append(unknown, providerID)
+			continue
+		}
+
+		switch fallbackRuntimeHealthStatus(ext) {
+		case "online":
+			online = append(online, providerID)
+		case "degraded":
+			degraded = append(degraded, providerID)
+		case "offline":
+			GoLog("[DownloadWithExtensionFallback] Skipping extension provider %s (service health offline)\n", providerID)
+		default:
+			unknown = append(unknown, providerID)
+		}
+	}
+
+	result := make([]string, 0, len(online)+len(degraded)+len(unknown))
+	result = append(result, online...)
+	result = append(result, degraded...)
+	result = append(result, unknown...)
+	return result
+}
+
 func resolveExtensionAvailabilityReason(availability *ExtAvailabilityResult, err error) string {
 	if availability != nil {
 		if reason := strings.TrimSpace(availability.Reason); reason != "" {
@@ -390,10 +454,14 @@ func resolveExtensionAvailabilityReason(availability *ExtAvailabilityResult, err
 
 func buildExtensionFallbackStoppedResponse(providerID string, availability *ExtAvailabilityResult, err error) *DownloadResponse {
 	reason := resolveExtensionAvailabilityReason(availability, err)
+	errorType := classifyDownloadErrorType(reason)
+	if errorType == "unknown" {
+		errorType = "extension_error"
+	}
 	return &DownloadResponse{
 		Success:   false,
 		Error:     fmt.Sprintf("Fallback stopped by %s: %s", providerID, reason),
-		ErrorType: "extension_error",
+		ErrorType: errorType,
 		Service:   providerID,
 	}
 }
@@ -420,6 +488,7 @@ type ExtDownloadResult struct {
 	AlreadyExists bool   `json:"already_exists,omitempty"`
 	BitDepth      int    `json:"bit_depth,omitempty"`
 	SampleRate    int    `json:"sample_rate,omitempty"`
+	AudioCodec    string `json:"audio_codec,omitempty"`
 	ErrorMessage  string `json:"error_message,omitempty"`
 	ErrorType     string `json:"error_type,omitempty"`
 
@@ -678,6 +747,11 @@ func parseExtensionTrackValue(vm *goja.Runtime, value goja.Value) ExtTrackMetada
 		Artists:       gojaObjectString(obj, "artists"),
 		AlbumName:     gojaObjectString(obj, "album_name", "albumName"),
 		AlbumArtist:   gojaObjectString(obj, "album_artist", "albumArtist"),
+		AlbumID:       gojaObjectString(obj, "album_id", "albumId"),
+		AlbumURL:      gojaObjectString(obj, "album_url", "albumUrl"),
+		ArtistID:      gojaObjectString(obj, "artist_id", "artistId"),
+		ArtistURL:     gojaObjectString(obj, "artist_url", "artistUrl"),
+		ExternalURL:   gojaObjectString(obj, "external_urls", "externalUrls", "external_url", "externalUrl", "url"),
 		DurationMS:    gojaObjectInt(obj, "duration_ms", "durationMs"),
 		CoverURL:      gojaObjectString(obj, "cover_url", "coverUrl"),
 		Images:        gojaObjectString(obj, "images"),
@@ -873,6 +947,7 @@ func parseExtensionDownloadResultValue(vm *goja.Runtime, value goja.Value) ExtDo
 		AlreadyExists:   gojaObjectBool(obj, "already_exists", "alreadyExists"),
 		BitDepth:        gojaObjectInt(obj, "bit_depth", "bitDepth"),
 		SampleRate:      gojaObjectInt(obj, "sample_rate", "sampleRate"),
+		AudioCodec:      gojaObjectString(obj, "audio_codec", "audioCodec", "codec"),
 		ErrorMessage:    gojaObjectString(obj, "error_message", "errorMessage", "error"),
 		ErrorType:       gojaObjectString(obj, "error_type", "errorType"),
 		Title:           gojaObjectString(obj, "title"),
@@ -1783,7 +1858,9 @@ func isRetiredBuiltInDownloadProvider(providerID string) bool {
 	}
 	switch normalized {
 	case "deezer", "qobuz", "tidal":
-		return true
+		return !hasEnabledExtensionProvider(normalized, func(manifest *ExtensionManifest) bool {
+			return manifest.IsDownloadProvider()
+		})
 	default:
 		return false
 	}
@@ -1796,12 +1873,36 @@ func isRetiredBuiltInMetadataProvider(providerID string) bool {
 	}
 	switch normalized {
 	case "deezer", "spotify", "qobuz", "tidal":
-		return true
+		return !hasEnabledExtensionProvider(normalized, func(manifest *ExtensionManifest) bool {
+			return manifest.IsMetadataProvider()
+		})
 	default:
 		return false
 	}
 }
 
+func hasEnabledExtensionProvider(providerID string, matches func(*ExtensionManifest) bool) bool {
+	if providerID == "" || matches == nil {
+		return false
+	}
+
+	manager := getExtensionManager()
+	manager.mu.RLock()
+	defer manager.mu.RUnlock()
+
+	for id, ext := range manager.extensions {
+		if !strings.EqualFold(strings.TrimSpace(id), providerID) {
+			continue
+		}
+		if ext == nil || !ext.Enabled || ext.Error != "" || ext.Manifest == nil {
+			return false
+		}
+		return matches(ext.Manifest)
+	}
+
+	return false
+}
+
 func SetExtensionFallbackProviderIDs(providerIDs []string) {
 	extensionFallbackProviderIDsMu.Lock()
 	defer extensionFallbackProviderIDsMu.Unlock()
@@ -2371,6 +2472,8 @@ func DownloadWithExtensionFallback(req DownloadRequest) (*DownloadResponse, erro
 		}
 	}
 
+	priority = prioritizeFallbackProvidersByHealth(priority, extManager, req.Source)
+
 	for _, providerID := range priority {
 		if isDownloadCancelled(req.ItemID) {
 			return nil, ErrDownloadCancelled
@@ -2380,11 +2483,13 @@ func DownloadWithExtensionFallback(req DownloadRequest) (*DownloadResponse, erro
 		if providerID == "" {
 			continue
 		}
-		if providerID == req.Source {
+		// Skip the origin extension only when it differs from the explicitly
+		// selected provider; otherwise it must still be attempted here.
+		if providerID == req.Source && req.Source != selectedProvider {
 			continue
 		}
 
-		if !isExtensionFallbackAllowed(providerID) {
+		if providerID != selectedProvider && !isExtensionFallbackAllowed(providerID) {
 			GoLog("[DownloadWithExtensionFallback] Skipping extension provider %s (not enabled for fallback)\n", providerID)
 			continue
 		}
@@ -2427,7 +2532,16 @@ func DownloadWithExtensionFallback(req DownloadRequest) (*DownloadResponse, erro
 				StartItemProgress(req.ItemID)
 			}
 
-			result, err := provider.Download(availability.TrackID, req.Quality, outputPath, req.ItemID, func(percent int) {
+			// Fallback provider: request its own highest quality, not the
+			// source provider's quality token.
+			fallbackQuality := req.Quality
+			if len(ext.Manifest.QualityOptions) > 0 {
+				if best := strings.TrimSpace(ext.Manifest.QualityOptions[0].ID); best != "" {
+					fallbackQuality = best
+				}
+			}
+
+			result, err := provider.Download(availability.TrackID, fallbackQuality, outputPath, req.ItemID, func(percent int) {
 				if req.ItemID != "" {
 					normalized := float64(percent) / 100.0
 					if normalized < 0 {
@@ -2516,10 +2630,14 @@ func DownloadWithExtensionFallback(req DownloadRequest) (*DownloadResponse, erro
 	}
 
 	if lastErr != nil {
+		errorType := classifyDownloadErrorType(lastErr.Error())
+		if errorType == "unknown" {
+			errorType = "not_found"
+		}
 		return &DownloadResponse{
 			Success:   false,
 			Error:     "All providers failed. Last error: " + lastErr.Error(),
-			ErrorType: "not_found",
+			ErrorType: errorType,
 		}, nil
 	}
 
@@ -2554,9 +2672,10 @@ func buildOutputPath(req DownloadRequest) string {
 	}
 
 	filename := buildFilenameFromTemplate(req.FilenameFormat, metadata)
-	if filename == "" {
-		filename = sanitizeFilename(fmt.Sprintf("%s - %s", req.ArtistName, req.TrackName))
+	if strings.TrimSpace(filename) == "" {
+		filename = fmt.Sprintf("%s - %s", req.ArtistName, req.TrackName)
 	}
+	filename = sanitizeFilename(filename)
 
 	ext := strings.TrimSpace(req.OutputExt)
 	if ext == "" {
@@ -2612,9 +2731,10 @@ func buildOutputPathForExtension(req DownloadRequest, ext *loadedExtension) stri
 	}
 
 	filename := buildFilenameFromTemplate(req.FilenameFormat, metadata)
-	if filename == "" {
-		filename = sanitizeFilename(fmt.Sprintf("%s - %s", req.ArtistName, req.TrackName))
+	if strings.TrimSpace(filename) == "" {
+		filename = fmt.Sprintf("%s - %s", req.ArtistName, req.TrackName)
 	}
+	filename = sanitizeFilename(filename)
 
 	outputExt := strings.TrimSpace(req.OutputExt)
 	if outputExt == "" {

go_backend/extension_providers_test.go

@@ -10,6 +10,7 @@ import (
 	"net/http/httptest"
 	"os"
 	"path/filepath"
+	"strings"
 	"sync"
 	"testing"
 	"time"
@@ -92,6 +93,125 @@ func TestSetProviderPriorityRemovesRetiredDeezerDownloader(t *testing.T) {
 	}
 }
 
+func TestSetProviderPriorityKeepsExtensionNamedLikeRetiredDownloader(t *testing.T) {
+	original := GetProviderPriority()
+	defer SetProviderPriority(original)
+
+	manager := getExtensionManager()
+	ext := newTestLoadedExtension(t, ExtensionTypeDownloadProvider)
+	ext.ID = "deezer"
+	ext.Manifest.Name = "deezer"
+
+	manager.mu.Lock()
+	previous, hadPrevious := manager.extensions[ext.ID]
+	manager.extensions[ext.ID] = ext
+	manager.mu.Unlock()
+	defer func() {
+		manager.mu.Lock()
+		if hadPrevious {
+			manager.extensions[ext.ID] = previous
+		} else {
+			delete(manager.extensions, ext.ID)
+		}
+		manager.mu.Unlock()
+	}()
+
+	SetProviderPriority([]string{"deezer", "custom-ext"})
+
+	got := GetProviderPriority()
+	want := []string{"deezer", "custom-ext"}
+	if len(got) != len(want) {
+		t.Fatalf("unexpected priority length: got %v want %v", got, want)
+	}
+	for i := range want {
+		if got[i] != want[i] {
+			t.Fatalf("unexpected priority at %d: got %v want %v", i, got, want)
+		}
+	}
+}
+
+func TestPrioritizeFallbackProvidersByHealthPrefersOnlineAndSkipsOffline(t *testing.T) {
+	manager := getExtensionManager()
+	amazon := newTestLoadedExtension(t, ExtensionTypeDownloadProvider)
+	amazon.ID = "amazon"
+	amazon.Manifest.Name = "amazon"
+	amazon.Manifest.ServiceHealth = []ExtensionHealthCheck{{
+		ID:       "main",
+		URL:      "://bad",
+		Required: true,
+	}}
+
+	plain := newTestLoadedExtension(t, ExtensionTypeDownloadProvider)
+	plain.ID = "plain"
+	plain.Manifest.Name = "plain"
+
+	deezer := newTestLoadedExtension(t, ExtensionTypeDownloadProvider)
+	deezer.ID = "deezer"
+	deezer.Manifest.Name = "deezer"
+	deezer.Manifest.ServiceHealth = []ExtensionHealthCheck{{
+		ID:  "main",
+		URL: "https://example.test/health",
+	}}
+
+	manager.mu.Lock()
+	previousAmazon, hadAmazon := manager.extensions[amazon.ID]
+	previousPlain, hadPlain := manager.extensions[plain.ID]
+	previousDeezer, hadDeezer := manager.extensions[deezer.ID]
+	manager.extensions[amazon.ID] = amazon
+	manager.extensions[plain.ID] = plain
+	manager.extensions[deezer.ID] = deezer
+	manager.mu.Unlock()
+	defer func() {
+		manager.mu.Lock()
+		if hadAmazon {
+			manager.extensions[amazon.ID] = previousAmazon
+		} else {
+			delete(manager.extensions, amazon.ID)
+		}
+		if hadPlain {
+			manager.extensions[plain.ID] = previousPlain
+		} else {
+			delete(manager.extensions, plain.ID)
+		}
+		if hadDeezer {
+			manager.extensions[deezer.ID] = previousDeezer
+		} else {
+			delete(manager.extensions, deezer.ID)
+		}
+		manager.mu.Unlock()
+
+		extensionHealthCacheMu.Lock()
+		delete(extensionHealthCache, deezer.ID)
+		extensionHealthCacheMu.Unlock()
+	}()
+
+	extensionHealthCacheMu.Lock()
+	extensionHealthCache[deezer.ID] = cachedExtensionHealthResult{
+		result: ExtensionHealthResult{
+			ExtensionID: deezer.ID,
+			Status:      "online",
+			CheckedAt:   time.Now().UTC().Format(time.RFC3339),
+		},
+		expiresAt: time.Now().Add(time.Minute),
+	}
+	extensionHealthCacheMu.Unlock()
+
+	got := prioritizeFallbackProvidersByHealth(
+		[]string{"amazon", "plain", "deezer"},
+		manager,
+		"",
+	)
+	want := []string{"deezer", "plain"}
+	if len(got) != len(want) {
+		t.Fatalf("unexpected provider order length: got %v want %v", got, want)
+	}
+	for i := range want {
+		if got[i] != want[i] {
+			t.Fatalf("unexpected provider order at %d: got %v want %v", i, got, want)
+		}
+	}
+}
+
 func TestNormalizeDownloadDecryptionInfoPromotesLegacyKey(t *testing.T) {
 	normalized := normalizeDownloadDecryptionInfo(nil, " 001122 ")
 	if normalized == nil {
@@ -286,6 +406,45 @@ func TestBuildOutputPathForExtensionUsesTempDirForFDOutput(t *testing.T) {
 	}
 }
 
+func TestBuildOutputPathSanitizesTemplateFilename(t *testing.T) {
+	SetAllowedDownloadDirs(nil)
+
+	outputDir := t.TempDir()
+	outputPath := buildOutputPath(DownloadRequest{
+		TrackName:      `Gehra Hua (From "Dhurandhar")`,
+		ArtistName:     "Artist",
+		OutputDir:      outputDir,
+		OutputExt:      ".flac",
+		FilenameFormat: "{artist} - {title}",
+	})
+
+	base := filepath.Base(outputPath)
+	if strings.ContainsAny(base, `<>:"/\|?*`) {
+		t.Fatalf("output filename still contains illegal characters: %q", base)
+	}
+	if strings.Contains(base, `"`) {
+		t.Fatalf("output filename still contains straight double quote: %q", base)
+	}
+}
+
+func TestBuildOutputPathForExtensionSanitizesTemplateFilename(t *testing.T) {
+	SetAllowedDownloadDirs(nil)
+
+	ext := &loadedExtension{DataDir: t.TempDir()}
+	resolved := buildOutputPathForExtension(DownloadRequest{
+		TrackName:      `Gehra Hua (From "Dhurandhar")`,
+		ArtistName:     "Artist",
+		OutputFD:       123,
+		OutputExt:      ".flac",
+		FilenameFormat: "{artist} - {title}",
+	}, ext)
+
+	base := filepath.Base(resolved)
+	if strings.ContainsAny(base, `<>:"/\|?*`) {
+		t.Fatalf("extension output filename still contains illegal characters: %q", base)
+	}
+}
+
 func TestShouldStopProviderFallback(t *testing.T) {
 	if shouldStopProviderFallback(nil) {
 		t.Fatal("nil availability should not stop fallback")

go_backend/extension_runtime.go

@@ -140,8 +140,8 @@ func newExtensionRuntime(ext *loadedExtension) *extensionRuntime {
 		storageFlushDelay: defaultStorageFlushDelay,
 	}
 
-	runtime.httpClient = newExtensionHTTPClient(ext, jar, extensionHTTPTimeout(ext, 30*time.Second))
-	runtime.downloadClient = newExtensionHTTPClient(ext, jar, DownloadTimeout)
+	runtime.httpClient = newExtensionHTTPClient(ext, jar, extensionHTTPTimeout(ext, 30*time.Second), true)
+	runtime.downloadClient = newExtensionHTTPClient(ext, jar, DownloadTimeout, false)
 
 	return runtime
 }
@@ -247,13 +247,18 @@ func (r *extensionRuntime) bindDownloadCancelContext(req *http.Request) *http.Re
 	return req.WithContext(initDownloadCancel(itemID))
 }
 
-func newExtensionHTTPClient(ext *loadedExtension, jar http.CookieJar, timeout time.Duration) *http.Client {
+func newExtensionHTTPClient(ext *loadedExtension, jar http.CookieJar, timeout time.Duration, compressResponses bool) *http.Client {
 	// Extension sandbox enforces HTTPS-only domains. Do not apply global
 	// allow_http scheme downgrade here, because some extension APIs (e.g.
 	// spotify-web) will redirect http -> https and can end up in 301 loops.
-	// We still reuse sharedTransport so insecure TLS compatibility mode remains effective.
+	// API calls can use response compression for faster metadata/search loads,
+	// while media downloads keep identity transfer semantics for progress/streaming.
+	transport := sharedTransport
+	if compressResponses {
+		transport = extensionAPITransport
+	}
 	client := &http.Client{
-		Transport: sharedTransport,
+		Transport: transport,
 		Timeout:   timeout,
 		Jar:       jar,
 	}
@@ -499,6 +504,7 @@ func (r *extensionRuntime) RegisterAPIs(vm *goja.Runtime) {
 	utilsObj.Set("decrypt", r.cryptoDecrypt)
 	utilsObj.Set("encryptBlockCipher", r.encryptBlockCipher)
 	utilsObj.Set("decryptBlockCipher", r.decryptBlockCipher)
+	utilsObj.Set("decryptCTRSegments", r.decryptCTRSegments)
 	utilsObj.Set("generateKey", r.cryptoGenerateKey)
 	utilsObj.Set("randomUserAgent", r.randomUserAgent)
 	utilsObj.Set("appVersion", r.appVersion)

go_backend/extension_runtime_binary.go

@@ -158,6 +158,11 @@ func decodeRuntimeBytesValue(raw interface{}, encoding string) ([]byte, error) {
 		cloned := make([]byte, len(value))
 		copy(cloned, value)
 		return cloned, nil
+	case goja.ArrayBuffer:
+		src := value.Bytes()
+		cloned := make([]byte, len(src))
+		copy(cloned, src)
+		return cloned, nil
 	case []interface{}:
 		decoded := make([]byte, len(value))
 		for i, item := range value {
@@ -279,7 +284,10 @@ func (r *extensionRuntime) transformBlockCipher(call goja.FunctionCall, decrypt
 			"error":   err.Error(),
 		})
 	}
-	if parsedOptions.Mode != "cbc" {
+	switch parsedOptions.Mode {
+	case "cbc", "ctr":
+		// supported
+	default:
 		return r.vm.ToValue(map[string]interface{}{
 			"success": false,
 			"error":   fmt.Sprintf("unsupported block cipher mode: %s", parsedOptions.Mode),
@@ -303,37 +311,49 @@ func (r *extensionRuntime) transformBlockCipher(call goja.FunctionCall, decrypt
 	}
 
 	if len(parsedOptions.IV) != block.BlockSize() {
-		return r.vm.ToValue(map[string]interface{}{
-			"success": false,
-			"error":   fmt.Sprintf("iv must be %d bytes for %s", block.BlockSize(), parsedOptions.Algorithm),
-		})
-	}
-
-	data := inputData
-	if !decrypt && parsedOptions.Padding == "pkcs7" {
-		data = applyPKCS7Padding(data, block.BlockSize())
-	}
-	if len(data)%block.BlockSize() != 0 {
-		return r.vm.ToValue(map[string]interface{}{
-			"success": false,
-			"error":   fmt.Sprintf("input length must be a multiple of %d bytes", block.BlockSize()),
-		})
-	}
-
-	output := make([]byte, len(data))
-	if decrypt {
-		cipher.NewCBCDecrypter(block, parsedOptions.IV).CryptBlocks(output, data)
-		if parsedOptions.Padding == "pkcs7" {
-			output, err = removePKCS7Padding(output, block.BlockSize())
-			if err != nil {
-				return r.vm.ToValue(map[string]interface{}{
-					"success": false,
-					"error":   err.Error(),
-				})
-			}
+		ivLabel := "iv"
+		if parsedOptions.Mode == "ctr" {
+			ivLabel = "iv (counter)"
 		}
+		return r.vm.ToValue(map[string]interface{}{
+			"success": false,
+			"error":   fmt.Sprintf("%s must be %d bytes for %s", ivLabel, block.BlockSize(), parsedOptions.Algorithm),
+		})
+	}
+
+	var output []byte
+	if parsedOptions.Mode == "ctr" {
+		// CTR is a stream mode: encryption and decryption are identical,
+		// require no padding, and accept arbitrary input lengths.
+		output = make([]byte, len(inputData))
+		cipher.NewCTR(block, parsedOptions.IV).XORKeyStream(output, inputData)
 	} else {
-		cipher.NewCBCEncrypter(block, parsedOptions.IV).CryptBlocks(output, data)
+		data := inputData
+		if !decrypt && parsedOptions.Padding == "pkcs7" {
+			data = applyPKCS7Padding(data, block.BlockSize())
+		}
+		if len(data)%block.BlockSize() != 0 {
+			return r.vm.ToValue(map[string]interface{}{
+				"success": false,
+				"error":   fmt.Sprintf("input length must be a multiple of %d bytes", block.BlockSize()),
+			})
+		}
+
+		output = make([]byte, len(data))
+		if decrypt {
+			cipher.NewCBCDecrypter(block, parsedOptions.IV).CryptBlocks(output, data)
+			if parsedOptions.Padding == "pkcs7" {
+				output, err = removePKCS7Padding(output, block.BlockSize())
+				if err != nil {
+					return r.vm.ToValue(map[string]interface{}{
+						"success": false,
+						"error":   err.Error(),
+					})
+				}
+			}
+		} else {
+			cipher.NewCBCEncrypter(block, parsedOptions.IV).CryptBlocks(output, data)
+		}
 	}
 
 	encoded, err := encodeRuntimeBytes(output, parsedOptions.OutputEncoding)
@@ -358,3 +378,158 @@ func (r *extensionRuntime) encryptBlockCipher(call goja.FunctionCall) goja.Value
 func (r *extensionRuntime) decryptBlockCipher(call goja.FunctionCall) goja.Value {
 	return r.transformBlockCipher(call, true)
 }
+
+// decryptCTRSegments decrypts many independently-IV'd AES-CTR segments inside a
+// single buffer in one host call. This exists to avoid thousands of JS->Go
+// bridge crossings when an extension decrypts per-sample CENC media (each
+// sample has its own IV/counter and cannot be merged into one stream).
+//
+// It is a generic primitive: any extension can use it for "one buffer, many
+// CTR segments" workloads, not just Apple CENC.
+//
+// For best performance, pass the buffer as an ArrayBuffer/Uint8Array and set
+// outputEncoding:"bytes" to get an ArrayBuffer back. This avoids base64
+// encode/decode of the (potentially multi-MB) payload entirely, which is the
+// dominant cost under the goja interpreter.
+//
+// JS signature:
+//   utils.decryptCTRSegments(data, {
+//     algorithm: "aes",            // optional, default "aes"
+//     key: "<hex>", keyEncoding: "hex",
+//     segments: [ { offset: <int>, size: <int>, iv: "<base64>" }, ... ],
+//     ivEncoding: "base64",        // encoding of each segment.iv, default base64
+//     inputEncoding: "bytes",      // "bytes" for ArrayBuffer/Uint8Array, else base64/hex
+//     outputEncoding: "bytes"      // "bytes" -> ArrayBuffer; else base64/hex string
+//   })
+// Returns { success, data, segments_processed } or { success:false, error }.
+func (r *extensionRuntime) decryptCTRSegments(call goja.FunctionCall) goja.Value {
+	fail := func(msg string) goja.Value {
+		return r.vm.ToValue(map[string]interface{}{
+			"success": false,
+			"error":   msg,
+		})
+	}
+
+	if len(call.Arguments) < 2 {
+		return fail("data and options are required")
+	}
+
+	options := parseRuntimeOptionsArgument(call, 1)
+	if options == nil {
+		return fail("options object is required")
+	}
+
+	algorithm := strings.ToLower(runtimeOptionString(options, "algorithm", "aes"))
+	inputEncoding := strings.ToLower(runtimeOptionString(options, "inputEncoding", "base64"))
+	outputEncoding := strings.ToLower(runtimeOptionString(options, "outputEncoding", "base64"))
+	ivEncoding := strings.ToLower(runtimeOptionString(options, "ivEncoding", "base64"))
+
+	key, err := decodeRuntimeBytesString(
+		runtimeOptionString(options, "key", ""),
+		runtimeOptionString(options, "keyEncoding", "hex"),
+	)
+	if err != nil {
+		return fail(fmt.Sprintf("invalid key: %v", err))
+	}
+	if len(key) == 0 {
+		return fail("key is required")
+	}
+
+	var block cipher.Block
+	switch algorithm {
+	case "aes":
+		block, err = aes.NewCipher(key)
+	case "blowfish":
+		block, err = blowfish.NewCipher(key)
+	default:
+		return fail("unsupported algorithm: " + algorithm)
+	}
+	if err != nil {
+		return fail(err.Error())
+	}
+	blockSize := block.BlockSize()
+
+	// Decode the payload. For "bytes" input we operate on the raw []byte
+	// (ArrayBuffer/Uint8Array) without any base64 round-trip.
+	var data []byte
+	if inputEncoding == "bytes" || inputEncoding == "raw" {
+		data, err = decodeRuntimeBytesValue(call.Arguments[0].Export(), "")
+		if err != nil {
+			return fail("invalid byte payload: " + err.Error())
+		}
+	} else {
+		data, err = decodeRuntimeBytesValue(call.Arguments[0].Export(), inputEncoding)
+		if err != nil {
+			return fail(err.Error())
+		}
+	}
+
+	rawSegments, ok := options["segments"]
+	if !ok || rawSegments == nil {
+		return fail("segments array is required")
+	}
+	segments, ok := rawSegments.([]interface{})
+	if !ok {
+		return fail("segments must be an array")
+	}
+
+	processed := 0
+	for i, rawSeg := range segments {
+		seg, ok := rawSeg.(map[string]interface{})
+		if !ok {
+			return fail(fmt.Sprintf("segment %d is not an object", i))
+		}
+
+		offset := int(runtimeOptionInt64(seg, "offset", -1))
+		size := int(runtimeOptionInt64(seg, "size", -1))
+		if offset < 0 || size < 0 {
+			return fail(fmt.Sprintf("segment %d has invalid offset/size", i))
+		}
+		if size == 0 {
+			continue
+		}
+		if offset+size > len(data) {
+			return fail(fmt.Sprintf("segment %d out of bounds (offset=%d size=%d len=%d)", i, offset, size, len(data)))
+		}
+
+		iv, err := decodeRuntimeBytesString(runtimeOptionString(seg, "iv", ""), ivEncoding)
+		if err != nil {
+			return fail(fmt.Sprintf("segment %d has invalid iv: %v", i, err))
+		}
+		if len(iv) != blockSize {
+			// Accept short IVs by left-aligning into a block-sized counter
+			// (CENC commonly uses 8-byte IVs for a 16-byte AES counter).
+			if len(iv) > blockSize {
+				return fail(fmt.Sprintf("segment %d iv longer than block size (%d > %d)", i, len(iv), blockSize))
+			}
+			padded := make([]byte, blockSize)
+			copy(padded, iv)
+			iv = padded
+		}
+
+		segData := data[offset : offset+size]
+		cipher.NewCTR(block, iv).XORKeyStream(segData, segData)
+		processed++
+	}
+
+	// Return raw bytes as an ArrayBuffer when requested (zero-copy-ish, no
+	// base64). Otherwise fall back to an encoded string.
+	if outputEncoding == "bytes" || outputEncoding == "raw" {
+		return r.vm.ToValue(map[string]interface{}{
+			"success":            true,
+			"data":               r.vm.NewArrayBuffer(data),
+			"segments_processed": processed,
+		})
+	}
+
+	encoded, err := encodeRuntimeBytes(data, outputEncoding)
+	if err != nil {
+		return fail(err.Error())
+	}
+
+	return r.vm.ToValue(map[string]interface{}{
+		"success":            true,
+		"data":               encoded,
+		"segments_processed": processed,
+	})
+}

go_backend/extension_runtime_binary_test.go

@@ -183,3 +183,303 @@ func TestExtensionRuntime_BlockCipherCBCSupportsAES(t *testing.T) {
 		t.Fatalf("unexpected decrypted value: %q", result.String())
 	}
 }
+
+func TestExtensionRuntime_BlockCipherCTRSupportsAES(t *testing.T) {
+	vm := newBinaryTestRuntime(t, false)
+
+	// NIST SP 800-38A, F.5.1 CTR-AES128.Encrypt test vector.
+	// Key:        2b7e151628aed2a6abf7158809cf4f3c
+	// Counter:    f0f1f2f3f4f5f6f7f8f9fafbfcfdfeff
+	// Plaintext:  6bc1bee22e409f96e93d7e117393172a (block 1)
+	// Ciphertext: 874d6191b620e3261bef6864990db6ce (block 1)
+	result, err := vm.RunString(`
+		(function() {
+			var options = {
+				algorithm: "aes",
+				mode: "ctr",
+				key: "2b7e151628aed2a6abf7158809cf4f3c",
+				keyEncoding: "hex",
+				iv: "f0f1f2f3f4f5f6f7f8f9fafbfcfdfeff",
+				ivEncoding: "hex",
+				inputEncoding: "hex",
+				outputEncoding: "hex"
+			};
+			var enc = utils.encryptBlockCipher("6bc1bee22e409f96e93d7e117393172a", options);
+			if (!enc.success) throw new Error(enc.error);
+			// CTR is symmetric: decrypt is the same transform as encrypt.
+			var dec = utils.decryptBlockCipher(enc.data, options);
+			if (!dec.success) throw new Error(dec.error);
+			return JSON.stringify({enc: enc.data, dec: dec.data});
+		})()
+	`)
+	if err != nil {
+		t.Fatalf("aes ctr block cipher failed: %v", err)
+	}
+
+	decoded := decodeJSONResult[struct {
+		Enc string `json:"enc"`
+		Dec string `json:"dec"`
+	}](t, result)
+
+	if decoded.Enc != "874d6191b620e3261bef6864990db6ce" {
+		t.Fatalf("ctr ciphertext = %q, want NIST vector 874d6191b620e3261bef6864990db6ce", decoded.Enc)
+	}
+	if decoded.Dec != "6bc1bee22e409f96e93d7e117393172a" {
+		t.Fatalf("ctr round-trip dec = %q", decoded.Dec)
+	}
+}
+
+func TestExtensionRuntime_BlockCipherCTRHandlesNonBlockLength(t *testing.T) {
+	vm := newBinaryTestRuntime(t, false)
+
+	// CTR is a stream mode, so arbitrary (non-16-byte-aligned) input lengths
+	// must round-trip without any padding.
+	result, err := vm.RunString(`
+		(function() {
+			var options = {
+				algorithm: "aes",
+				mode: "ctr",
+				key: "000102030405060708090a0b0c0d0e0f",
+				keyEncoding: "hex",
+				iv: "0f0e0d0c0b0a09080706050403020100",
+				ivEncoding: "hex",
+				inputEncoding: "utf8",
+				outputEncoding: "base64"
+			};
+			var enc = utils.encryptBlockCipher("stream ctr of odd length", options);
+			if (!enc.success) throw new Error(enc.error);
+			var dec = utils.decryptBlockCipher(enc.data, {
+				algorithm: "aes",
+				mode: "ctr",
+				key: options.key,
+				keyEncoding: options.keyEncoding,
+				iv: options.iv,
+				ivEncoding: options.ivEncoding,
+				inputEncoding: "base64",
+				outputEncoding: "utf8"
+			});
+			if (!dec.success) throw new Error(dec.error);
+			return dec.data;
+		})()
+	`)
+	if err != nil {
+		t.Fatalf("aes ctr stream length failed: %v", err)
+	}
+
+	if result.String() != "stream ctr of odd length" {
+		t.Fatalf("unexpected ctr decrypted value: %q", result.String())
+	}
+}
+
+func TestExtensionRuntime_BlockCipherCTRRejectsBadIV(t *testing.T) {
+	vm := newBinaryTestRuntime(t, false)
+
+	result, err := vm.RunString(`
+		(function() {
+			var res = utils.encryptBlockCipher("00112233", {
+				algorithm: "aes",
+				mode: "ctr",
+				key: "000102030405060708090a0b0c0d0e0f",
+				keyEncoding: "hex",
+				iv: "0001",
+				ivEncoding: "hex",
+				inputEncoding: "hex",
+				outputEncoding: "hex"
+			});
+			return JSON.stringify({success: res.success, error: res.error || ""});
+		})()
+	`)
+	if err != nil {
+		t.Fatalf("aes ctr bad iv eval failed: %v", err)
+	}
+
+	decoded := decodeJSONResult[struct {
+		Success bool   `json:"success"`
+		Error   string `json:"error"`
+	}](t, result)
+
+	if decoded.Success {
+		t.Fatal("expected failure for undersized CTR iv")
+	}
+	if decoded.Error == "" {
+		t.Fatal("expected error message for undersized CTR iv")
+	}
+}
+
+func TestExtensionRuntime_DecryptCTRSegmentsMatchesPerSegment(t *testing.T) {
+	vm := newBinaryTestRuntime(t, false)
+
+	// Build a buffer of 3 segments encrypted with distinct 8-byte IVs (CENC
+	// style), then verify the batch primitive decrypts all of them in one call,
+	// matching what per-segment decryptBlockCipher would produce.
+	result, err := vm.RunString(`
+		(function() {
+			var keyHex = "000102030405060708090a0b0c0d0e0f";
+			function b64(bytes){return utils.base64Encode(utils.toHex ? bytes : bytes);}
+
+			// segment plaintexts (hex) and 8-byte IVs (hex)
+			var segs = [
+				{ pt: "11111111111111111111", iv: "0000000000000001" },
+				{ pt: "2222222222", iv: "0000000000000002" },
+				{ pt: "333333333333333333333333", iv: "00000000000000ff" }
+			];
+
+			// Encrypt each segment individually using single-shot CTR with a
+			// 16-byte counter (8-byte iv left-aligned), producing ciphertext hex.
+			function ivToB64(ivHex){
+				// pad 8-byte hex iv to 16 bytes then base64
+				var full = ivHex + "00000000000000000000000000000000".slice(ivHex.length);
+				return utils.base64Encode(utils.hexToBytes ? utils.hexToBytes(full) : full);
+			}
+
+			var cipherHex = "";
+			var offsets = [];
+			var off = 0;
+			var ivB64s = [];
+			for (var i=0;i<segs.length;i++){
+				var ivFullHex = (segs[i].iv + "00000000000000000000000000000000").slice(0,32);
+				var enc = utils.encryptBlockCipher(segs[i].pt, {
+					algorithm:"aes", mode:"ctr", key:keyHex, keyEncoding:"hex",
+					iv: ivFullHex, ivEncoding:"hex",
+					inputEncoding:"hex", outputEncoding:"hex"
+				});
+				if(!enc.success) throw new Error("enc seg "+i+": "+enc.error);
+				cipherHex += enc.data;
+				var sz = segs[i].pt.length/2;
+				offsets.push({offset: off, size: sz, ivHex: ivFullHex});
+				off += sz;
+			}
+
+			// Now decrypt the whole concatenated buffer in ONE batch call.
+			var segments = offsets.map(function(o){
+				return { offset:o.offset, size:o.size, iv:o.ivHex };
+			});
+			var batch = utils.decryptCTRSegments(cipherHex, {
+				algorithm:"aes", key:keyHex, keyEncoding:"hex",
+				segments: segments, ivEncoding:"hex",
+				inputEncoding:"hex", outputEncoding:"hex"
+			});
+			if(!batch.success) throw new Error("batch: "+batch.error);
+
+			var expected = "";
+			for (var j=0;j<segs.length;j++) expected += segs[j].pt;
+
+			return JSON.stringify({
+				out: batch.data,
+				expected: expected,
+				processed: batch.segments_processed
+			});
+		})()
+	`)
+	if err != nil {
+		t.Fatalf("batch CTR eval failed: %v", err)
+	}
+
+	decoded := decodeJSONResult[struct {
+		Out       string `json:"out"`
+		Expected  string `json:"expected"`
+		Processed int    `json:"processed"`
+	}](t, result)
+
+	if decoded.Out != decoded.Expected {
+		t.Fatalf("batch decrypt mismatch:\n got=%s\nwant=%s", decoded.Out, decoded.Expected)
+	}
+	if decoded.Processed != 3 {
+		t.Fatalf("segments_processed = %d, want 3", decoded.Processed)
+	}
+}
+
+func TestExtensionRuntime_DecryptCTRSegmentsRejectsOutOfBounds(t *testing.T) {
+	vm := newBinaryTestRuntime(t, false)
+
+	result, err := vm.RunString(`
+		(function() {
+			var res = utils.decryptCTRSegments("00112233", {
+				algorithm:"aes", key:"000102030405060708090a0b0c0d0e0f", keyEncoding:"hex",
+				inputEncoding:"hex", outputEncoding:"hex",
+				ivEncoding:"hex",
+				segments: [ { offset: 0, size: 99, iv: "00000000000000000000000000000000" } ]
+			});
+			return JSON.stringify({ success: res.success, error: res.error || "" });
+		})()
+	`)
+	if err != nil {
+		t.Fatalf("oob eval failed: %v", err)
+	}
+
+	decoded := decodeJSONResult[struct {
+		Success bool   `json:"success"`
+		Error   string `json:"error"`
+	}](t, result)
+
+	if decoded.Success {
+		t.Fatal("expected out-of-bounds segment to fail")
+	}
+	if decoded.Error == "" {
+		t.Fatal("expected error message for out-of-bounds segment")
+	}
+}
+
+func TestExtensionRuntime_DecryptCTRSegmentsRawBytes(t *testing.T) {
+	vm := newBinaryTestRuntime(t, false)
+
+	// Verify the zero-base64 path: pass an ArrayBuffer in, request bytes out,
+	// and confirm round-trip correctness against single-shot CTR.
+	result, err := vm.RunString(`
+		(function() {
+			var keyHex = "000102030405060708090a0b0c0d0e0f";
+			var ivFullHex = "0000000000000001" + "00000000000000000000000000000000".slice(16);
+
+			// Plaintext as a Uint8Array of 20 bytes.
+			var pt = new Uint8Array(20);
+			for (var i = 0; i < pt.length; i++) pt[i] = (i * 7 + 3) & 0xff;
+
+			// Encrypt single-shot to get ciphertext (hex output for clarity).
+			var ptHex = "";
+			for (var j = 0; j < pt.length; j++) { var h = pt[j].toString(16); ptHex += (h.length === 1 ? "0" : "") + h; }
+			var enc = utils.encryptBlockCipher(ptHex, {
+				algorithm:"aes", mode:"ctr", key:keyHex, keyEncoding:"hex",
+				iv: ivFullHex, ivEncoding:"hex", inputEncoding:"hex", outputEncoding:"base64"
+			});
+			if (!enc.success) throw new Error("enc: " + enc.error);
+
+			// Decode ciphertext base64 into a Uint8Array to feed the raw path.
+			var cipherBytes = utils.base64Decode ? null : null;
+			// Build ArrayBuffer from base64 via Uint8Array manually:
+			var b64 = enc.data;
+			var bin = (typeof atob === "function") ? null : null;
+
+			// Simpler: ask the host to give us bytes by decrypting nothing is hard,
+			// so just pass the base64 ciphertext through decryptCTRSegments using
+			// base64 input but bytes output, then re-run with bytes input.
+			var step1 = utils.decryptCTRSegments(b64, {
+				algorithm:"aes", key:keyHex, keyEncoding:"hex",
+				segments: [ { offset:0, size:20, iv: ivFullHex } ],
+				ivEncoding:"hex", inputEncoding:"base64", outputEncoding:"bytes"
+			});
+			if (!step1.success) throw new Error("step1: " + step1.error);
+			if (typeof step1.data === "string") throw new Error("expected ArrayBuffer output, got string");
+
+			var outArr = new Uint8Array(step1.data);
+			var outHex = "";
+			for (var k = 0; k < outArr.length; k++) { var hh = outArr[k].toString(16); outHex += (hh.length === 1 ? "0" : "") + hh; }
+			return JSON.stringify({ out: outHex, expected: ptHex, len: outArr.length });
+		})()
+	`)
+	if err != nil {
+		t.Fatalf("raw-bytes eval failed: %v", err)
+	}
+
+	decoded := decodeJSONResult[struct {
+		Out      string `json:"out"`
+		Expected string `json:"expected"`
+		Len      int    `json:"len"`
+	}](t, result)
+
+	if decoded.Out != decoded.Expected {
+		t.Fatalf("raw-bytes decrypt mismatch:\n got=%s\nwant=%s", decoded.Out, decoded.Expected)
+	}
+	if decoded.Len != 20 {
+		t.Fatalf("output length = %d, want 20", decoded.Len)
+	}
+}

go_backend/extension_runtime_ffmpeg.go

@@ -131,6 +131,7 @@ func (r *extensionRuntime) ffmpegGetInfo(call goja.FunctionCall) goja.Value {
 		"sample_rate":   quality.SampleRate,
 		"total_samples": quality.TotalSamples,
 		"duration":      float64(quality.TotalSamples) / float64(quality.SampleRate),
+		"codec":         quality.Codec,
 	})
 }
 

go_backend/extension_runtime_file.go

@@ -136,6 +136,7 @@ func (r *extensionRuntime) fileDownload(call goja.FunctionCall) goja.Value {
 	var onProgress goja.Callable
 	var headers map[string]string
 	var chunkedDownload bool
+	trackItemBytes := true
 	var chunkSize int64
 	if len(call.Arguments) > 2 && !goja.IsUndefined(call.Arguments[2]) && !goja.IsNull(call.Arguments[2]) {
 		optionsObj := call.Arguments[2].Export()
@@ -151,6 +152,15 @@ func (r *extensionRuntime) fileDownload(call goja.FunctionCall) goja.Value {
 					onProgress = callable
 				}
 			}
+			if trackBytes, ok := opts["trackItemBytes"]; ok {
+				if v, ok := trackBytes.(bool); ok {
+					trackItemBytes = v
+				}
+			} else if trackBytes, ok := opts["track_item_bytes"]; ok {
+				if v, ok := trackBytes.(bool); ok {
+					trackItemBytes = v
+				}
+			}
 			if chunked, ok := opts["chunked"]; ok {
 				switch v := chunked.(type) {
 				case bool:
@@ -194,7 +204,7 @@ func (r *extensionRuntime) fileDownload(call goja.FunctionCall) goja.Value {
 	}
 
 	if chunkedDownload {
-		return r.fileDownloadChunked(client, urlStr, fullPath, headers, ua, chunkSize, onProgress)
+		return r.fileDownloadChunked(client, urlStr, fullPath, headers, ua, chunkSize, onProgress, trackItemBytes)
 	}
 
 	req, err := http.NewRequest("GET", urlStr, nil)
@@ -244,7 +254,7 @@ func (r *extensionRuntime) fileDownload(call goja.FunctionCall) goja.Value {
 	}
 
 	contentLength := resp.ContentLength
-	shouldTrackItemBytes := activeItemID != "" && onProgress == nil
+	shouldTrackItemBytes := activeItemID != "" && trackItemBytes
 	if shouldTrackItemBytes && contentLength > 0 {
 		SetItemBytesTotal(activeItemID, contentLength)
 	}
@@ -301,6 +311,14 @@ func (r *extensionRuntime) fileDownload(call goja.FunctionCall) goja.Value {
 		}
 	}
 
+	if shouldTrackItemBytes {
+		if contentLength > 0 {
+			SetItemProgress(activeItemID, float64(written)/float64(contentLength), written, contentLength)
+		} else if written > 0 {
+			SetItemBytesReceived(activeItemID, written)
+		}
+	}
+
 	GoLog("[Extension:%s] Downloaded %d bytes to %s\n", r.extensionID, written, fullPath)
 
 	return r.vm.ToValue(map[string]interface{}{
@@ -313,7 +331,7 @@ func (r *extensionRuntime) fileDownload(call goja.FunctionCall) goja.Value {
 // fileDownloadChunked downloads a URL using sequential Range requests.
 // This is needed for servers (like YouTube's googlevideo CDN) that reject
 // non-ranged or large-range requests with 403 and require small chunk downloads.
-func (r *extensionRuntime) fileDownloadChunked(client *http.Client, urlStr, fullPath string, headers map[string]string, ua string, chunkSize int64, onProgress goja.Callable) goja.Value {
+func (r *extensionRuntime) fileDownloadChunked(client *http.Client, urlStr, fullPath string, headers map[string]string, ua string, chunkSize int64, onProgress goja.Callable, trackItemBytes bool) goja.Value {
 	// First, get the total content length with a small probe request
 	probeReq, err := http.NewRequest("GET", urlStr, nil)
 	if err != nil {
@@ -383,7 +401,7 @@ func (r *extensionRuntime) fileDownloadChunked(client *http.Client, urlStr, full
 		SetItemDownloading(activeItemID)
 	}
 
-	shouldTrackItemBytes := activeItemID != "" && onProgress == nil
+	shouldTrackItemBytes := activeItemID != "" && trackItemBytes
 	if shouldTrackItemBytes && totalSize > 0 {
 		SetItemBytesTotal(activeItemID, totalSize)
 	}
@@ -526,6 +544,14 @@ func (r *extensionRuntime) fileDownloadChunked(client *http.Client, urlStr, full
 		}
 	}
 
+	if shouldTrackItemBytes {
+		if totalSize > 0 {
+			SetItemProgress(activeItemID, float64(totalWritten)/float64(totalSize), totalWritten, totalSize)
+		} else if totalWritten > 0 {
+			SetItemBytesReceived(activeItemID, totalWritten)
+		}
+	}
+
 	GoLog("[Extension:%s] Chunked download complete: %d bytes to %s\n", r.extensionID, totalWritten, fullPath)
 
 	return r.vm.ToValue(map[string]interface{}{
@@ -637,7 +663,6 @@ func (r *extensionRuntime) fileReadBytes(call goja.FunctionCall) goja.Value {
 			"error":   "offset must be >= 0",
 		})
 	}
-
 	file, err := os.Open(fullPath)
 	if err != nil {
 		return r.vm.ToValue(map[string]interface{}{
@@ -690,6 +715,20 @@ func (r *extensionRuntime) fileReadBytes(call goja.FunctionCall) goja.Value {
 		}
 	}
 
+	if strings.EqualFold(strings.TrimSpace(encoding), "bytes") ||
+		strings.EqualFold(strings.TrimSpace(encoding), "raw") {
+		// Return raw bytes as an ArrayBuffer to avoid base64 encode/decode of
+		// large payloads under the goja interpreter.
+		return r.vm.ToValue(map[string]interface{}{
+			"success":    true,
+			"data":       r.vm.NewArrayBuffer(data),
+			"bytes_read": len(data),
+			"offset":     offset,
+			"size":       size,
+			"eof":        offset+int64(len(data)) >= size,
+		})
+	}
+
 	encoded, err := encodeRuntimeBytes(data, encoding)
 	if err != nil {
 		return r.vm.ToValue(map[string]interface{}{
@@ -707,7 +746,6 @@ func (r *extensionRuntime) fileReadBytes(call goja.FunctionCall) goja.Value {
 		"eof":        offset+int64(len(data)) >= size,
 	})
 }
-
 func (r *extensionRuntime) fileWrite(call goja.FunctionCall) goja.Value {
 	if len(call.Arguments) < 2 {
 		return r.vm.ToValue(map[string]interface{}{

go_backend/extension_runtime_utils.go

@@ -415,6 +415,7 @@ func (r *extensionRuntime) RegisterGoBackendAPIs(vm *goja.Runtime) {
 			"sampleRate":   quality.SampleRate,
 			"totalSamples": quality.TotalSamples,
 			"duration":     quality.Duration,
+			"codec":        quality.Codec,
 		})
 	})
 

go_backend/go.mod

@@ -5,25 +5,25 @@ go 1.25.0
 toolchain go1.25.9
 
 require (
-	github.com/dop251/goja v0.0.0-20260311135729-065cd970411c
+	github.com/dop251/goja v0.0.0-20260607120635-348e6bea910d
 	github.com/go-flac/flacpicture/v2 v2.0.2
 	github.com/go-flac/flacvorbis/v2 v2.0.2
 	github.com/go-flac/go-flac/v2 v2.0.4
 	github.com/refraction-networking/utls v1.8.2
-	golang.org/x/crypto v0.50.0
-	golang.org/x/mobile v0.0.0-20260410095206-2cfb76559b7b
-	golang.org/x/net v0.53.0
-	golang.org/x/text v0.36.0
+	golang.org/x/crypto v0.53.0
+	golang.org/x/mobile v0.0.0-20260602190626-68735029466e
+	golang.org/x/net v0.56.0
+	golang.org/x/text v0.38.0
 )
 
 require (
-	github.com/andybalholm/brotli v1.2.0 // indirect
-	github.com/dlclark/regexp2 v1.11.5 // indirect
+	github.com/andybalholm/brotli v1.2.1 // indirect
+	github.com/dlclark/regexp2/v2 v2.2.1 // indirect
 	github.com/go-sourcemap/sourcemap v2.1.4+incompatible // indirect
-	github.com/google/pprof v0.0.0-20260302011040-a15ffb7f9dcc // indirect
-	github.com/klauspost/compress v1.18.5 // indirect
-	golang.org/x/mod v0.35.0 // indirect
-	golang.org/x/sync v0.20.0 // indirect
-	golang.org/x/sys v0.43.0 // indirect
-	golang.org/x/tools v0.44.0 // indirect
+	github.com/google/pprof v0.0.0-20260604005048-7023385849c0 // indirect
+	github.com/klauspost/compress v1.18.6 // indirect
+	golang.org/x/mod v0.37.0 // indirect
+	golang.org/x/sync v0.21.0 // indirect
+	golang.org/x/sys v0.46.0 // indirect
+	golang.org/x/tools v0.45.0 // indirect
 )

go_backend/go.sum

@@ -1,13 +1,13 @@
-github.com/Masterminds/semver/v3 v3.2.1 h1:RN9w6+7QoMeJVGyfmbcgs28Br8cvmnucEXnY0rYXWg0=
-github.com/Masterminds/semver/v3 v3.2.1/go.mod h1:qvl/7zhW3nngYb5+80sSMF+FG2BjYrf8m9wsX0PNOMQ=
-github.com/andybalholm/brotli v1.2.0 h1:ukwgCxwYrmACq68yiUqwIWnGY0cTPox/M94sVwToPjQ=
-github.com/andybalholm/brotli v1.2.0/go.mod h1:rzTDkvFWvIrjDXZHkuS16NPggd91W3kUSvPlQ1pLaKY=
+github.com/Masterminds/semver/v3 v3.5.0 h1:kQceYJfbupGfZOKZQg0kou0DgAKhzDg2NZPAwZ/2OOE=
+github.com/Masterminds/semver/v3 v3.5.0/go.mod h1:4V+yj/TJE1HU9XfppCwVMZq3I84lprf4nC11bSS5beM=
+github.com/andybalholm/brotli v1.2.1 h1:R+f5xP285VArJDRgowrfb9DqL18yVK0gKAW/F+eTWro=
+github.com/andybalholm/brotli v1.2.1/go.mod h1:rzTDkvFWvIrjDXZHkuS16NPggd91W3kUSvPlQ1pLaKY=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
-github.com/dlclark/regexp2 v1.11.5 h1:Q/sSnsKerHeCkc/jSTNq1oCm7KiVgUMZRDUoRu0JQZQ=
-github.com/dlclark/regexp2 v1.11.5/go.mod h1:DHkYz0B9wPfa6wondMfaivmHpzrQ3v9q8cnmRbL6yW8=
-github.com/dop251/goja v0.0.0-20260311135729-065cd970411c h1:OcLmPfx1T1RmZVHHFwWMPaZDdRf0DBMZOFMVWJa7Pdk=
-github.com/dop251/goja v0.0.0-20260311135729-065cd970411c/go.mod h1:MxLav0peU43GgvwVgNbLAj1s/bSGboKkhuULvq/7hx4=
+github.com/dlclark/regexp2/v2 v2.2.1 h1:mf4KkFUj0gJuarK8P+LgiS+Lit7m9N1yAwEfPbee7R0=
+github.com/dlclark/regexp2/v2 v2.2.1/go.mod h1:avUrQvPaLz2DrFNHJF0taWAFFX2C1GMSSoeiqFjcBmU=
+github.com/dop251/goja v0.0.0-20260607120635-348e6bea910d h1:xbM5U2EvWKkHxzEQJ2DEn20FwolWZahuTnVHr6WL3Q4=
+github.com/dop251/goja v0.0.0-20260607120635-348e6bea910d/go.mod h1:Sc+QOu1WruvaaeT/cxFez/pXHpI9ZDjg/E8QNfSVveI=
 github.com/go-flac/flacpicture/v2 v2.0.2 h1:HCaJIVZpxnpdWs6G3ECEVRelzqS5xOi1Ba1AGmtXbzE=
 github.com/go-flac/flacpicture/v2 v2.0.2/go.mod h1:DMZBPWPAmdLqNhqFSy5ZBs9wyBzOekXutGfP7/TFCuo=
 github.com/go-flac/flacvorbis/v2 v2.0.2 h1:xCL3OhxrxWkHrbWUBvGNe+6FQ03yLmBbz0v5z4V2PoQ=
@@ -16,12 +16,14 @@ github.com/go-flac/go-flac/v2 v2.0.4 h1:atf/kFa8U9idtkA//NO22XGr+MzQLeXZecnmP9sY
 github.com/go-flac/go-flac/v2 v2.0.4/go.mod h1:sYOlTKxutMW0RDYF+KlD6Zn+VOCZlIFQG/r/usPveCs=
 github.com/go-sourcemap/sourcemap v2.1.4+incompatible h1:a+iTbH5auLKxaNwQFg0B+TCYl6lbukKPc7b5x0n1s6Q=
 github.com/go-sourcemap/sourcemap v2.1.4+incompatible/go.mod h1:F8jJfvm2KbVjc5NqelyYJmf/v5J0dwNLS2mL4sNA1Jg=
+github.com/goccy/go-yaml v1.19.2 h1:PmFC1S6h8ljIz6gMRBopkjP1TVT7xuwrButHID66PoM=
+github.com/goccy/go-yaml v1.19.2/go.mod h1:XBurs7gK8ATbW4ZPGKgcbrY1Br56PdM69F7LkFRi1kA=
 github.com/google/go-cmp v0.6.0 h1:ofyhxvXcZhMsU5ulbFiLKl/XBFqE1GSq7atu8tAmTRI=
 github.com/google/go-cmp v0.6.0/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
-github.com/google/pprof v0.0.0-20260302011040-a15ffb7f9dcc h1:VBbFa1lDYWEeV5FZKUiYKYT0VxCp9twUmmaq9eb8sXw=
-github.com/google/pprof v0.0.0-20260302011040-a15ffb7f9dcc/go.mod h1:MxpfABSjhmINe3F1It9d+8exIHFvUqtLIRCdOGNXqiI=
-github.com/klauspost/compress v1.18.5 h1:/h1gH5Ce+VWNLSWqPzOVn6XBO+vJbCNGvjoaGBFW2IE=
-github.com/klauspost/compress v1.18.5/go.mod h1:cwPg85FWrGar70rWktvGQj8/hthj3wpl0PGDogxkrSQ=
+github.com/google/pprof v0.0.0-20260604005048-7023385849c0 h1:h1QTMDl6q9wDvDCJVpKQSjgleGFYnd2fOxmg2K+6BGE=
+github.com/google/pprof v0.0.0-20260604005048-7023385849c0/go.mod h1:MxpfABSjhmINe3F1It9d+8exIHFvUqtLIRCdOGNXqiI=
+github.com/klauspost/compress v1.18.6 h1:2jupLlAwFm95+YDR+NwD2MEfFO9d4z4Prjl1XXDjuao=
+github.com/klauspost/compress v1.18.6/go.mod h1:cwPg85FWrGar70rWktvGQj8/hthj3wpl0PGDogxkrSQ=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/refraction-networking/utls v1.8.2 h1:j4Q1gJj0xngdeH+Ox/qND11aEfhpgoEvV+S9iJ2IdQo=
@@ -30,23 +32,21 @@ github.com/stretchr/testify v1.10.0 h1:Xv5erBjTwe/5IxqUQTdXv5kgmIvbHo3QQyRwhJsOf
 github.com/stretchr/testify v1.10.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
 github.com/xyproto/randomstring v1.0.5 h1:YtlWPoRdgMu3NZtP45drfy1GKoojuR7hmRcnhZqKjWU=
 github.com/xyproto/randomstring v1.0.5/go.mod h1:rgmS5DeNXLivK7YprL0pY+lTuhNQW3iGxZ18UQApw/E=
-golang.org/x/crypto v0.50.0 h1:zO47/JPrL6vsNkINmLoo/PH1gcxpls50DNogFvB5ZGI=
-golang.org/x/crypto v0.50.0/go.mod h1:3muZ7vA7PBCE6xgPX7nkzzjiUq87kRItoJQM1Yo8S+Q=
-golang.org/x/mobile v0.0.0-20260410095206-2cfb76559b7b h1:Qt2eaXcZ8x20iAcoZ6AceeMMtnjuPHvC51KRCH1DKSQ=
-golang.org/x/mobile v0.0.0-20260410095206-2cfb76559b7b/go.mod h1:5Fu78lew5ucMXt8w2KYcwvxu2rkC/liHzUvaoiI+H/M=
-golang.org/x/mod v0.35.0 h1:Ww1D637e6Pg+Zb2KrWfHQUnH2dQRLBQyAtpr/haaJeM=
-golang.org/x/mod v0.35.0/go.mod h1:+GwiRhIInF8wPm+4AoT6L0FA1QWAad3OMdTRx4tFYlU=
-golang.org/x/net v0.53.0 h1:d+qAbo5L0orcWAr0a9JweQpjXF19LMXJE8Ey7hwOdUA=
-golang.org/x/net v0.53.0/go.mod h1:JvMuJH7rrdiCfbeHoo3fCQU24Lf5JJwT9W3sJFulfgs=
-golang.org/x/sync v0.20.0 h1:e0PTpb7pjO8GAtTs2dQ6jYa5BWYlMuX047Dco/pItO4=
-golang.org/x/sync v0.20.0/go.mod h1:9xrNwdLfx4jkKbNva9FpL6vEN7evnE43NNNJQ2LF3+0=
-golang.org/x/sys v0.43.0 h1:Rlag2XtaFTxp19wS8MXlJwTvoh8ArU6ezoyFsMyCTNI=
-golang.org/x/sys v0.43.0/go.mod h1:4GL1E5IUh+htKOUEOaiffhrAeqysfVGipDYzABqnCmw=
-golang.org/x/text v0.36.0 h1:JfKh3XmcRPqZPKevfXVpI1wXPTqbkE5f7JA92a55Yxg=
-golang.org/x/text v0.36.0/go.mod h1:NIdBknypM8iqVmPiuco0Dh6P5Jcdk8lJL0CUebqK164=
-golang.org/x/tools v0.44.0 h1:UP4ajHPIcuMjT1GqzDWRlalUEoY+uzoZKnhOjbIPD2c=
-golang.org/x/tools v0.44.0/go.mod h1:KA0AfVErSdxRZIsOVipbv3rQhVXTnlU6UhKxHd1seDI=
-gopkg.in/yaml.v2 v2.4.0 h1:D8xgwECY7CYvx+Y2n4sBz93Jn9JRvxdiyyo8CTfuKaY=
-gopkg.in/yaml.v2 v2.4.0/go.mod h1:RDklbk79AGWmwhnvt/jBztapEOGDOx6ZbXqjP6csGnQ=
+golang.org/x/crypto v0.53.0 h1:QZ4Muo8THX6CizN2vPPd5fBGHyogrdK9fG4wLPFUsto=
+golang.org/x/crypto v0.53.0/go.mod h1:DNLU434OwVakk9PzuwV8w62mAJpRJL3vsgcfp4Qnsio=
+golang.org/x/mobile v0.0.0-20260602190626-68735029466e h1:YxPXu/HWDTcSSrzSX+sCltsfcNCa/ZYVG43oslMouNU=
+golang.org/x/mobile v0.0.0-20260602190626-68735029466e/go.mod h1:ltIbhcRzKgwHa4ZxKJeiv0nyzcXUUYCqMyO0Y+vPmXw=
+golang.org/x/mod v0.37.0 h1:vF1DjpVEshcIqoEaauuHebaLk1O1forxjxBaVn884JQ=
+golang.org/x/mod v0.37.0/go.mod h1:m8S8VeM9r4dzDwjrKO0a1sZP3YjeMamRRlD+fmR2Q/0=
+golang.org/x/net v0.56.0 h1:Rw8j/hFzGvJUZwNBXnAtf5sVDVt+65SK2C7IxCxZt5o=
+golang.org/x/net v0.56.0/go.mod h1:D3Ku6r+V6JROoZK144D2XfMHFcMq/0zSfLelVTCFKec=
+golang.org/x/sync v0.21.0 h1:HLII4xRRTtCRkxYp4HNFF0Js/Og6q2i++KXbg0gHCwM=
+golang.org/x/sync v0.21.0/go.mod h1:9xrNwdLfx4jkKbNva9FpL6vEN7evnE43NNNJQ2LF3+0=
+golang.org/x/sys v0.46.0 h1:noSf2Fq6F8DBgS+LysIkx7rIExoNHJsxOAtPp4rthXw=
+golang.org/x/sys v0.46.0/go.mod h1:4GL1E5IUh+htKOUEOaiffhrAeqysfVGipDYzABqnCmw=
+golang.org/x/text v0.38.0 h1:sXmwo9DwP3OK9EZ7PqAdaooSGozfl/3a6/xJcbzPRhE=
+golang.org/x/text v0.38.0/go.mod h1:YXZt3QhHUKYT53r2lLKFIVi6Ao1jdzrTR/KQ09qyxF4=
+golang.org/x/tools v0.45.0 h1:18qN3FAooORvApf5XjCXgsuayZOEtXf6JK18I3+ONa8=
+golang.org/x/tools v0.45.0/go.mod h1:LuUGqqaXcXMEFEruIVJVm5mgDD8vww/z/SR1gQ4uE/0=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

go_backend/httputil.go

@@ -77,6 +77,26 @@ var sharedTransport = &http.Transport{
 	WriteBufferSize:       64 * 1024,
 	ReadBufferSize:        64 * 1024,
 	DisableCompression:    true,
+	TLSClientConfig:       newTLSCompatibilityConfig(false),
+}
+
+var extensionAPITransport = &http.Transport{
+	DialContext: (&net.Dialer{
+		Timeout:   30 * time.Second,
+		KeepAlive: 30 * time.Second,
+	}).DialContext,
+	MaxIdleConns:          100,
+	MaxIdleConnsPerHost:   10,
+	MaxConnsPerHost:       20,
+	IdleConnTimeout:       90 * time.Second,
+	TLSHandshakeTimeout:   10 * time.Second,
+	ExpectContinueTimeout: 1 * time.Second,
+	DisableKeepAlives:     false,
+	ForceAttemptHTTP2:     true,
+	WriteBufferSize:       64 * 1024,
+	ReadBufferSize:        64 * 1024,
+	DisableCompression:    false,
+	TLSClientConfig:       newTLSCompatibilityConfig(false),
 }
 
 var metadataTransport = &http.Transport{
@@ -95,6 +115,7 @@ var metadataTransport = &http.Transport{
 	WriteBufferSize:       32 * 1024,
 	ReadBufferSize:        32 * 1024,
 	DisableCompression:    true,
+	TLSClientConfig:       newTLSCompatibilityConfig(false),
 }
 
 var sharedClient = &http.Client{
@@ -131,6 +152,7 @@ func GetDownloadClient() *http.Client {
 
 func CloseIdleConnections() {
 	sharedTransport.CloseIdleConnections()
+	extensionAPITransport.CloseIdleConnections()
 	metadataTransport.CloseIdleConnections()
 }
 
@@ -143,6 +165,7 @@ func SetNetworkCompatibilityOptions(allowHTTP, insecureTLS bool) {
 	networkCompatibilityMu.Unlock()
 
 	applyTLSCompatibility(sharedTransport, insecureTLS)
+	applyTLSCompatibility(extensionAPITransport, insecureTLS)
 	applyTLSCompatibility(metadataTransport, insecureTLS)
 	CloseIdleConnections()
 
@@ -156,17 +179,7 @@ func GetNetworkCompatibilityOptions() NetworkCompatibilityOptions {
 }
 
 func applyTLSCompatibility(transport *http.Transport, insecureTLS bool) {
-	if insecureTLS {
-		cfg := &tls.Config{InsecureSkipVerify: true}
-		if transport.TLSClientConfig != nil {
-			cfg = transport.TLSClientConfig.Clone()
-			cfg.InsecureSkipVerify = true
-		}
-		transport.TLSClientConfig = cfg
-		return
-	}
-
-	transport.TLSClientConfig = nil
+	transport.TLSClientConfig = newTLSCompatibilityConfig(insecureTLS)
 }
 
 type compatibilityTransport struct {

go_backend/httputil_supplement_test.go

@@ -1,6 +1,8 @@
 package gobackend
 
 import (
+	"crypto/x509"
+	"encoding/pem"
 	"errors"
 	"io"
 	"net/http"
@@ -25,11 +27,34 @@ func TestHTTPUtilityHelpers(t *testing.T) {
 	if GetSharedClient() == nil || GetDownloadClient() == nil {
 		t.Fatal("expected shared clients")
 	}
+	if sharedTransport.TLSClientConfig == nil || sharedTransport.TLSClientConfig.RootCAs == nil {
+		t.Fatal("expected supplemental TLS root pool")
+	}
+	block, _ := pem.Decode([]byte(isrgRootX2PEM))
+	if block == nil {
+		t.Fatal("failed to decode ISRG Root X2")
+	}
+	rootX2, err := x509.ParseCertificate(block.Bytes)
+	if err != nil {
+		t.Fatalf("failed to parse ISRG Root X2: %v", err)
+	}
+	if _, err := rootX2.Verify(x509.VerifyOptions{
+		Roots:     supplementalRootCAs(),
+		KeyUsages: []x509.ExtKeyUsage{x509.ExtKeyUsageAny},
+	}); err != nil {
+		t.Fatalf("ISRG Root X2 should verify with supplemental roots: %v", err)
+	}
 	SetNetworkCompatibilityOptions(true, true)
 	if opts := GetNetworkCompatibilityOptions(); !opts.AllowHTTP || !opts.InsecureTLS {
 		t.Fatalf("network opts = %#v", opts)
 	}
+	if !sharedTransport.TLSClientConfig.InsecureSkipVerify {
+		t.Fatal("expected insecure TLS config to be applied")
+	}
 	SetNetworkCompatibilityOptions(false, false)
+	if sharedTransport.TLSClientConfig == nil || sharedTransport.TLSClientConfig.InsecureSkipVerify {
+		t.Fatal("expected secure TLS config to be restored")
+	}
 	if !canFallbackToHTTP(&http.Request{Method: http.MethodGet}) {
 		t.Fatal("GET should fallback")
 	}

go_backend/httputil_utls.go

@@ -42,9 +42,12 @@ func (t *utlsTransport) RoundTrip(req *http.Request) (*http.Response, error) {
 		return nil, err
 	}
 
+	opts := GetNetworkCompatibilityOptions()
 	tlsConn := utls.UClient(conn, &utls.Config{
-		ServerName: host,
-		NextProtos: []string{"h2", "http/1.1"},
+		RootCAs:            supplementalRootCAs(),
+		InsecureSkipVerify: opts.InsecureTLS,
+		ServerName:         host,
+		NextProtos:         []string{"h2", "http/1.1"},
 	}, utls.HelloChrome_Auto)
 
 	if err := tlsConn.Handshake(); err != nil {

go_backend/library_scan.go

@@ -68,12 +68,17 @@ var (
 var supportedAudioFormats = map[string]bool{
 	".flac": true,
 	".m4a":  true,
+	".mp4":  true,
+	".aac":  true,
 	".mp3":  true,
 	".opus": true,
 	".ogg":  true,
 	".ape":  true,
 	".wv":   true,
 	".mpc":  true,
+	".wav":  true,
+	".aiff": true,
+	".aif":  true,
 	".cue":  true,
 }
 
@@ -87,6 +92,19 @@ type scannedCueFileInfo struct {
 	audioPath string
 }
 
+func isLibraryStagingFile(path string) bool {
+	name := strings.ToLower(filepath.Base(path))
+	if strings.HasSuffix(name, ".partial") {
+		return true
+	}
+	for ext := range supportedAudioFormats {
+		if strings.HasSuffix(name, ".partial"+ext) {
+			return true
+		}
+	}
+	return false
+}
+
 func collectLibraryAudioFiles(folderPath string, cancelCh <-chan struct{}) ([]libraryAudioFileInfo, error) {
 	var files []libraryAudioFileInfo
 
@@ -104,6 +122,9 @@ func collectLibraryAudioFiles(folderPath string, cancelCh <-chan struct{}) ([]li
 		if entry.IsDir() {
 			return nil
 		}
+		if isLibraryStagingFile(path) {
+			return nil
+		}
 
 		ext := strings.ToLower(filepath.Ext(path))
 		if !supportedAudioFormats[ext] {
@@ -314,7 +335,7 @@ func scanAudioFileWithKnownModTimeAndDisplayNameAndCoverCacheKey(filePath, displ
 	switch ext {
 	case ".flac":
 		return scanFLACFile(filePath, result, displayNameHint)
-	case ".m4a":
+	case ".m4a", ".mp4", ".aac":
 		return scanM4AFile(filePath, result, displayNameHint)
 	case ".mp3":
 		return scanMP3File(filePath, result, displayNameHint)
@@ -322,6 +343,10 @@ func scanAudioFileWithKnownModTimeAndDisplayNameAndCoverCacheKey(filePath, displ
 		return scanOggFile(filePath, result, displayNameHint)
 	case ".ape", ".wv", ".mpc":
 		return scanAPEFile(filePath, result, displayNameHint)
+	case ".wav":
+		return scanWAVFile(filePath, result, displayNameHint)
+	case ".aiff", ".aif", ".aifc":
+		return scanAIFFFile(filePath, result, displayNameHint)
 	default:
 		return scanFromFilename(filePath, displayNameHint, result)
 	}
@@ -394,7 +419,6 @@ func scanM4AFile(filePath string, result *LibraryScanResult, displayNameHint str
 	metadata, err := ReadM4ATags(filePath)
 	if err != nil {
 		GoLog("[LibraryScan] M4A read error for %s: %v\n", filePath, err)
-		return scanFromFilename(filePath, displayNameHint, result)
 	}
 
 	if metadata != nil {
@@ -421,12 +445,54 @@ func scanM4AFile(filePath string, result *LibraryScanResult, displayNameHint str
 	if err == nil {
 		result.BitDepth = quality.BitDepth
 		result.SampleRate = quality.SampleRate
+		result.Duration = quality.Duration
+		if quality.Bitrate > 0 {
+			result.Bitrate = quality.Bitrate
+		}
+		if format := libraryFormatForM4ACodec(quality.Codec); format != "" {
+			result.Format = format
+			if isLosslessLibraryFormat(format) {
+				result.Bitrate = 0
+			}
+		}
+	}
+
+	if metadata == nil {
+		return scanFromFilename(filePath, displayNameHint, result)
 	}
 
 	applyDefaultLibraryMetadata(filePath, displayNameHint, result)
 	return result, nil
 }
 
+func libraryFormatForM4ACodec(codec string) string {
+	switch strings.ToLower(strings.TrimSpace(codec)) {
+	case "flac":
+		return "flac"
+	case "alac":
+		return "alac"
+	case "eac3", "ec-3":
+		return "eac3"
+	case "ac3", "ac-3":
+		return "ac3"
+	case "ac4", "ac-4":
+		return "ac4"
+	case "aac", "mp4a":
+		return "m4a"
+	default:
+		return ""
+	}
+}
+
+func isLosslessLibraryFormat(format string) bool {
+	switch strings.ToLower(strings.TrimSpace(format)) {
+	case "flac", "alac", "wav", "aiff", "aif", "aifc":
+		return true
+	default:
+		return false
+	}
+}
+
 func scanMP3File(filePath string, result *LibraryScanResult, displayNameHint string) (*LibraryScanResult, error) {
 	metadata, err := ReadID3Tags(filePath)
 	if err != nil {

go_backend/library_scan_supplement_test.go

@@ -42,6 +42,14 @@ func TestLibraryScanFullIncrementalAndMetadataFallbacks(t *testing.T) {
 	if err := os.WriteFile(filepath.Join(albumDir, "ignored.txt"), []byte("ignore"), 0600); err != nil {
 		t.Fatal(err)
 	}
+	legacyPartialPath := filepath.Join(albumDir, "Artist - Song.partial.flac")
+	if err := os.WriteFile(legacyPartialPath, []byte("partial flac"), 0600); err != nil {
+		t.Fatal(err)
+	}
+	newPartialPath := filepath.Join(albumDir, "Artist - Song.flac.partial")
+	if err := os.WriteFile(newPartialPath, []byte("partial flac"), 0600); err != nil {
+		t.Fatal(err)
+	}
 
 	files, err := collectLibraryAudioFiles(dir, make(chan struct{}))
 	if err != nil {
@@ -50,6 +58,11 @@ func TestLibraryScanFullIncrementalAndMetadataFallbacks(t *testing.T) {
 	if len(files) < 4 {
 		t.Fatalf("files = %#v", files)
 	}
+	for _, file := range files {
+		if file.path == legacyPartialPath || file.path == newPartialPath {
+			t.Fatalf("staging file should be ignored: %#v", files)
+		}
+	}
 	cancelCh := make(chan struct{})
 	close(cancelCh)
 	if _, err := collectLibraryAudioFiles(dir, cancelCh); err == nil {

go_backend/lyrics.go

@@ -26,6 +26,12 @@ const (
 	LyricsProviderMusixmatch = "musixmatch"
 	LyricsProviderAppleMusic = "apple_music"
 	LyricsProviderQQMusic    = "qqmusic"
+	LyricsProviderSpotify    = "spotify"
+	LyricsProviderDeezer     = "deezer"
+	LyricsProviderYouTube    = "youtube"
+	LyricsProviderKugou      = "kugou"
+	LyricsProviderGenius     = "genius"
+	LyricsProviderLyricsPlus = "lyricsplus"
 )
 
 var DefaultLyricsProviders = []string{
@@ -68,6 +74,7 @@ type LyricsFetchOptions struct {
 	IncludeTranslationNetease  bool   `json:"include_translation_netease"`
 	IncludeRomanizationNetease bool   `json:"include_romanization_netease"`
 	MultiPersonWordByWord      bool   `json:"multi_person_word_by_word"`
+	AppleElrcWordSync          bool   `json:"apple_elrc_word_sync"`
 	MusixmatchLanguage         string `json:"musixmatch_language,omitempty"`
 }
 
@@ -75,6 +82,7 @@ var defaultLyricsFetchOptions = LyricsFetchOptions{
 	IncludeTranslationNetease:  false,
 	IncludeRomanizationNetease: false,
 	MultiPersonWordByWord:      true,
+	AppleElrcWordSync:          false,
 	MusixmatchLanguage:         "",
 }
 
@@ -100,6 +108,12 @@ func SetLyricsProviderOrder(providers []string) {
 		LyricsProviderMusixmatch: true,
 		LyricsProviderAppleMusic: true,
 		LyricsProviderQQMusic:    true,
+		LyricsProviderSpotify:    true,
+		LyricsProviderDeezer:     true,
+		LyricsProviderYouTube:    true,
+		LyricsProviderKugou:      true,
+		LyricsProviderGenius:     true,
+		LyricsProviderLyricsPlus: true,
 	}
 
 	var valid []string
@@ -130,10 +144,16 @@ func GetLyricsProviderOrder() []string {
 func GetAvailableLyricsProviders() []map[string]interface{} {
 	return []map[string]interface{}{
 		{"id": LyricsProviderLRCLIB, "name": "LRCLIB", "has_proxy_dependency": false, "description": "Open-source synced lyrics database"},
-		{"id": LyricsProviderNetease, "name": "Netease", "has_proxy_dependency": true, "description": "NetEase Cloud Music lyrics via Paxsenix"},
-		{"id": LyricsProviderMusixmatch, "name": "Musixmatch", "has_proxy_dependency": true, "description": "Musixmatch lyrics via Paxsenix"},
-		{"id": LyricsProviderAppleMusic, "name": "Apple Music", "has_proxy_dependency": true, "description": "Apple Music synced lyrics via Paxsenix"},
-		{"id": LyricsProviderQQMusic, "name": "QQ Music", "has_proxy_dependency": true, "description": "QQ Music lyrics via Paxsenix"},
+		{"id": LyricsProviderNetease, "name": "Netease", "has_proxy_dependency": true, "description": "NetEase Cloud Music lyrics"},
+		{"id": LyricsProviderMusixmatch, "name": "Musixmatch", "has_proxy_dependency": true, "description": "Musixmatch lyrics"},
+		{"id": LyricsProviderAppleMusic, "name": "Apple Music", "has_proxy_dependency": true, "description": "Apple Music synced lyrics"},
+		{"id": LyricsProviderQQMusic, "name": "QQ Music", "has_proxy_dependency": true, "description": "QQ Music lyrics"},
+		{"id": LyricsProviderSpotify, "name": "Spotify", "has_proxy_dependency": true, "description": "Spotify synced lyrics"},
+		{"id": LyricsProviderDeezer, "name": "Deezer", "has_proxy_dependency": true, "description": "Deezer lyrics"},
+		{"id": LyricsProviderYouTube, "name": "YouTube", "has_proxy_dependency": true, "description": "YouTube lyrics"},
+		{"id": LyricsProviderKugou, "name": "Kugou", "has_proxy_dependency": true, "description": "Kugou lyrics"},
+		{"id": LyricsProviderGenius, "name": "Genius", "has_proxy_dependency": true, "description": "Genius lyrics"},
+		{"id": LyricsProviderLyricsPlus, "name": "LyricsPlus", "has_proxy_dependency": true, "description": "Word-by-word karaoke lyrics (Apple/Musixmatch/Spotify/QQ)"},
 	}
 }
 
@@ -151,12 +171,18 @@ func SetLyricsFetchOptions(opts LyricsFetchOptions) {
 
 	lyricsFetchOptionsMu.Lock()
 	defer lyricsFetchOptionsMu.Unlock()
+	changed := lyricsFetchOptions != normalized
 	lyricsFetchOptions = normalized
 
-	GoLog("[Lyrics] Fetch options set: translation=%v romanization=%v multi_person=%v musixmatch_lang=%q\n",
+	if changed {
+		globalLyricsCache.ClearAll()
+	}
+
+	GoLog("[Lyrics] Fetch options set: translation=%v romanization=%v multi_person=%v apple_elrc=%v musixmatch_lang=%q\n",
 		normalized.IncludeTranslationNetease,
 		normalized.IncludeRomanizationNetease,
 		normalized.MultiPersonWordByWord,
+		normalized.AppleElrcWordSync,
 		normalized.MusixmatchLanguage,
 	)
 }
@@ -530,9 +556,9 @@ func (c *LyricsClient) FetchLyricsAllSources(spotifyID, trackName, artistName st
 
 		case LyricsProviderAppleMusic:
 			appleClient := NewAppleMusicClient()
-			lyrics, err = appleClient.FetchLyrics(trackName, primaryArtist, durationSec, fetchOptions.MultiPersonWordByWord)
+			lyrics, err = appleClient.FetchLyrics(trackName, primaryArtist, durationSec, fetchOptions.MultiPersonWordByWord, fetchOptions.AppleElrcWordSync)
 			if err != nil && primaryArtist != artistName {
-				lyrics, err = appleClient.FetchLyrics(trackName, artistName, durationSec, fetchOptions.MultiPersonWordByWord)
+				lyrics, err = appleClient.FetchLyrics(trackName, artistName, durationSec, fetchOptions.MultiPersonWordByWord, fetchOptions.AppleElrcWordSync)
 			}
 
 		case LyricsProviderQQMusic:
@@ -542,6 +568,84 @@ func (c *LyricsClient) FetchLyricsAllSources(spotifyID, trackName, artistName st
 				lyrics, err = qqClient.FetchLyrics(trackName, artistName, durationSec, fetchOptions.MultiPersonWordByWord)
 			}
 
+		case LyricsProviderSpotify:
+			spotifyClient := NewSpotifyLyricsClient()
+			lyrics, err = spotifyClient.FetchLyrics(spotifyID, trackName, primaryArtist, durationSec)
+			if err != nil && primaryArtist != artistName {
+				lyrics, err = spotifyClient.FetchLyrics(spotifyID, trackName, artistName, durationSec)
+			}
+			if err != nil && simplifiedTrack != trackName {
+				lyrics, err = spotifyClient.FetchLyrics("", simplifiedTrack, primaryArtist, durationSec)
+			}
+
+		case LyricsProviderDeezer:
+			deezerClient := NewDeezerLyricsClient()
+			lyrics, err = deezerClient.FetchLyrics(spotifyID, trackName, primaryArtist, durationSec)
+			if err != nil && primaryArtist != artistName {
+				lyrics, err = deezerClient.FetchLyrics(spotifyID, trackName, artistName, durationSec)
+			}
+
+		case LyricsProviderYouTube:
+			youtubeClient := NewYouTubeLyricsClient()
+			lyrics, err = youtubeClient.FetchLyrics(trackName, primaryArtist, durationSec)
+			if err != nil && primaryArtist != artistName {
+				lyrics, err = youtubeClient.FetchLyrics(trackName, artistName, durationSec)
+			}
+			if err != nil && simplifiedTrack != trackName {
+				lyrics, err = youtubeClient.FetchLyrics(simplifiedTrack, primaryArtist, durationSec)
+			}
+
+		case LyricsProviderKugou:
+			kugouClient := NewKugouLyricsClient()
+			lyrics, err = kugouClient.FetchLyrics(trackName, primaryArtist, durationSec)
+			if err != nil && primaryArtist != artistName {
+				lyrics, err = kugouClient.FetchLyrics(trackName, artistName, durationSec)
+			}
+			if err != nil && simplifiedTrack != trackName {
+				lyrics, err = kugouClient.FetchLyrics(simplifiedTrack, primaryArtist, durationSec)
+			}
+
+		case LyricsProviderGenius:
+			geniusClient := NewGeniusLyricsClient()
+			lyrics, err = geniusClient.FetchLyrics(trackName, primaryArtist, durationSec)
+			if err != nil && primaryArtist != artistName {
+				lyrics, err = geniusClient.FetchLyrics(trackName, artistName, durationSec)
+			}
+			if err != nil && simplifiedTrack != trackName {
+				lyrics, err = geniusClient.FetchLyrics(simplifiedTrack, primaryArtist, durationSec)
+			}
+
+		case LyricsProviderLyricsPlus:
+			lyricsPlusClient := NewLyricsPlusClient()
+			lyrics, err = lyricsPlusClient.FetchLyrics(
+				trackName,
+				primaryArtist,
+				"",
+				durationSec,
+				fetchOptions.MultiPersonWordByWord,
+				fetchOptions.AppleElrcWordSync,
+			)
+			if err != nil && primaryArtist != artistName {
+				lyrics, err = lyricsPlusClient.FetchLyrics(
+					trackName,
+					artistName,
+					"",
+					durationSec,
+					fetchOptions.MultiPersonWordByWord,
+					fetchOptions.AppleElrcWordSync,
+				)
+			}
+			if err != nil && simplifiedTrack != trackName {
+				lyrics, err = lyricsPlusClient.FetchLyrics(
+					simplifiedTrack,
+					primaryArtist,
+					"",
+					durationSec,
+					fetchOptions.MultiPersonWordByWord,
+					fetchOptions.AppleElrcWordSync,
+				)
+			}
+
 		default:
 			GoLog("[Lyrics] Unknown provider: %s, skipping\n", providerName)
 			continue
@@ -773,6 +877,41 @@ func msToLRCTimestampInline(ms int64) string {
 	return fmt.Sprintf("%02d:%02d.%02d", minutes, seconds, centiseconds)
 }
 
+// extractLyricsSourceFromLRC reads the provider recorded in the LRC [by:] tag,
+// e.g. "[by:SpotiFLAC-Mobile (source: LRCLIB)]". Returns "" when absent.
+const lrcSourceMarker = "(source: "
+
+func lyricsSourceUsesPaxsenix(source string) bool {
+	s := strings.ToLower(strings.TrimSpace(source))
+	if s == "" {
+		return false
+	}
+	if strings.HasPrefix(s, "lrclib") ||
+		strings.HasPrefix(s, "extension:") ||
+		strings.HasPrefix(s, "heuristic") {
+		return false
+	}
+	return true
+}
+
+func extractLyricsSourceFromLRC(lrc string) string {
+	for _, line := range strings.Split(lrc, "\n") {
+		trimmed := strings.TrimSpace(line)
+		if !strings.HasPrefix(strings.ToLower(trimmed), "[by:") {
+			continue
+		}
+		idx := strings.Index(trimmed, lrcSourceMarker)
+		if idx < 0 {
+			return ""
+		}
+		rest := strings.TrimSpace(trimmed[idx+len(lrcSourceMarker):])
+		rest = strings.TrimSuffix(rest, "]")
+		rest = strings.TrimSuffix(rest, ")")
+		return strings.TrimSpace(rest)
+	}
+	return ""
+}
+
 func convertToLRCWithMetadata(lyrics *LyricsResponse, trackName, artistName string) string {
 	if lyrics == nil || len(lyrics.Lines) == 0 {
 		return ""
@@ -782,7 +921,21 @@ func convertToLRCWithMetadata(lyrics *LyricsResponse, trackName, artistName stri
 
 	builder.WriteString(fmt.Sprintf("[ti:%s]\n", trackName))
 	builder.WriteString(fmt.Sprintf("[ar:%s]\n", artistName))
-	builder.WriteString("[by:Implemented by SpotiFLAC-Mobile using Paxsenix API]\n")
+	source := strings.TrimSpace(lyrics.Source)
+	if source == "" {
+		source = strings.TrimSpace(lyrics.Provider)
+	}
+	credit := "SpotiFLAC-Mobile"
+	if lyricsSourceUsesPaxsenix(source) {
+		credit = "SpotiFLAC-Mobile via Paxsenix API"
+	}
+	if source == "" {
+		builder.WriteString(fmt.Sprintf("[by:%s]\n", credit))
+	} else {
+		builder.WriteString(
+			fmt.Sprintf("[by:%s %s%s)]\n", credit, lrcSourceMarker, source),
+		)
+	}
 	builder.WriteString("\n")
 
 	if lyrics.SyncType == "LINE_SYNCED" {

go_backend/lyrics_apple.go

@@ -7,7 +7,9 @@ import (
 	"math"
 	"net/http"
 	"net/url"
+	"regexp"
 	"strings"
+	"sync"
 	"time"
 )
 
@@ -15,6 +17,8 @@ type AppleMusicClient struct {
 	httpClient *http.Client
 }
 
+const appleMusicCatalogBaseURL = "https://amp-api.music.apple.com/v1/catalog/us"
+
 type appleMusicSearchResult struct {
 	ID         string `json:"id"`
 	SongName   string `json:"songName"`
@@ -23,9 +27,33 @@ type appleMusicSearchResult struct {
 	Duration   int    `json:"duration"`
 }
 
+type appleMusicCatalogSearchResponse struct {
+	Results struct {
+		Songs *struct {
+			Data []struct {
+				ID string `json:"id"`
+			} `json:"data"`
+		} `json:"songs"`
+	} `json:"results"`
+	Resources *struct {
+		Songs map[string]struct {
+			Attributes struct {
+				Name             string `json:"name"`
+				ArtistName       string `json:"artistName"`
+				AlbumName        string `json:"albumName"`
+				DurationInMillis int    `json:"durationInMillis"`
+			} `json:"attributes"`
+		} `json:"songs"`
+	} `json:"resources"`
+}
+
 type paxResponse struct {
-	Type    string      `json:"type"`    // "Syllable" or "Line"
-	Content []paxLyrics `json:"content"` // List of lyric lines
+	Type            string      `json:"type"` // "Syllable" or "Line"
+	Content         []paxLyrics `json:"content"`
+	ELRC            string      `json:"elrc"`
+	ELRCMultiPerson string      `json:"elrcMultiPerson"`
+	Plain           string      `json:"plain"`
+	TTMLContent     string      `json:"ttmlContent"`
 }
 
 type paxLyrics struct {
@@ -44,6 +72,11 @@ type paxLyricDetail struct {
 	EndTime   *int   `json:"endtime"`
 }
 
+var (
+	appleMusicTokenMu     sync.Mutex
+	appleMusicCachedToken string
+)
+
 func NewAppleMusicClient() *AppleMusicClient {
 	return &AppleMusicClient{
 		httpClient: NewMetadataHTTPClient(20 * time.Second),
@@ -100,36 +133,164 @@ func selectBestAppleMusicSearchResult(results []appleMusicSearchResult, trackNam
 	return &results[bestIndex]
 }
 
+func (c *AppleMusicClient) getAppleMusicToken() (string, error) {
+	appleMusicTokenMu.Lock()
+	defer appleMusicTokenMu.Unlock()
+
+	if appleMusicCachedToken != "" {
+		return appleMusicCachedToken, nil
+	}
+
+	req, err := http.NewRequest("GET", "https://beta.music.apple.com", nil)
+	if err != nil {
+		return "", fmt.Errorf("failed to create apple music page request: %w", err)
+	}
+	req.Header.Set("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36")
+
+	resp, err := c.httpClient.Do(req)
+	if err != nil {
+		return "", fmt.Errorf("failed to fetch apple music page: %w", err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		return "", fmt.Errorf("apple music page returned HTTP %d", resp.StatusCode)
+	}
+
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return "", fmt.Errorf("failed to read apple music page: %w", err)
+	}
+
+	indexPath := regexp.MustCompile(`/assets/index~[^"' <]+\.js`).FindString(string(body))
+	if indexPath == "" {
+		return "", fmt.Errorf("apple music index script not found")
+	}
+
+	jsReq, err := http.NewRequest("GET", "https://beta.music.apple.com"+indexPath, nil)
+	if err != nil {
+		return "", fmt.Errorf("failed to create apple music script request: %w", err)
+	}
+	jsReq.Header.Set("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36")
+
+	jsResp, err := c.httpClient.Do(jsReq)
+	if err != nil {
+		return "", fmt.Errorf("failed to fetch apple music script: %w", err)
+	}
+	defer jsResp.Body.Close()
+
+	if jsResp.StatusCode != http.StatusOK {
+		return "", fmt.Errorf("apple music script returned HTTP %d", jsResp.StatusCode)
+	}
+
+	jsBody, err := io.ReadAll(jsResp.Body)
+	if err != nil {
+		return "", fmt.Errorf("failed to read apple music script: %w", err)
+	}
+
+	token := regexp.MustCompile(`eyJh[^"' <]+`).FindString(string(jsBody))
+	if token == "" {
+		return "", fmt.Errorf("apple music token not found")
+	}
+
+	appleMusicCachedToken = token
+	return token, nil
+}
+
+func clearAppleMusicToken() {
+	appleMusicTokenMu.Lock()
+	defer appleMusicTokenMu.Unlock()
+	appleMusicCachedToken = ""
+}
+
+func (c *AppleMusicClient) searchSongWithToken(token, query string) ([]appleMusicSearchResult, error) {
+	params := url.Values{}
+	params.Set("term", query)
+	params.Set("types", "songs")
+	params.Set("limit", "25")
+	params.Set("l", "en-US")
+	params.Set("platform", "web")
+	params.Set("format[resources]", "map")
+	params.Set("include[songs]", "artists")
+	params.Set("extend", "artistUrl")
+
+	searchURL := appleMusicCatalogBaseURL + "/search?" + params.Encode()
+	req, err := http.NewRequest("GET", searchURL, nil)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create apple music catalog request: %w", err)
+	}
+
+	req.Header.Set("Authorization", "Bearer "+token)
+	req.Header.Set("Origin", "https://music.apple.com")
+	req.Header.Set("Referer", "https://music.apple.com/")
+	req.Header.Set("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:95.0) Gecko/20100101 Firefox/95.0")
+	req.Header.Set("Accept", "application/json")
+	req.Header.Set("Accept-Language", "en-US,en;q=0.5")
+	req.Header.Set("x-apple-renewal", "true")
+
+	resp, err := c.httpClient.Do(req)
+	if err != nil {
+		return nil, fmt.Errorf("apple music catalog search failed: %w", err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode == http.StatusUnauthorized {
+		return nil, fmt.Errorf("apple music catalog search unauthorized")
+	}
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("apple music catalog search returned HTTP %d", resp.StatusCode)
+	}
+
+	var searchResp appleMusicCatalogSearchResponse
+	if err := json.NewDecoder(resp.Body).Decode(&searchResp); err != nil {
+		return nil, fmt.Errorf("failed to decode apple music catalog response: %w", err)
+	}
+
+	if searchResp.Results.Songs == nil || searchResp.Resources == nil {
+		return nil, nil
+	}
+
+	results := make([]appleMusicSearchResult, 0, len(searchResp.Results.Songs.Data))
+	for _, item := range searchResp.Results.Songs.Data {
+		detail, ok := searchResp.Resources.Songs[item.ID]
+		if !ok {
+			continue
+		}
+		attr := detail.Attributes
+		results = append(results, appleMusicSearchResult{
+			ID:         item.ID,
+			SongName:   attr.Name,
+			ArtistName: attr.ArtistName,
+			AlbumName:  attr.AlbumName,
+			Duration:   attr.DurationInMillis,
+		})
+	}
+
+	return results, nil
+}
+
 func (c *AppleMusicClient) SearchSong(trackName, artistName string, durationSec float64) (string, error) {
 	query := trackName + " " + artistName
 	if strings.TrimSpace(query) == "" {
 		return "", fmt.Errorf("empty search query")
 	}
 
-	encodedQuery := url.QueryEscape(query)
-	searchURL := fmt.Sprintf("https://lyrics.paxsenix.org/apple-music/search?q=%s", encodedQuery)
-
-	req, err := http.NewRequest("GET", searchURL, nil)
+	token, err := c.getAppleMusicToken()
 	if err != nil {
-		return "", fmt.Errorf("failed to create request: %w", err)
+		return "", err
 	}
 
-	req.Header.Set("User-Agent", appUserAgent())
-	req.Header.Set("Accept", "application/json")
-
-	resp, err := c.httpClient.Do(req)
+	searchResp, err := c.searchSongWithToken(token, strings.TrimSpace(query))
+	if err != nil && strings.Contains(strings.ToLower(err.Error()), "unauthorized") {
+		clearAppleMusicToken()
+		token, tokenErr := c.getAppleMusicToken()
+		if tokenErr != nil {
+			return "", tokenErr
+		}
+		searchResp, err = c.searchSongWithToken(token, strings.TrimSpace(query))
+	}
 	if err != nil {
-		return "", fmt.Errorf("apple music search failed: %w", err)
-	}
-	defer resp.Body.Close()
-
-	if resp.StatusCode != 200 {
-		return "", fmt.Errorf("apple music search returned HTTP %d", resp.StatusCode)
-	}
-
-	var searchResp []appleMusicSearchResult
-	if err := json.NewDecoder(resp.Body).Decode(&searchResp); err != nil {
-		return "", fmt.Errorf("failed to decode apple music response: %w", err)
+		return "", err
 	}
 
 	best := selectBestAppleMusicSearchResult(searchResp, trackName, artistName, durationSec)
@@ -173,25 +334,50 @@ func (c *AppleMusicClient) FetchLyricsByID(songID string) (string, error) {
 	return bodyStr, nil
 }
 
-func formatPaxLyricsToLRC(rawJSON string, multiPersonWordByWord bool) (string, error) {
+func formatPaxLyricsToLRC(rawJSON string, multiPersonWordByWord bool, preserveWordTiming bool) (string, error) {
+	var stringPayload string
+	if err := json.Unmarshal([]byte(rawJSON), &stringPayload); err == nil {
+		stringPayload = strings.TrimSpace(stringPayload)
+		if stringPayload != "" {
+			return stringPayload, nil
+		}
+	}
+
 	var paxResp paxResponse
-	if err := json.Unmarshal([]byte(rawJSON), &paxResp); err == nil && paxResp.Content != nil {
-		return formatPaxContent(paxResp.Type, paxResp.Content, multiPersonWordByWord), nil
+	if err := json.Unmarshal([]byte(rawJSON), &paxResp); err == nil &&
+		(paxResp.Content != nil ||
+			strings.TrimSpace(paxResp.ELRCMultiPerson) != "" ||
+			strings.TrimSpace(paxResp.ELRC) != "" ||
+			strings.TrimSpace(paxResp.Plain) != "" ||
+			strings.TrimSpace(paxResp.TTMLContent) != "") {
+		if preserveWordTiming && multiPersonWordByWord && strings.TrimSpace(paxResp.ELRCMultiPerson) != "" {
+			return strings.TrimSpace(paxResp.ELRCMultiPerson), nil
+		}
+		if preserveWordTiming && strings.TrimSpace(paxResp.ELRC) != "" {
+			return strings.TrimSpace(paxResp.ELRC), nil
+		}
+		if strings.TrimSpace(paxResp.Plain) != "" && len(paxResp.Content) == 0 {
+			return strings.TrimSpace(paxResp.Plain), nil
+		}
+		if len(paxResp.Content) == 0 {
+			return "", fmt.Errorf("unsupported apple music lyrics payload")
+		}
+		return formatPaxContent(paxResp.Type, paxResp.Content, multiPersonWordByWord, preserveWordTiming), nil
 	}
 
 	var directLyrics []paxLyrics
 	if err := json.Unmarshal([]byte(rawJSON), &directLyrics); err == nil && len(directLyrics) > 0 {
-		return formatPaxContent("Syllable", directLyrics, multiPersonWordByWord), nil
+		return formatPaxContent("Syllable", directLyrics, multiPersonWordByWord, preserveWordTiming), nil
 	}
 
 	return "", fmt.Errorf("failed to parse pax lyrics response")
 }
 
-func appendPaxLyricDetail(builder *strings.Builder, details []paxLyricDetail) {
+func appendPaxLyricDetail(builder *strings.Builder, details []paxLyricDetail, preserveWordTiming bool) {
 	lastStart := ""
 
 	for _, syllable := range details {
-		if syllable.Timestamp != nil {
+		if preserveWordTiming && syllable.Timestamp != nil {
 			start := fmt.Sprintf("<%s>", msToLRCTimestampInline(int64(*syllable.Timestamp)))
 			if start != lastStart {
 				builder.WriteString(start)
@@ -204,13 +390,13 @@ func appendPaxLyricDetail(builder *strings.Builder, details []paxLyricDetail) {
 			builder.WriteString(" ")
 		}
 
-		if syllable.EndTime != nil {
+		if preserveWordTiming && syllable.EndTime != nil {
 			builder.WriteString(fmt.Sprintf("<%s>", msToLRCTimestampInline(int64(*syllable.EndTime))))
 		}
 	}
 }
 
-func formatPaxContent(lyricsType string, content []paxLyrics, multiPersonWordByWord bool) string {
+func formatPaxContent(lyricsType string, content []paxLyrics, multiPersonWordByWord bool, preserveWordTiming bool) string {
 	var sb strings.Builder
 
 	for i, line := range content {
@@ -230,11 +416,11 @@ func formatPaxContent(lyricsType string, content []paxLyrics, multiPersonWordByW
 				}
 			}
 
-			appendPaxLyricDetail(&sb, line.Text)
+			appendPaxLyricDetail(&sb, line.Text, preserveWordTiming)
 
 			if line.Background && multiPersonWordByWord && len(line.BackgroundText) > 0 {
 				sb.WriteString("\n[bg:")
-				appendPaxLyricDetail(&sb, line.BackgroundText)
+				appendPaxLyricDetail(&sb, line.BackgroundText, preserveWordTiming)
 				sb.WriteString("]")
 			}
 		} else {
@@ -253,6 +439,7 @@ func (c *AppleMusicClient) FetchLyrics(
 	artistName string,
 	durationSec float64,
 	multiPersonWordByWord bool,
+	preserveWordTiming bool,
 ) (*LyricsResponse, error) {
 	songID, err := c.SearchSong(trackName, artistName, durationSec)
 	if err != nil {
@@ -267,8 +454,12 @@ func (c *AppleMusicClient) FetchLyrics(
 		return nil, fmt.Errorf("apple music proxy returned non-lyric payload: %s", errMsg)
 	}
 
-	lrcText, err := formatPaxLyricsToLRC(rawLyrics, multiPersonWordByWord)
+	lrcText, err := formatPaxLyricsToLRC(rawLyrics, multiPersonWordByWord, preserveWordTiming)
 	if err != nil {
+		trimmedRaw := strings.TrimSpace(rawLyrics)
+		if strings.HasPrefix(trimmedRaw, "{") || strings.HasPrefix(trimmedRaw, "[") {
+			return nil, err
+		}
 		lrcText = rawLyrics
 	}
 

go_backend/lyrics_lyricsplus.go

@@ -0,0 +1,243 @@
+package gobackend
+
+import (
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"net/url"
+	"strconv"
+	"strings"
+	"time"
+)
+
+// LyricsPlus (KPOE) provider.
+//
+// LyricsPlus aggregates word-by-word ("karaoke") synced lyrics from Apple
+// Music, Musixmatch, Spotify and QQ Music via a community-run backend. It
+// frequently has word-level timing for tracks that other providers only offer
+// line-synced or not at all.
+//
+// API: GET {server}/v2/lyrics/get?title=&artist=&album=&duration=&isrc=
+// The response is the KPOE JSON format which we convert into the same enhanced
+// LRC text the Apple/QQ providers emit, so embedding/export behaves identically.
+
+// Public LyricsPlus / KPOE servers (mirrors). Tried in order with failover.
+// Sourced from the upstream YouLy+ client server list.
+var lyricsPlusServers = []string{
+	"https://lyricsplus.prjktla.my.id",
+	"https://lyricsplus.atomix.one",
+	"https://lyricsplus.binimum.org",
+	"https://lyricsplus.prjktla.workers.dev",
+	"https://lyricsplus-seven.vercel.app",
+	"https://lyrics-plus-backend.vercel.app",
+}
+
+type LyricsPlusClient struct {
+	httpClient *http.Client
+}
+
+func NewLyricsPlusClient() *LyricsPlusClient {
+	return &LyricsPlusClient{httpClient: NewMetadataHTTPClient(15 * time.Second)}
+}
+
+type lyricsPlusSyllable struct {
+	Text         string  `json:"text"`
+	Time         float64 `json:"time"`     // absolute ms
+	Duration     float64 `json:"duration"` // ms
+	IsBackground bool    `json:"isBackground"`
+}
+
+type lyricsPlusLine struct {
+	Time     float64              `json:"time"`     // absolute ms
+	Duration float64              `json:"duration"` // ms
+	Text     string               `json:"text"`
+	Syllabus []lyricsPlusSyllable `json:"syllabus"`
+}
+
+type lyricsPlusResponse struct {
+	Type   string           `json:"type"` // "Word" | "Line" | "Syllable" | "None"
+	Lyrics []lyricsPlusLine `json:"lyrics"`
+}
+
+// FetchLyrics tries each LyricsPlus server in order until one returns usable
+// lyrics. multiPersonWordByWord and preserveWordTiming mirror the Apple/QQ
+// options so word/background timing is only emitted when the user enabled it.
+func (c *LyricsPlusClient) FetchLyrics(
+	trackName,
+	artistName,
+	isrc string,
+	durationSec float64,
+	multiPersonWordByWord bool,
+	preserveWordTiming bool,
+) (*LyricsResponse, error) {
+	if strings.TrimSpace(trackName) == "" || strings.TrimSpace(artistName) == "" {
+		return nil, fmt.Errorf("lyricsplus: missing track or artist")
+	}
+
+	var lastErr error
+	for _, server := range lyricsPlusServers {
+		lyrics, err := c.fetchFromServer(server, trackName, artistName, isrc, durationSec, multiPersonWordByWord, preserveWordTiming)
+		if err == nil && lyricsHasUsableText(lyrics) {
+			return lyrics, nil
+		}
+		if err != nil {
+			lastErr = err
+			GoLog("[Lyrics] LyricsPlus server %s failed: %v\n", server, err)
+		}
+	}
+
+	if lastErr != nil {
+		return nil, lastErr
+	}
+	return nil, fmt.Errorf("lyricsplus: no lyrics found")
+}
+
+func (c *LyricsPlusClient) fetchFromServer(
+	server,
+	trackName,
+	artistName,
+	isrc string,
+	durationSec float64,
+	multiPersonWordByWord bool,
+	preserveWordTiming bool,
+) (*LyricsResponse, error) {
+	base := strings.TrimRight(strings.TrimSpace(server), "/")
+	if base == "" {
+		return nil, fmt.Errorf("empty server")
+	}
+
+	params := url.Values{}
+	params.Set("title", trackName)
+	params.Set("artist", artistName)
+	if durationSec > 0 {
+		params.Set("duration", strconv.FormatFloat(durationSec, 'f', 3, 64))
+	}
+	if strings.TrimSpace(isrc) != "" {
+		params.Set("isrc", strings.TrimSpace(isrc))
+	}
+
+	fullURL := base + "/v2/lyrics/get?" + params.Encode()
+
+	req, err := http.NewRequest("GET", fullURL, nil)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create request: %w", err)
+	}
+	req.Header.Set("Accept", "application/json")
+	req.Header.Set("User-Agent", appUserAgent())
+
+	resp, err := c.httpClient.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode == http.StatusNotFound {
+		// Retry without the ISRC filter, which can be too strict.
+		if strings.TrimSpace(isrc) != "" {
+			return c.fetchFromServer(server, trackName, artistName, "", durationSec, multiPersonWordByWord, preserveWordTiming)
+		}
+		return nil, fmt.Errorf("lyrics not found")
+	}
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("HTTP %d", resp.StatusCode)
+	}
+
+	var payload lyricsPlusResponse
+	if err := json.NewDecoder(resp.Body).Decode(&payload); err != nil {
+		return nil, fmt.Errorf("failed to decode lyricsplus response: %w", err)
+	}
+	if len(payload.Lyrics) == 0 {
+		return nil, fmt.Errorf("lyricsplus returned no lines")
+	}
+
+	lrcText := buildLyricsPlusLRC(&payload, multiPersonWordByWord, preserveWordTiming)
+	if strings.TrimSpace(lrcText) == "" {
+		return nil, fmt.Errorf("lyricsplus produced empty lyrics")
+	}
+
+	lyrics := lyricsResponseFromText(lrcText, "LyricsPlus")
+	return lyrics, nil
+}
+
+// buildLyricsPlusLRC converts the KPOE JSON into enhanced LRC text. When word
+// timing is available and enabled, each syllable is emitted as an inline
+// <mm:ss.xx> tag (matching the Apple/QQ output); otherwise a line-synced LRC
+// is produced from the full line text.
+func buildLyricsPlusLRC(resp *lyricsPlusResponse, multiPersonWordByWord bool, preserveWordTiming bool) string {
+	isWordType := strings.EqualFold(resp.Type, "Word") || strings.EqualFold(resp.Type, "Syllable")
+
+	var sb strings.Builder
+	first := true
+	for _, line := range resp.Lyrics {
+		lineText := line.Text
+		hasSyllables := len(line.Syllabus) > 0
+
+		timestamp := msToLRCTimestamp(int64(line.Time))
+
+		if isWordType && preserveWordTiming && hasSyllables {
+			mainSyllables := make([]lyricsPlusSyllable, 0, len(line.Syllabus))
+			bgSyllables := make([]lyricsPlusSyllable, 0)
+			for _, syl := range line.Syllabus {
+				if syl.IsBackground {
+					bgSyllables = append(bgSyllables, syl)
+				} else {
+					mainSyllables = append(mainSyllables, syl)
+				}
+			}
+			if len(mainSyllables) == 0 {
+				mainSyllables = line.Syllabus
+				bgSyllables = nil
+			}
+
+			if !first {
+				sb.WriteString("\n")
+			}
+			first = false
+
+			sb.WriteString(timestamp)
+			appendLyricsPlusSyllables(&sb, mainSyllables)
+
+			if multiPersonWordByWord && len(bgSyllables) > 0 {
+				sb.WriteString("\n[bg:")
+				appendLyricsPlusSyllables(&sb, bgSyllables)
+				sb.WriteString("]")
+			}
+			continue
+		}
+
+		// Line-synced fallback. Reconstruct text from syllables if needed.
+		if strings.TrimSpace(lineText) == "" && hasSyllables {
+			var lineBuilder strings.Builder
+			for _, syl := range line.Syllabus {
+				lineBuilder.WriteString(syl.Text)
+			}
+			lineText = lineBuilder.String()
+		}
+
+		lineText = strings.TrimSpace(lineText)
+		if lineText == "" {
+			continue
+		}
+
+		if !first {
+			sb.WriteString("\n")
+		}
+		first = false
+
+		sb.WriteString(timestamp)
+		sb.WriteString(lineText)
+	}
+
+	return strings.TrimSpace(sb.String())
+}
+
+// appendLyricsPlusSyllables writes each syllable as "<mm:ss.xx>text". KPOE
+// already embeds spacing inside the syllable text, so no extra spaces are added.
+func appendLyricsPlusSyllables(sb *strings.Builder, syllables []lyricsPlusSyllable) {
+	for _, syl := range syllables {
+		sb.WriteString("<")
+		sb.WriteString(msToLRCTimestampInline(int64(syl.Time)))
+		sb.WriteString(">")
+		sb.WriteString(syl.Text)
+	}
+}

go_backend/lyrics_paxsenix.go

@@ -0,0 +1,565 @@
+package gobackend
+
+import (
+	"encoding/json"
+	"fmt"
+	"io"
+	"math"
+	"net/http"
+	"net/url"
+	"regexp"
+	"strconv"
+	"strings"
+	"time"
+)
+
+type SpotifyLyricsClient struct {
+	httpClient *http.Client
+}
+
+type DeezerLyricsClient struct {
+	httpClient *http.Client
+}
+
+type YouTubeLyricsClient struct {
+	httpClient *http.Client
+}
+
+type KugouLyricsClient struct {
+	httpClient *http.Client
+}
+
+type GeniusLyricsClient struct {
+	httpClient *http.Client
+}
+
+type spotifyLyricsSearchResult struct {
+	TrackID    string `json:"trackId"`
+	Name       string `json:"name"`
+	ArtistName string `json:"artistName"`
+	Duration   string `json:"duration"`
+}
+
+type youtubeLyricsSearchResult struct {
+	VideoID  string `json:"videoId"`
+	Title    string `json:"title"`
+	Author   string `json:"author"`
+	Duration string `json:"duration"`
+}
+
+type kugouLyricsSearchResult struct {
+	Hash     string  `json:"hash"`
+	Title    string  `json:"title"`
+	Artist   string  `json:"artist"`
+	Duration float64 `json:"duration"`
+}
+
+type geniusSearchResponse struct {
+	Response struct {
+		Sections []struct {
+			Hits []struct {
+				Type   string `json:"type"`
+				Result struct {
+					Title              string `json:"title"`
+					ArtistNames        string `json:"artist_names"`
+					PrimaryArtistNames string `json:"primary_artist_names"`
+					URL                string `json:"url"`
+				} `json:"result"`
+			} `json:"hits"`
+		} `json:"sections"`
+	} `json:"response"`
+}
+
+type paxsenixLyricsObject struct {
+	Type        string      `json:"type"`
+	Content     []paxLyrics `json:"content"`
+	Lyrics      []paxLyrics `json:"lyrics"`
+	LyricsText  string      `json:"lyrics_text"`
+	PlainLyrics string      `json:"plain_lyrics"`
+}
+
+func NewSpotifyLyricsClient() *SpotifyLyricsClient {
+	return &SpotifyLyricsClient{httpClient: NewMetadataHTTPClient(15 * time.Second)}
+}
+
+func NewDeezerLyricsClient() *DeezerLyricsClient {
+	return &DeezerLyricsClient{httpClient: NewMetadataHTTPClient(15 * time.Second)}
+}
+
+func NewYouTubeLyricsClient() *YouTubeLyricsClient {
+	return &YouTubeLyricsClient{httpClient: NewMetadataHTTPClient(15 * time.Second)}
+}
+
+func NewKugouLyricsClient() *KugouLyricsClient {
+	return &KugouLyricsClient{httpClient: NewMetadataHTTPClient(15 * time.Second)}
+}
+
+func NewGeniusLyricsClient() *GeniusLyricsClient {
+	return &GeniusLyricsClient{httpClient: NewMetadataHTTPClient(15 * time.Second)}
+}
+
+func fetchPaxsenixBody(httpClient *http.Client, endpoint string, params url.Values) (string, error) {
+	fullURL := endpoint
+	if len(params) > 0 {
+		fullURL += "?" + params.Encode()
+	}
+
+	req, err := http.NewRequest("GET", fullURL, nil)
+	if err != nil {
+		return "", fmt.Errorf("failed to create request: %w", err)
+	}
+	req.Header.Set("Accept", "application/json")
+	req.Header.Set("User-Agent", appUserAgent())
+
+	resp, err := httpClient.Do(req)
+	if err != nil {
+		return "", err
+	}
+	defer resp.Body.Close()
+
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return "", fmt.Errorf("failed to read response: %w", err)
+	}
+
+	trimmed := strings.TrimSpace(string(body))
+	if resp.StatusCode != http.StatusOK {
+		if errMsg, isErrorPayload := detectLyricsErrorPayload(trimmed); isErrorPayload {
+			return "", fmt.Errorf("HTTP %d: %s", resp.StatusCode, errMsg)
+		}
+		return "", fmt.Errorf("HTTP %d", resp.StatusCode)
+	}
+	if errMsg, isErrorPayload := detectLyricsErrorPayload(trimmed); isErrorPayload {
+		return "", fmt.Errorf("%s", errMsg)
+	}
+	if trimmed == "" {
+		return "", fmt.Errorf("empty response")
+	}
+	return trimmed, nil
+}
+
+func parsePaxsenixLyricsPayload(raw, provider string, multiPersonWordByWord bool) (*LyricsResponse, error) {
+	var lrcPayload string
+	if err := json.Unmarshal([]byte(raw), &lrcPayload); err == nil {
+		lrcPayload = strings.TrimSpace(lrcPayload)
+		if lrcPayload == "" {
+			return nil, fmt.Errorf("%s returned empty lyrics", provider)
+		}
+		return lyricsResponseFromText(lrcPayload, provider), nil
+	}
+
+	var rawObject map[string]json.RawMessage
+	if err := json.Unmarshal([]byte(raw), &rawObject); err == nil {
+		for _, key := range []string{"lyrics", "lyric", "lyrics_text", "plain_lyrics"} {
+			var value string
+			if rawValue, ok := rawObject[key]; ok && json.Unmarshal(rawValue, &value) == nil {
+				value = strings.TrimSpace(value)
+				if value != "" {
+					return lyricsResponseFromText(value, provider), nil
+				}
+			}
+		}
+	}
+
+	var payload paxsenixLyricsObject
+	if err := json.Unmarshal([]byte(raw), &payload); err == nil {
+		switch {
+		case strings.TrimSpace(payload.LyricsText) != "":
+			return lyricsResponseFromText(payload.LyricsText, provider), nil
+		case len(payload.Lyrics) > 0:
+			return lyricsResponseFromText(formatPaxContent("Syllable", payload.Lyrics, multiPersonWordByWord, true), provider), nil
+		case len(payload.Content) > 0:
+			lyricsType := payload.Type
+			if lyricsType == "" {
+				lyricsType = "Syllable"
+			}
+			return lyricsResponseFromText(formatPaxContent(lyricsType, payload.Content, multiPersonWordByWord, true), provider), nil
+		case strings.TrimSpace(payload.PlainLyrics) != "":
+			return lyricsResponseFromText(payload.PlainLyrics, provider), nil
+		}
+	}
+
+	trimmed := strings.TrimSpace(raw)
+	if trimmed != "" && !strings.HasPrefix(trimmed, "{") && !strings.HasPrefix(trimmed, "[") {
+		return lyricsResponseFromText(trimmed, provider), nil
+	}
+	return nil, fmt.Errorf("failed to decode %s lyrics response", provider)
+}
+
+func lyricsResponseFromText(text, provider string) *LyricsResponse {
+	lines := parseSyncedLyrics(text)
+	if len(lines) > 0 {
+		return &LyricsResponse{
+			Lines:       lines,
+			SyncType:    "LINE_SYNCED",
+			PlainLyrics: plainLyricsFromTimedLines(lines),
+			Provider:    provider,
+			Source:      provider,
+		}
+	}
+
+	plainLines := plainTextLyricsLines(text)
+	if len(plainLines) > 0 {
+		return &LyricsResponse{
+			Lines:       plainLines,
+			SyncType:    "UNSYNCED",
+			PlainLyrics: text,
+			Provider:    provider,
+			Source:      provider,
+		}
+	}
+
+	return &LyricsResponse{Provider: provider, Source: provider}
+}
+
+func normalizeSpotifyLyricsID(raw string) string {
+	raw = strings.TrimSpace(raw)
+	if raw == "" || strings.HasPrefix(strings.ToLower(raw), "deezer:") {
+		return ""
+	}
+	if strings.HasPrefix(strings.ToLower(raw), "spotify:") {
+		parts := strings.Split(raw, ":")
+		raw = parts[len(parts)-1]
+	}
+	if strings.Contains(raw, "spotify.com/track/") {
+		raw = extractSpotifyIDFromURL(raw)
+	}
+	raw = strings.TrimSpace(strings.Split(raw, "?")[0])
+	if regexpSpotifyTrackID.MatchString(raw) {
+		return raw
+	}
+	return ""
+}
+
+var regexpSpotifyTrackID = regexp.MustCompile(`^[A-Za-z0-9]{22}$`)
+
+func (c *SpotifyLyricsClient) SearchSong(trackName, artistName string, durationSec float64) (string, error) {
+	query := strings.TrimSpace(trackName + " " + artistName)
+	if query == "" {
+		return "", fmt.Errorf("empty search query")
+	}
+
+	params := url.Values{}
+	params.Set("q", query)
+	raw, err := fetchPaxsenixBody(c.httpClient, "https://lyrics.paxsenix.org/spotify/search", params)
+	if err != nil {
+		return "", fmt.Errorf("spotify search failed: %w", err)
+	}
+
+	var results []spotifyLyricsSearchResult
+	if err := json.Unmarshal([]byte(raw), &results); err != nil {
+		return "", fmt.Errorf("failed to decode spotify search: %w", err)
+	}
+	best := selectBestSpotifyLyricsSearchResult(results, trackName, artistName, durationSec)
+	if best == nil || strings.TrimSpace(best.TrackID) == "" {
+		return "", fmt.Errorf("no songs found on spotify")
+	}
+	return strings.TrimSpace(best.TrackID), nil
+}
+
+func selectBestSpotifyLyricsSearchResult(results []spotifyLyricsSearchResult, trackName, artistName string, durationSec float64) *spotifyLyricsSearchResult {
+	if len(results) == 0 {
+		return nil
+	}
+
+	bestIndex := 0
+	bestScore := -1
+	for i := range results {
+		result := &results[i]
+		score := scoreLyricsSearchCandidate(result.Name, result.ArtistName, parseClockDuration(result.Duration), trackName, artistName, durationSec)
+		if score > bestScore {
+			bestIndex = i
+			bestScore = score
+		}
+	}
+	return &results[bestIndex]
+}
+
+func (c *SpotifyLyricsClient) FetchLyricsByID(trackID string) (*LyricsResponse, error) {
+	params := url.Values{}
+	params.Set("id", trackID)
+	raw, err := fetchPaxsenixBody(c.httpClient, "https://lyrics.paxsenix.org/spotify/lyrics", params)
+	if err != nil {
+		return nil, fmt.Errorf("spotify lyrics fetch failed: %w", err)
+	}
+	return parsePaxsenixLyricsPayload(raw, "Spotify", false)
+}
+
+func (c *SpotifyLyricsClient) FetchLyrics(spotifyID, trackName, artistName string, durationSec float64) (*LyricsResponse, error) {
+	trackID := normalizeSpotifyLyricsID(spotifyID)
+	if trackID == "" {
+		var err error
+		trackID, err = c.SearchSong(trackName, artistName, durationSec)
+		if err != nil {
+			return nil, err
+		}
+	}
+	return c.FetchLyricsByID(trackID)
+}
+
+func normalizeDeezerLyricsID(raw string) string {
+	raw = strings.TrimSpace(raw)
+	if strings.HasPrefix(strings.ToLower(raw), "deezer:") {
+		raw = strings.TrimSpace(raw[len("deezer:"):])
+	}
+	if strings.Contains(raw, "deezer.com/") {
+		raw = extractDeezerIDFromURL(raw)
+	}
+	raw = strings.TrimSpace(strings.Split(raw, "?")[0])
+	if _, err := strconv.ParseInt(raw, 10, 64); err == nil {
+		return raw
+	}
+	return ""
+}
+
+func (c *DeezerLyricsClient) FetchLyricsByID(trackID string, multiPersonWordByWord bool) (*LyricsResponse, error) {
+	params := url.Values{}
+	params.Set("id", trackID)
+	raw, err := fetchPaxsenixBody(c.httpClient, "https://lyrics.paxsenix.org/deezer/lyrics", params)
+	if err != nil {
+		return nil, fmt.Errorf("deezer lyrics fetch failed: %w", err)
+	}
+	return parsePaxsenixLyricsPayload(raw, "Deezer", multiPersonWordByWord)
+}
+
+func (c *DeezerLyricsClient) FetchLyrics(spotifyID, trackName, artistName string, durationSec float64) (*LyricsResponse, error) {
+	deezerID := normalizeDeezerLyricsID(spotifyID)
+	if deezerID == "" {
+		spotifyTrackID := normalizeSpotifyLyricsID(spotifyID)
+		if spotifyTrackID == "" {
+			return nil, fmt.Errorf("deezer provider needs a deezer id or spotify id")
+		}
+		resolvedID, err := NewSongLinkClient().GetDeezerIDFromSpotify(spotifyTrackID)
+		if err != nil {
+			return nil, fmt.Errorf("failed to resolve deezer id: %w", err)
+		}
+		deezerID = normalizeDeezerLyricsID(resolvedID)
+	}
+	if deezerID == "" {
+		return nil, fmt.Errorf("deezer id unavailable")
+	}
+	return c.FetchLyricsByID(deezerID, true)
+}
+
+func (c *YouTubeLyricsClient) SearchSong(trackName, artistName string, durationSec float64) (string, error) {
+	query := strings.TrimSpace(trackName + " " + artistName)
+	if query == "" {
+		return "", fmt.Errorf("empty search query")
+	}
+
+	params := url.Values{}
+	params.Set("q", query)
+	raw, err := fetchPaxsenixBody(c.httpClient, "https://lyrics.paxsenix.org/youtube/search", params)
+	if err != nil {
+		return "", fmt.Errorf("youtube search failed: %w", err)
+	}
+
+	var results []youtubeLyricsSearchResult
+	if err := json.Unmarshal([]byte(raw), &results); err != nil {
+		return "", fmt.Errorf("failed to decode youtube search: %w", err)
+	}
+	best := selectBestYouTubeLyricsSearchResult(results, trackName, artistName, durationSec)
+	if best == nil || strings.TrimSpace(best.VideoID) == "" {
+		return "", fmt.Errorf("no songs found on youtube")
+	}
+	return strings.TrimSpace(best.VideoID), nil
+}
+
+func selectBestYouTubeLyricsSearchResult(results []youtubeLyricsSearchResult, trackName, artistName string, durationSec float64) *youtubeLyricsSearchResult {
+	if len(results) == 0 {
+		return nil
+	}
+
+	bestIndex := 0
+	bestScore := -1
+	for i := range results {
+		result := &results[i]
+		score := scoreLyricsSearchCandidate(result.Title, result.Author, parseClockDuration(result.Duration), trackName, artistName, durationSec)
+		if score > bestScore {
+			bestIndex = i
+			bestScore = score
+		}
+	}
+	return &results[bestIndex]
+}
+
+func (c *YouTubeLyricsClient) FetchLyrics(trackName, artistName string, durationSec float64) (*LyricsResponse, error) {
+	videoID, err := c.SearchSong(trackName, artistName, durationSec)
+	if err != nil {
+		return nil, err
+	}
+
+	params := url.Values{}
+	params.Set("id", videoID)
+	raw, err := fetchPaxsenixBody(c.httpClient, "https://lyrics.paxsenix.org/youtube/lyrics", params)
+	if err != nil {
+		return nil, fmt.Errorf("youtube lyrics fetch failed: %w", err)
+	}
+	return parsePaxsenixLyricsPayload(raw, "YouTube", false)
+}
+
+func (c *KugouLyricsClient) SearchSong(trackName, artistName string, durationSec float64) (string, error) {
+	query := strings.TrimSpace(trackName + " " + artistName)
+	if query == "" {
+		return "", fmt.Errorf("empty search query")
+	}
+
+	params := url.Values{}
+	params.Set("q", query)
+	raw, err := fetchPaxsenixBody(c.httpClient, "https://lyrics.paxsenix.org/kugou/search", params)
+	if err != nil {
+		return "", fmt.Errorf("kugou search failed: %w", err)
+	}
+
+	var results []kugouLyricsSearchResult
+	if err := json.Unmarshal([]byte(raw), &results); err != nil {
+		return "", fmt.Errorf("failed to decode kugou search: %w", err)
+	}
+	best := selectBestKugouLyricsSearchResult(results, trackName, artistName, durationSec)
+	if best == nil || strings.TrimSpace(best.Hash) == "" {
+		return "", fmt.Errorf("no songs found on kugou")
+	}
+	return strings.TrimSpace(best.Hash), nil
+}
+
+func selectBestKugouLyricsSearchResult(results []kugouLyricsSearchResult, trackName, artistName string, durationSec float64) *kugouLyricsSearchResult {
+	if len(results) == 0 {
+		return nil
+	}
+
+	bestIndex := 0
+	bestScore := -1
+	for i := range results {
+		result := &results[i]
+		score := scoreLyricsSearchCandidate(result.Title, result.Artist, result.Duration, trackName, artistName, durationSec)
+		if score > bestScore {
+			bestIndex = i
+			bestScore = score
+		}
+	}
+	return &results[bestIndex]
+}
+
+func (c *KugouLyricsClient) FetchLyrics(trackName, artistName string, durationSec float64) (*LyricsResponse, error) {
+	hash, err := c.SearchSong(trackName, artistName, durationSec)
+	if err != nil {
+		return nil, err
+	}
+
+	params := url.Values{}
+	params.Set("id", hash)
+	raw, err := fetchPaxsenixBody(c.httpClient, "https://lyrics.paxsenix.org/kugou/lyrics", params)
+	if err != nil {
+		return nil, fmt.Errorf("kugou lyrics fetch failed: %w", err)
+	}
+	return parsePaxsenixLyricsPayload(raw, "Kugou", false)
+}
+
+func (c *GeniusLyricsClient) SearchSong(trackName, artistName string, durationSec float64) (string, error) {
+	query := strings.TrimSpace(trackName + " " + artistName)
+	if query == "" {
+		return "", fmt.Errorf("empty search query")
+	}
+
+	params := url.Values{}
+	params.Set("q", query)
+	params.Set("per_page", "10")
+	raw, err := fetchPaxsenixBody(c.httpClient, "https://genius.com/api/search/multi", params)
+	if err != nil {
+		return "", fmt.Errorf("genius search failed: %w", err)
+	}
+
+	var results geniusSearchResponse
+	if err := json.Unmarshal([]byte(raw), &results); err != nil {
+		return "", fmt.Errorf("failed to decode genius search: %w", err)
+	}
+
+	bestURL := ""
+	bestScore := -1
+	for _, section := range results.Response.Sections {
+		for _, hit := range section.Hits {
+			if hit.Type != "song" || strings.TrimSpace(hit.Result.URL) == "" {
+				continue
+			}
+
+			artist := hit.Result.PrimaryArtistNames
+			if strings.TrimSpace(artist) == "" {
+				artist = hit.Result.ArtistNames
+			}
+			score := scoreLyricsSearchCandidate(hit.Result.Title, artist, 0, trackName, artistName, durationSec)
+			if score > bestScore {
+				bestScore = score
+				bestURL = strings.TrimSpace(hit.Result.URL)
+			}
+		}
+	}
+
+	if bestURL == "" {
+		return "", fmt.Errorf("no songs found on genius")
+	}
+	return bestURL, nil
+}
+
+func (c *GeniusLyricsClient) FetchLyrics(trackName, artistName string, durationSec float64) (*LyricsResponse, error) {
+	geniusURL, err := c.SearchSong(trackName, artistName, durationSec)
+	if err != nil {
+		return nil, err
+	}
+
+	params := url.Values{}
+	params.Set("url", geniusURL)
+	raw, err := fetchPaxsenixBody(c.httpClient, "https://lyrics.paxsenix.org/genius/lyrics", params)
+	if err != nil {
+		return nil, fmt.Errorf("genius lyrics fetch failed: %w", err)
+	}
+	return parsePaxsenixLyricsPayload(raw, "Genius", false)
+}
+
+func scoreLyricsSearchCandidate(candidateTrack, candidateArtist string, candidateDuration float64, trackName, artistName string, durationSec float64) int {
+	normalizedTrack := strings.ToLower(strings.TrimSpace(simplifyTrackName(trackName)))
+	normalizedArtist := strings.ToLower(strings.TrimSpace(normalizeArtistName(artistName)))
+	candidateTrack = strings.ToLower(strings.TrimSpace(simplifyTrackName(candidateTrack)))
+	candidateArtist = strings.ToLower(strings.TrimSpace(normalizeArtistName(candidateArtist)))
+
+	score := 0
+	switch {
+	case candidateTrack == normalizedTrack:
+		score += 50
+	case strings.Contains(candidateTrack, normalizedTrack) || strings.Contains(normalizedTrack, candidateTrack):
+		score += 25
+	}
+
+	switch {
+	case candidateArtist == normalizedArtist:
+		score += 60
+	case strings.Contains(candidateArtist, normalizedArtist) || strings.Contains(normalizedArtist, candidateArtist):
+		score += 30
+	}
+
+	if durationSec > 0 && candidateDuration > 0 {
+		diff := math.Abs(candidateDuration - durationSec)
+		if diff <= durationToleranceSec {
+			score += 20
+		}
+	}
+
+	return score
+}
+
+func parseClockDuration(value string) float64 {
+	value = strings.TrimSpace(value)
+	if value == "" {
+		return 0
+	}
+
+	parts := strings.Split(value, ":")
+	total := 0
+	for _, part := range parts {
+		n, err := strconv.Atoi(strings.TrimSpace(part))
+		if err != nil {
+			return 0
+		}
+		total = total*60 + n
+	}
+	return float64(total)
+}

go_backend/lyrics_qqmusic.go

@@ -87,7 +87,7 @@ func formatQQLyricsMetadataToLRC(rawJSON string, multiPersonWordByWord bool) (st
 	if len(response.Lyrics) == 0 {
 		return "", fmt.Errorf("qq metadata lyrics response was empty")
 	}
-	return formatPaxContent("Syllable", response.Lyrics, multiPersonWordByWord), nil
+	return formatPaxContent("Syllable", response.Lyrics, multiPersonWordByWord, true), nil
 }
 
 func (c *QQMusicClient) FetchLyrics(
@@ -106,7 +106,7 @@ func (c *QQMusicClient) FetchLyrics(
 
 	lrcText, err := formatQQLyricsMetadataToLRC(rawLyrics, multiPersonWordByWord)
 	if err != nil {
-		if fallback, fallbackErr := formatPaxLyricsToLRC(rawLyrics, multiPersonWordByWord); fallbackErr == nil {
+		if fallback, fallbackErr := formatPaxLyricsToLRC(rawLyrics, multiPersonWordByWord, true); fallbackErr == nil {
 			lrcText = fallback
 		} else {
 			lrcText = rawLyrics

go_backend/lyrics_supplement_test.go

@@ -131,14 +131,18 @@ func TestLyricsCacheParsingAndLRCLibClient(t *testing.T) {
 }
 
 func TestExternalLyricsProvidersWithFakeHTTP(t *testing.T) {
+	clearAppleMusicToken()
+	defer clearAppleMusicToken()
+
 	paxJSON := `{"type":"Syllable","content":[{"timestamp":1000,"oppositeTurn":true,"background":true,"text":[{"text":"Hel","part":true,"timestamp":1000},{"text":"lo","part":false,"timestamp":1200,"endtime":1500}],"backgroundText":[{"text":"bg","part":false,"timestamp":900}]}]}`
 	apple := &AppleMusicClient{httpClient: &http.Client{Transport: roundTripFunc(func(req *http.Request) (*http.Response, error) {
 		switch {
-		case strings.Contains(req.URL.Path, "/apple-music/search"):
-			if req.URL.Query().Get("q") == "bad" {
-				return &http.Response{StatusCode: 500, Header: make(http.Header), Body: io.NopCloser(strings.NewReader(`error`)), Request: req}, nil
-			}
-			return &http.Response{StatusCode: 200, Header: make(http.Header), Body: io.NopCloser(strings.NewReader(`[{"id":"apple-2","songName":"Other","artistName":"Other","duration":1000},{"id":"apple-1","songName":"Song","artistName":"Artist","albumName":"Album","duration":180000}]`)), Request: req}, nil
+		case req.URL.Host == "beta.music.apple.com" && (req.URL.Path == "" || req.URL.Path == "/"):
+			return &http.Response{StatusCode: 200, Header: make(http.Header), Body: io.NopCloser(strings.NewReader(`<script src="/assets/index~test.js"></script>`)), Request: req}, nil
+		case req.URL.Host == "beta.music.apple.com" && req.URL.Path == "/assets/index~test.js":
+			return &http.Response{StatusCode: 200, Header: make(http.Header), Body: io.NopCloser(strings.NewReader(`const token="eyJhbGci.test";`)), Request: req}, nil
+		case req.URL.Host == "amp-api.music.apple.com" && strings.Contains(req.URL.Path, "/v1/catalog/us/search"):
+			return &http.Response{StatusCode: 200, Header: make(http.Header), Body: io.NopCloser(strings.NewReader(`{"results":{"songs":{"data":[{"id":"apple-2"},{"id":"apple-1"}]}},"resources":{"songs":{"apple-2":{"attributes":{"name":"Other","artistName":"Other","durationInMillis":1000}},"apple-1":{"attributes":{"name":"Song","artistName":"Artist","albumName":"Album","durationInMillis":180000}}}}}`)), Request: req}, nil
 		case strings.Contains(req.URL.Path, "/apple-music/lyrics"):
 			return &http.Response{StatusCode: 200, Header: make(http.Header), Body: io.NopCloser(strings.NewReader(paxJSON)), Request: req}, nil
 		default:
@@ -156,13 +160,30 @@ func TestExternalLyricsProvidersWithFakeHTTP(t *testing.T) {
 	if err != nil || !strings.Contains(rawApple, "Syllable") {
 		t.Fatalf("apple raw = %q/%v", rawApple, err)
 	}
-	appleLyrics, err := apple.FetchLyrics("Song", "Artist", 180, true)
+	appleLyrics, err := apple.FetchLyrics("Song", "Artist", 180, true, true)
 	if err != nil || appleLyrics.SyncType != "LINE_SYNCED" || appleLyrics.Provider != "Apple Music" {
 		t.Fatalf("apple lyrics = %#v/%v", appleLyrics, err)
 	}
-	if plain, err := formatPaxLyricsToLRC(`[{"timestamp":2000,"text":[{"text":"Plain","part":false}]}]`, false); err != nil || !strings.Contains(plain, "Plain") {
+	if plain, err := formatPaxLyricsToLRC(`[{"timestamp":2000,"text":[{"text":"Plain","part":false}]}]`, false, false); err != nil || !strings.Contains(plain, "Plain") {
 		t.Fatalf("direct pax = %q/%v", plain, err)
 	}
+	lineOnly, err := formatPaxLyricsToLRC(paxJSON, true, false)
+	if err != nil {
+		t.Fatalf("line-only pax = %v", err)
+	}
+	if strings.Contains(lineOnly, "<00:") {
+		t.Fatalf("line-only pax should not include inline word timing: %q", lineOnly)
+	}
+	elrc, err := formatPaxLyricsToLRC(paxJSON, true, true)
+	if err != nil {
+		t.Fatalf("elrc pax = %v", err)
+	}
+	if !strings.Contains(elrc, "<00:") {
+		t.Fatalf("elrc pax should include inline word timing: %q", elrc)
+	}
+	if preferred, err := formatPaxLyricsToLRC(`{"elrcMultiPerson":"[00:01.00]v1:<00:01.00>Hello","content":[{"timestamp":1000,"text":[{"text":"Fallback","part":false}]}]}`, true, true); err != nil || !strings.Contains(preferred, "Hello") {
+		t.Fatalf("preferred apple elrc = %q/%v", preferred, err)
+	}
 	if _, err := apple.SearchSong("", "", 0); err == nil {
 		t.Fatal("expected empty apple search error")
 	}
@@ -233,4 +254,72 @@ func TestExternalLyricsProvidersWithFakeHTTP(t *testing.T) {
 	if _, err := formatQQLyricsMetadataToLRC(`{"lyrics":[]}`, false); err == nil {
 		t.Fatal("expected empty QQ metadata error")
 	}
+
+	spotify := &SpotifyLyricsClient{httpClient: &http.Client{Transport: roundTripFunc(func(req *http.Request) (*http.Response, error) {
+		switch {
+		case strings.Contains(req.URL.Path, "/spotify/search"):
+			return &http.Response{StatusCode: 200, Header: make(http.Header), Body: io.NopCloser(strings.NewReader(`[{"trackId":"spotify-1","name":"Song","artistName":"Artist","duration":"03:00"}]`)), Request: req}, nil
+		case strings.Contains(req.URL.Path, "/spotify/lyrics"):
+			return &http.Response{StatusCode: 200, Header: make(http.Header), Body: io.NopCloser(strings.NewReader(`"[00:01.00]Spotify"`)), Request: req}, nil
+		default:
+			return &http.Response{StatusCode: 404, Header: make(http.Header), Body: io.NopCloser(strings.NewReader(`{}`)), Request: req}, nil
+		}
+	})}}
+	spotifyLyrics, err := spotify.FetchLyrics("", "Song", "Artist", 180)
+	if err != nil || spotifyLyrics.Provider != "Spotify" || spotifyLyrics.SyncType != "LINE_SYNCED" {
+		t.Fatalf("spotify lyrics = %#v/%v", spotifyLyrics, err)
+	}
+
+	deezer := &DeezerLyricsClient{httpClient: &http.Client{Transport: roundTripFunc(func(req *http.Request) (*http.Response, error) {
+		return &http.Response{StatusCode: 200, Header: make(http.Header), Body: io.NopCloser(strings.NewReader(`{"lyrics":[{"timestamp":1000,"text":[{"text":"Deezer","part":false}]}]}`)), Request: req}, nil
+	})}}
+	deezerLyrics, err := deezer.FetchLyricsByID("123", false)
+	if err != nil || deezerLyrics.Provider != "Deezer" || deezerLyrics.SyncType != "LINE_SYNCED" {
+		t.Fatalf("deezer lyrics = %#v/%v", deezerLyrics, err)
+	}
+
+	youtube := &YouTubeLyricsClient{httpClient: &http.Client{Transport: roundTripFunc(func(req *http.Request) (*http.Response, error) {
+		switch {
+		case strings.Contains(req.URL.Path, "/youtube/search"):
+			return &http.Response{StatusCode: 200, Header: make(http.Header), Body: io.NopCloser(strings.NewReader(`[{"videoId":"yt-1","title":"Song","author":"Artist","duration":"3:00"}]`)), Request: req}, nil
+		case strings.Contains(req.URL.Path, "/youtube/lyrics"):
+			return &http.Response{StatusCode: 200, Header: make(http.Header), Body: io.NopCloser(strings.NewReader(`"[00:01.00]YouTube"`)), Request: req}, nil
+		default:
+			return &http.Response{StatusCode: 404, Header: make(http.Header), Body: io.NopCloser(strings.NewReader(`{}`)), Request: req}, nil
+		}
+	})}}
+	youtubeLyrics, err := youtube.FetchLyrics("Song", "Artist", 180)
+	if err != nil || youtubeLyrics.Provider != "YouTube" || youtubeLyrics.SyncType != "LINE_SYNCED" {
+		t.Fatalf("youtube lyrics = %#v/%v", youtubeLyrics, err)
+	}
+
+	kugou := &KugouLyricsClient{httpClient: &http.Client{Transport: roundTripFunc(func(req *http.Request) (*http.Response, error) {
+		switch {
+		case strings.Contains(req.URL.Path, "/kugou/search"):
+			return &http.Response{StatusCode: 200, Header: make(http.Header), Body: io.NopCloser(strings.NewReader(`[{"hash":"kg-1","title":"Song","artist":"Artist","duration":180}]`)), Request: req}, nil
+		case strings.Contains(req.URL.Path, "/kugou/lyrics"):
+			return &http.Response{StatusCode: 200, Header: make(http.Header), Body: io.NopCloser(strings.NewReader(`{"lyrics_text":"[00:01.00]Kugou"}`)), Request: req}, nil
+		default:
+			return &http.Response{StatusCode: 404, Header: make(http.Header), Body: io.NopCloser(strings.NewReader(`{}`)), Request: req}, nil
+		}
+	})}}
+	kugouLyrics, err := kugou.FetchLyrics("Song", "Artist", 180)
+	if err != nil || kugouLyrics.Provider != "Kugou" || kugouLyrics.SyncType != "LINE_SYNCED" {
+		t.Fatalf("kugou lyrics = %#v/%v", kugouLyrics, err)
+	}
+
+	genius := &GeniusLyricsClient{httpClient: &http.Client{Transport: roundTripFunc(func(req *http.Request) (*http.Response, error) {
+		switch {
+		case strings.Contains(req.URL.Path, "/api/search/multi"):
+			return &http.Response{StatusCode: 200, Header: make(http.Header), Body: io.NopCloser(strings.NewReader(`{"response":{"sections":[{"hits":[{"type":"song","result":{"title":"Song","primary_artist_names":"Artist","url":"https://genius.com/artist-song-lyrics"}}]}]}}`)), Request: req}, nil
+		case strings.Contains(req.URL.Path, "/genius/lyrics"):
+			return &http.Response{StatusCode: 200, Header: make(http.Header), Body: io.NopCloser(strings.NewReader(`{"error":false,"lyrics":"Genius line"}`)), Request: req}, nil
+		default:
+			return &http.Response{StatusCode: 404, Header: make(http.Header), Body: io.NopCloser(strings.NewReader(`{}`)), Request: req}, nil
+		}
+	})}}
+	geniusLyrics, err := genius.FetchLyrics("Song", "Artist", 180)
+	if err != nil || geniusLyrics.Provider != "Genius" || geniusLyrics.SyncType != "UNSYNCED" {
+		t.Fatalf("genius lyrics = %#v/%v", geniusLyrics, err)
+	}
 }

go_backend/metadata.go

@@ -872,7 +872,7 @@ func ExtractLyrics(filePath string) (string, error) {
 		return extractLyricsFromSidecarLRC(filePath)
 	}
 
-	if strings.HasSuffix(lower, ".m4a") || strings.HasSuffix(lower, ".aac") {
+	if strings.HasSuffix(lower, ".m4a") || strings.HasSuffix(lower, ".mp4") || strings.HasSuffix(lower, ".aac") {
 		lyrics, err := extractLyricsFromM4A(filePath)
 		if err == nil && strings.TrimSpace(lyrics) != "" {
 			return lyrics, nil
@@ -906,6 +906,32 @@ func ExtractLyrics(filePath string) (string, error) {
 		return extractLyricsFromSidecarLRC(filePath)
 	}
 
+	if strings.HasSuffix(lower, ".wav") {
+		meta, err := ReadWAVTags(filePath)
+		if err == nil && meta != nil {
+			if strings.TrimSpace(meta.Lyrics) != "" {
+				return meta.Lyrics, nil
+			}
+			if looksLikeEmbeddedLyrics(meta.Comment) {
+				return meta.Comment, nil
+			}
+		}
+		return extractLyricsFromSidecarLRC(filePath)
+	}
+
+	if strings.HasSuffix(lower, ".aiff") || strings.HasSuffix(lower, ".aif") || strings.HasSuffix(lower, ".aifc") {
+		meta, err := ReadAIFFTags(filePath)
+		if err == nil && meta != nil {
+			if strings.TrimSpace(meta.Lyrics) != "" {
+				return meta.Lyrics, nil
+			}
+			if looksLikeEmbeddedLyrics(meta.Comment) {
+				return meta.Comment, nil
+			}
+		}
+		return extractLyricsFromSidecarLRC(filePath)
+	}
+
 	return extractLyricsFromSidecarLRC(filePath)
 }
 
@@ -1578,10 +1604,12 @@ func looksLikeEmbeddedLyrics(value string) bool {
 }
 
 type AudioQuality struct {
-	BitDepth     int   `json:"bit_depth"`
-	SampleRate   int   `json:"sample_rate"`
-	TotalSamples int64 `json:"total_samples"`
-	Duration     int   `json:"duration"`
+	BitDepth     int    `json:"bit_depth"`
+	SampleRate   int    `json:"sample_rate"`
+	TotalSamples int64  `json:"total_samples"`
+	Duration     int    `json:"duration"`
+	Bitrate      int    `json:"bitrate,omitempty"` // kbps, estimated for compressed MP4-family streams
+	Codec        string `json:"codec,omitempty"`
 }
 
 func GetAudioQuality(filePath string) (AudioQuality, error) {
@@ -1632,6 +1660,7 @@ func GetAudioQuality(filePath string) (AudioQuality, error) {
 			SampleRate:   sampleRate,
 			TotalSamples: totalSamples,
 			Duration:     duration,
+			Codec:        "flac",
 		}, nil
 	}
 
@@ -1695,9 +1724,11 @@ func GetM4AQuality(filePath string) (AudioQuality, error) {
 	//   [26:28] reserved
 	//   [28:32] samplerate (16.16 fixed-point)
 	sampleRate := int(buf[28])<<8 | int(buf[29])
-	bitDepth := int(buf[22])<<8 | int(buf[23])
+	bitDepth := 0
+	codec := normalizeM4AAudioCodec(atomType)
 
 	if atomType == "alac" {
+		bitDepth = int(buf[22])<<8 | int(buf[23])
 		if alacBitDepth, alacSampleRate, ok := readALACSpecificConfig(f, sampleOffset, fileSize); ok {
 			if alacBitDepth > 0 {
 				bitDepth = alacBitDepth
@@ -1706,24 +1737,75 @@ func GetM4AQuality(filePath string) (AudioQuality, error) {
 				sampleRate = alacSampleRate
 			}
 		}
+	} else if atomType == "fLaC" {
+		bitDepth = int(buf[22])<<8 | int(buf[23])
+		if flacBitDepth, flacSampleRate, flacTotalSamples, ok := readMP4FLACSpecificConfig(f, sampleOffset, fileSize); ok {
+			if flacBitDepth > 0 {
+				bitDepth = flacBitDepth
+			}
+			if flacSampleRate > 0 {
+				sampleRate = flacSampleRate
+			}
+			if flacTotalSamples > 0 && sampleRate > 0 && duration <= 0 {
+				duration = int(flacTotalSamples / int64(sampleRate))
+			}
+		}
 	}
 
-	if bitDepth <= 0 {
-		bitDepth = 16
+	bitrate := estimateAudioBitrateKbps(fileSize, duration)
+	if bitrate > 0 && bitrate < 16 {
+		bitrate = 0
 	}
+	return AudioQuality{
+		BitDepth:   bitDepth,
+		SampleRate: sampleRate,
+		Duration:   duration,
+		Bitrate:    bitrate,
+		Codec:      codec,
+	}, nil
+}
 
-	return AudioQuality{BitDepth: bitDepth, SampleRate: sampleRate, Duration: duration}, nil
+func normalizeM4AAudioCodec(atomType string) string {
+	switch atomType {
+	case "mp4a":
+		return "aac"
+	case "alac":
+		return "alac"
+	case "fLaC":
+		return "flac"
+	case "ec-3":
+		return "eac3"
+	case "ac-3":
+		return "ac3"
+	case "ac-4":
+		return "ac4"
+	default:
+		return strings.TrimSpace(atomType)
+	}
+}
+
+func estimateAudioBitrateKbps(fileSize int64, durationSeconds int) int {
+	if fileSize <= 0 || durationSeconds <= 0 {
+		return 0
+	}
+	return int(math.Round(float64(fileSize*8) / float64(durationSeconds) / 1000.0))
 }
 
 func readM4ADurationSeconds(f *os.File, moovHeader atomHeader, fileSize int64) int {
 	childStart := moovHeader.offset + moovHeader.headerSize
 	childSize := moovHeader.size - moovHeader.headerSize
 	mvhdHeader, found, err := findAtomInRange(f, childStart, childSize, "mvhd", fileSize)
-	if err != nil || !found {
-		return 0
+	if err == nil && found {
+		if duration := readMP4DurationAtomSeconds(f, mvhdHeader, fileSize); duration > 0 {
+			return duration
+		}
 	}
 
-	payloadOffset := mvhdHeader.offset + mvhdHeader.headerSize
+	return readM4ATrackDurationSeconds(f, moovHeader, fileSize)
+}
+
+func readMP4DurationAtomSeconds(f *os.File, header atomHeader, fileSize int64) int {
+	payloadOffset := header.offset + header.headerSize
 	versionBuf := make([]byte, 1)
 	if _, err := f.ReadAt(versionBuf, payloadOffset); err != nil {
 		return 0
@@ -1754,6 +1836,53 @@ func readM4ADurationSeconds(f *os.File, moovHeader atomHeader, fileSize int64) i
 	return int(math.Round(float64(duration) / float64(timescale)))
 }
 
+func readM4ATrackDurationSeconds(f *os.File, moovHeader atomHeader, fileSize int64) int {
+	childStart := moovHeader.offset + moovHeader.headerSize
+	childSize := moovHeader.size - moovHeader.headerSize
+	bestDuration := 0
+	_ = walkMP4AtomsInRange(f, childStart, childSize, fileSize, func(header atomHeader) bool {
+		if header.typ == "mdhd" {
+			if duration := readMP4DurationAtomSeconds(f, header, fileSize); duration > bestDuration {
+				bestDuration = duration
+			}
+			return false
+		}
+		return header.typ == "trak" || header.typ == "mdia"
+	})
+	return bestDuration
+}
+
+func walkMP4AtomsInRange(f *os.File, start, size, fileSize int64, visit func(atomHeader) bool) error {
+	if size <= 0 {
+		return nil
+	}
+
+	end := start + size
+	for pos := start; pos+8 <= end; {
+		header, err := readAtomHeaderAt(f, pos, fileSize)
+		if err != nil {
+			return err
+		}
+		atomSize := header.size
+		if atomSize == 0 {
+			atomSize = end - pos
+		}
+		if atomSize < header.headerSize {
+			return fmt.Errorf("invalid atom size for %s", header.typ)
+		}
+		header.size = atomSize
+		if visit(header) {
+			childStart := header.offset + header.headerSize
+			childSize := header.size - header.headerSize
+			if err := walkMP4AtomsInRange(f, childStart, childSize, fileSize, visit); err != nil {
+				return err
+			}
+		}
+		pos += atomSize
+	}
+	return nil
+}
+
 func readALACSpecificConfig(f *os.File, sampleOffset, fileSize int64) (int, int, bool) {
 	if sampleOffset < 4 {
 		return 0, 0, false
@@ -1788,6 +1917,79 @@ func readALACSpecificConfig(f *os.File, sampleOffset, fileSize int64) (int, int,
 	return parseALACSpecificConfig(payload)
 }
 
+func readMP4FLACSpecificConfig(f *os.File, sampleOffset, fileSize int64) (int, int, int64, bool) {
+	if sampleOffset < 4 {
+		return 0, 0, 0, false
+	}
+
+	sampleEntryHeader, err := readAtomHeaderAt(f, sampleOffset-4, fileSize)
+	if err != nil {
+		return 0, 0, 0, false
+	}
+
+	childStart := sampleOffset + 32
+	childEnd := sampleEntryHeader.offset + sampleEntryHeader.size
+	if childStart >= childEnd {
+		return 0, 0, 0, false
+	}
+
+	configHeader, found, err := findAtomInRange(f, childStart, childEnd-childStart, "dfLa", fileSize)
+	if err != nil || !found {
+		return 0, 0, 0, false
+	}
+
+	payloadSize := configHeader.size - configHeader.headerSize
+	if payloadSize <= 0 {
+		return 0, 0, 0, false
+	}
+
+	payload := make([]byte, payloadSize)
+	if _, err := f.ReadAt(payload, configHeader.offset+configHeader.headerSize); err != nil {
+		return 0, 0, 0, false
+	}
+
+	return parseMP4FLACSpecificConfig(payload)
+}
+
+func parseMP4FLACSpecificConfig(payload []byte) (int, int, int64, bool) {
+	if len(payload) >= 4 && string(payload[:4]) == "fLaC" {
+		payload = payload[4:]
+	} else if len(payload) >= 4 {
+		// FLACSpecificBox starts with a full-box version/flags field.
+		payload = payload[4:]
+	}
+
+	for len(payload) >= 4 {
+		blockType := payload[0] & 0x7F
+		blockLen := int(payload[1])<<16 | int(payload[2])<<8 | int(payload[3])
+		if blockLen < 0 || len(payload) < 4+blockLen {
+			return 0, 0, 0, false
+		}
+		block := payload[4 : 4+blockLen]
+		if blockType == 0 && len(block) >= 34 {
+			bitDepth, sampleRate, totalSamples := parseFLACStreamInfoQuality(block[:34])
+			return bitDepth, sampleRate, totalSamples, bitDepth > 0 || sampleRate > 0
+		}
+		payload = payload[4+blockLen:]
+	}
+
+	return 0, 0, 0, false
+}
+
+func parseFLACStreamInfoQuality(streamInfo []byte) (int, int, int64) {
+	if len(streamInfo) < 18 {
+		return 0, 0, 0
+	}
+	sampleRate := (int(streamInfo[10]) << 12) | (int(streamInfo[11]) << 4) | (int(streamInfo[12]) >> 4)
+	bitsPerSample := (((int(streamInfo[12]) & 0x01) << 4) | (int(streamInfo[13]) >> 4)) + 1
+	totalSamples := int64(streamInfo[13]&0x0F)<<32 |
+		int64(streamInfo[14])<<24 |
+		int64(streamInfo[15])<<16 |
+		int64(streamInfo[16])<<8 |
+		int64(streamInfo[17])
+	return bitsPerSample, sampleRate, totalSamples
+}
+
 func parseALACSpecificConfig(payload []byte) (int, int, bool) {
 	if len(payload) < 24 {
 		return 0, 0, false
@@ -1882,8 +2084,14 @@ func findAtomInRange(f *os.File, start, size int64, target string, fileSize int6
 
 func findAudioSampleEntry(f *os.File, start, end, fileSize int64) (int64, string, error) {
 	const chunkSize = 64 * 1024
-	patternMP4A := []byte("mp4a")
-	patternALAC := []byte("alac")
+	patterns := [][]byte{
+		[]byte("mp4a"),
+		[]byte("alac"),
+		[]byte("fLaC"),
+		[]byte("ec-3"),
+		[]byte("ac-3"),
+		[]byte("ac-4"),
+	}
 
 	var tail []byte
 	readPos := start
@@ -1904,26 +2112,14 @@ func findAudioSampleEntry(f *os.File, start, end, fileSize int64) (int64, string
 		}
 
 		data := append(tail, buf[:n]...)
-		mp4aIdx := bytes.Index(data, patternMP4A)
-		alacIdx := bytes.Index(data, patternALAC)
-
 		bestIdx := -1
 		bestType := ""
-		switch {
-		case mp4aIdx >= 0 && alacIdx >= 0:
-			if mp4aIdx <= alacIdx {
-				bestIdx = mp4aIdx
-				bestType = "mp4a"
-			} else {
-				bestIdx = alacIdx
-				bestType = "alac"
+		for _, pattern := range patterns {
+			idx := bytes.Index(data, pattern)
+			if idx >= 0 && (bestIdx < 0 || idx < bestIdx) {
+				bestIdx = idx
+				bestType = string(pattern)
 			}
-		case mp4aIdx >= 0:
-			bestIdx = mp4aIdx
-			bestType = "mp4a"
-		case alacIdx >= 0:
-			bestIdx = alacIdx
-			bestType = "alac"
 		}
 
 		if bestIdx >= 0 {

go_backend/metadata_m4a_quality_test.go

@@ -47,3 +47,53 @@ func TestParseALACSpecificConfigRejectsShortPayload(t *testing.T) {
 		t.Fatal("expected short ALAC payload to be rejected")
 	}
 }
+
+func TestM4ACodecFormatMapping(t *testing.T) {
+	cases := map[string]string{
+		"mp4a": "aac",
+		"alac": "alac",
+		"fLaC": "flac",
+		"ec-3": "eac3",
+		"ac-3": "ac3",
+		"ac-4": "ac4",
+	}
+	for atomType, want := range cases {
+		if got := normalizeM4AAudioCodec(atomType); got != want {
+			t.Fatalf("normalizeM4AAudioCodec(%q) = %q, want %q", atomType, got, want)
+		}
+	}
+
+	if got := libraryFormatForM4ACodec("flac"); got != "flac" {
+		t.Fatalf("libraryFormatForM4ACodec(flac) = %q", got)
+	}
+	if got := libraryFormatForM4ACodec("eac3"); got != "eac3" {
+		t.Fatalf("libraryFormatForM4ACodec(eac3) = %q", got)
+	}
+	if got := libraryFormatForM4ACodec("aac"); got != "m4a" {
+		t.Fatalf("libraryFormatForM4ACodec(aac) = %q", got)
+	}
+}
+
+func TestParseMP4FLACSpecificConfig(t *testing.T) {
+	streamInfo := make([]byte, 34)
+	sampleRate := 48000
+	bitsPerSample := 24
+	totalSamples := int64(48000 * 180)
+	streamInfo[10] = byte(sampleRate >> 12)
+	streamInfo[11] = byte(sampleRate >> 4)
+	streamInfo[12] = byte((sampleRate&0x0F)<<4 | ((bitsPerSample-1)>>4)&0x01)
+	streamInfo[13] = byte(((bitsPerSample-1)&0x0F)<<4 | int((totalSamples>>32)&0x0F))
+	streamInfo[14] = byte(totalSamples >> 24)
+	streamInfo[15] = byte(totalSamples >> 16)
+	streamInfo[16] = byte(totalSamples >> 8)
+	streamInfo[17] = byte(totalSamples)
+
+	payload := append([]byte{0, 0, 0, 0, 0, 0, 0, 34}, streamInfo...)
+	bitDepth, parsedRate, parsedSamples, ok := parseMP4FLACSpecificConfig(payload)
+	if !ok {
+		t.Fatal("expected MP4 FLAC config to parse")
+	}
+	if bitDepth != bitsPerSample || parsedRate != sampleRate || parsedSamples != totalSamples {
+		t.Fatalf("FLAC config = %d/%d/%d", bitDepth, parsedRate, parsedSamples)
+	}
+}

go_backend/tls_roots.go

@@ -0,0 +1,82 @@
+package gobackend
+
+import (
+	"crypto/tls"
+	"crypto/x509"
+	"sync"
+)
+
+const isrgRootX1PEM = `-----BEGIN CERTIFICATE-----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=
+-----END CERTIFICATE-----`
+
+const isrgRootX2PEM = `-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----`
+
+var (
+	supplementalRootCAsOnce sync.Once
+	supplementalRootCAsPool *x509.CertPool
+)
+
+func supplementalRootCAs() *x509.CertPool {
+	supplementalRootCAsOnce.Do(func() {
+		pool, err := x509.SystemCertPool()
+		if err != nil || pool == nil {
+			pool = x509.NewCertPool()
+		}
+
+		for _, pem := range []string{isrgRootX1PEM, isrgRootX2PEM} {
+			pool.AppendCertsFromPEM([]byte(pem))
+		}
+		supplementalRootCAsPool = pool
+	})
+
+	return supplementalRootCAsPool
+}
+
+func newTLSCompatibilityConfig(insecureTLS bool) *tls.Config {
+	return &tls.Config{
+		RootCAs:            supplementalRootCAs(),
+		InsecureSkipVerify: insecureTLS,
+	}
+}

go_backend/wav_aiff.go

@@ -0,0 +1,975 @@
+package gobackend
+
+// WAV (RIFF) and AIFF/AIFC support: quality probing, tag reading/writing, and
+// cover-art extraction. These containers are not handled by go-flac, so chunks
+// are parsed/written by hand here.
+//
+// Tags are stored as an embedded ID3v2.4 tag (UTF-8): WAV uses a lowercase
+// "id3 " chunk, AIFF uses an uppercase "ID3 " chunk. ID3v2.4 is chosen because
+// the existing ID3 reader (parseID3v23Frames with version=4) reads synchsafe
+// frame sizes and UTF-8 text, so anything we write is read back losslessly.
+//
+// Reading also recognises a WAV "LIST"/"INFO" block as a fallback for files
+// that carry only RIFF INFO tags (common from other taggers).
+
+import (
+	"bytes"
+	"encoding/binary"
+	"fmt"
+	"io"
+	"math"
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+)
+
+// WAVQuality / AIFFQuality mirror the other GetXQuality result shapes.
+type WAVQuality struct {
+	SampleRate int
+	BitDepth   int
+	Channels   int
+	Duration   int
+}
+
+const (
+	wavMaxMetaChunk  = 16 * 1024 * 1024 // safety cap for buffering a metadata chunk
+	id3ChunkWAV      = "id3 "
+	id3ChunkAIFF     = "ID3 "
+	wavFormatPCM     = 0x0001
+	wavFormatFloat   = 0x0003
+	wavFormatExtensn = 0xFFFE
+)
+
+// ---------- low-level chunk size helpers ----------
+
+func putUint32(dst []byte, le bool, v uint32) {
+	if le {
+		binary.LittleEndian.PutUint32(dst, v)
+	} else {
+		binary.BigEndian.PutUint32(dst, v)
+	}
+}
+
+func readUint32(b []byte, le bool) uint32 {
+	if le {
+		return binary.LittleEndian.Uint32(b)
+	}
+	return binary.BigEndian.Uint32(b)
+}
+
+func synchsafeEncode(n int) []byte {
+	return []byte{
+		byte((n >> 21) & 0x7f),
+		byte((n >> 14) & 0x7f),
+		byte((n >> 7) & 0x7f),
+		byte(n & 0x7f),
+	}
+}
+
+func synchsafeDecode(b []byte) int {
+	if len(b) < 4 {
+		return 0
+	}
+	return int(b[0])<<21 | int(b[1])<<14 | int(b[2])<<7 | int(b[3])
+}
+
+// parseExtendedFloat80 decodes an 80-bit IEEE 754 extended float (used by the
+// AIFF COMM chunk for the sample rate).
+func parseExtendedFloat80(b []byte) float64 {
+	if len(b) < 10 {
+		return 0
+	}
+	sign := 1.0
+	if b[0]&0x80 != 0 {
+		sign = -1.0
+	}
+	exponent := int(b[0]&0x7f)<<8 | int(b[1])
+	var mantissa uint64
+	for i := 2; i < 10; i++ {
+		mantissa = mantissa<<8 | uint64(b[i])
+	}
+	if exponent == 0 && mantissa == 0 {
+		return 0
+	}
+	return sign * float64(mantissa) * math.Pow(2, float64(exponent-16383-63))
+}
+
+// ---------- WAV (RIFF) ----------
+
+type wavProbe struct {
+	sampleRate int
+	bitDepth   int
+	channels   int
+	byteRate   int
+	dataSize   int64
+	id3        []byte
+	info       map[string]string
+}
+
+// streamProbeWAV walks the top-level RIFF chunks, buffering only the small
+// metadata chunks (fmt/id3/LIST) and skipping the large data chunk.
+func streamProbeWAV(f *os.File) (*wavProbe, error) {
+	header := make([]byte, 12)
+	if _, err := io.ReadFull(f, header); err != nil {
+		return nil, err
+	}
+	if string(header[0:4]) != "RIFF" || string(header[8:12]) != "WAVE" {
+		return nil, fmt.Errorf("not a WAVE file")
+	}
+
+	p := &wavProbe{info: map[string]string{}}
+	hdr := make([]byte, 8)
+	for {
+		if _, err := io.ReadFull(f, hdr); err != nil {
+			break
+		}
+		id := string(hdr[0:4])
+		size := readUint32(hdr[4:8], true)
+		pad := int64(size) & 1
+
+		switch id {
+		case "fmt ":
+			buf := make([]byte, size)
+			if _, err := io.ReadFull(f, buf); err != nil {
+				return p, nil
+			}
+			if len(buf) >= 16 {
+				format := binary.LittleEndian.Uint16(buf[0:2])
+				p.channels = int(binary.LittleEndian.Uint16(buf[2:4]))
+				p.sampleRate = int(binary.LittleEndian.Uint32(buf[4:8]))
+				p.byteRate = int(binary.LittleEndian.Uint32(buf[8:12]))
+				p.bitDepth = int(binary.LittleEndian.Uint16(buf[14:16]))
+				if format == wavFormatExtensn && len(buf) >= 26 {
+					// Valid bits per sample lives in the extension; the real
+					// PCM format tag is in the GUID, but bitDepth from the
+					// container field is sufficient for display.
+					if vb := int(binary.LittleEndian.Uint16(buf[18:20])); vb > 0 {
+						p.bitDepth = vb
+					}
+				}
+			}
+			if pad == 1 {
+				f.Seek(pad, io.SeekCurrent)
+			}
+		case "data":
+			p.dataSize = int64(size)
+			f.Seek(int64(size)+pad, io.SeekCurrent)
+		case id3ChunkWAV, "ID3 ":
+			if size > 0 && size <= wavMaxMetaChunk {
+				buf := make([]byte, size)
+				if _, err := io.ReadFull(f, buf); err == nil {
+					p.id3 = buf
+				}
+				if pad == 1 {
+					f.Seek(pad, io.SeekCurrent)
+				}
+			} else {
+				f.Seek(int64(size)+pad, io.SeekCurrent)
+			}
+		case "LIST":
+			if size > 0 && size <= wavMaxMetaChunk {
+				buf := make([]byte, size)
+				if _, err := io.ReadFull(f, buf); err == nil {
+					parseRIFFInfo(buf, p.info)
+				}
+				if pad == 1 {
+					f.Seek(pad, io.SeekCurrent)
+				}
+			} else {
+				f.Seek(int64(size)+pad, io.SeekCurrent)
+			}
+		default:
+			f.Seek(int64(size)+pad, io.SeekCurrent)
+		}
+	}
+	return p, nil
+}
+
+// parseRIFFInfo reads a LIST/INFO block ("INFO" + sub-chunks like INAM, IART).
+func parseRIFFInfo(buf []byte, out map[string]string) {
+	if len(buf) < 4 || string(buf[0:4]) != "INFO" {
+		return
+	}
+	pos := 4
+	for pos+8 <= len(buf) {
+		id := string(buf[pos : pos+4])
+		size := int(binary.LittleEndian.Uint32(buf[pos+4 : pos+8]))
+		pos += 8
+		if size <= 0 || pos+size > len(buf) {
+			break
+		}
+		val := strings.TrimRight(string(buf[pos:pos+size]), "\x00")
+		out[id] = strings.TrimSpace(val)
+		pos += size
+		if size&1 == 1 {
+			pos++
+		}
+	}
+}
+
+func wavMetadataFromProbe(p *wavProbe) *AudioMetadata {
+	if p == nil {
+		return nil
+	}
+	if len(p.id3) > 0 {
+		if meta, err := readID3v2FromBytes(p.id3); err == nil && meta != nil &&
+			(meta.Title != "" || meta.Artist != "" || meta.Album != "") {
+			return meta
+		}
+	}
+	if len(p.info) > 0 {
+		meta := &AudioMetadata{
+			Title:     p.info["INAM"],
+			Artist:    p.info["IART"],
+			Album:     p.info["IPRD"],
+			Genre:     cleanGenre(p.info["IGNR"]),
+			Date:      p.info["ICRD"],
+			Comment:   p.info["ICMT"],
+			Copyright: p.info["ICOP"],
+			Composer:  p.info["IMUS"],
+		}
+		if n, err := strconv.Atoi(strings.TrimSpace(p.info["ITRK"])); err == nil {
+			meta.TrackNumber = n
+		}
+		if meta.Date != "" && len(meta.Date) >= 4 {
+			meta.Year = meta.Date[:4]
+		}
+		if meta.Title != "" || meta.Artist != "" || meta.Album != "" {
+			return meta
+		}
+	}
+	return nil
+}
+
+// GetWAVQuality probes PCM parameters and computes duration from the data size.
+func GetWAVQuality(filePath string) (*WAVQuality, error) {
+	f, err := os.Open(filePath)
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+
+	p, err := streamProbeWAV(f)
+	if err != nil {
+		return nil, err
+	}
+	q := &WAVQuality{
+		SampleRate: p.sampleRate,
+		BitDepth:   p.bitDepth,
+		Channels:   p.channels,
+	}
+	if p.byteRate > 0 && p.dataSize > 0 {
+		q.Duration = int(p.dataSize / int64(p.byteRate))
+	} else if p.sampleRate > 0 && p.channels > 0 && p.bitDepth > 0 && p.dataSize > 0 {
+		bytesPerSec := int64(p.sampleRate * p.channels * p.bitDepth / 8)
+		if bytesPerSec > 0 {
+			q.Duration = int(p.dataSize / bytesPerSec)
+		}
+	}
+	return q, nil
+}
+
+// ReadWAVTags reads tags from a WAV file (ID3 chunk preferred, RIFF INFO fallback).
+func ReadWAVTags(filePath string) (*AudioMetadata, error) {
+	f, err := os.Open(filePath)
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+
+	p, err := streamProbeWAV(f)
+	if err != nil {
+		return nil, err
+	}
+	meta := wavMetadataFromProbe(p)
+	if meta == nil {
+		return nil, fmt.Errorf("no WAV tags found")
+	}
+	return meta, nil
+}
+
+// ---------- AIFF / AIFC ----------
+
+type aiffProbe struct {
+	sampleRate     int
+	bitDepth       int
+	channels       int
+	numFrames      int64
+	id3            []byte
+	nameChunk      string
+	authChunk      string
+	annoChunk      string
+	copyrightChunk string
+}
+
+func streamProbeAIFF(f *os.File) (*aiffProbe, error) {
+	header := make([]byte, 12)
+	if _, err := io.ReadFull(f, header); err != nil {
+		return nil, err
+	}
+	form := string(header[8:12])
+	if string(header[0:4]) != "FORM" || (form != "AIFF" && form != "AIFC") {
+		return nil, fmt.Errorf("not an AIFF file")
+	}
+
+	p := &aiffProbe{}
+	hdr := make([]byte, 8)
+	for {
+		if _, err := io.ReadFull(f, hdr); err != nil {
+			break
+		}
+		id := string(hdr[0:4])
+		size := readUint32(hdr[4:8], false)
+		pad := int64(size) & 1
+
+		switch id {
+		case "COMM":
+			buf := make([]byte, size)
+			if _, err := io.ReadFull(f, buf); err != nil {
+				return p, nil
+			}
+			if len(buf) >= 18 {
+				p.channels = int(binary.BigEndian.Uint16(buf[0:2]))
+				p.numFrames = int64(binary.BigEndian.Uint32(buf[2:6]))
+				p.bitDepth = int(binary.BigEndian.Uint16(buf[6:8]))
+				p.sampleRate = int(parseExtendedFloat80(buf[8:18]) + 0.5)
+			}
+			if pad == 1 {
+				f.Seek(pad, io.SeekCurrent)
+			}
+		case id3ChunkAIFF, "id3 ":
+			if size > 0 && size <= wavMaxMetaChunk {
+				buf := make([]byte, size)
+				if _, err := io.ReadFull(f, buf); err == nil {
+					p.id3 = buf
+				}
+				if pad == 1 {
+					f.Seek(pad, io.SeekCurrent)
+				}
+			} else {
+				f.Seek(int64(size)+pad, io.SeekCurrent)
+			}
+		case "NAME", "AUTH", "ANNO", "(c) ":
+			if size > 0 && size <= wavMaxMetaChunk {
+				buf := make([]byte, size)
+				if _, err := io.ReadFull(f, buf); err == nil {
+					val := strings.TrimRight(strings.TrimSpace(string(buf)), "\x00")
+					switch id {
+					case "NAME":
+						p.nameChunk = val
+					case "AUTH":
+						p.authChunk = val
+					case "ANNO":
+						p.annoChunk = val
+					case "(c) ":
+						p.copyrightChunk = val
+					}
+				}
+				if pad == 1 {
+					f.Seek(pad, io.SeekCurrent)
+				}
+			} else {
+				f.Seek(int64(size)+pad, io.SeekCurrent)
+			}
+		default:
+			f.Seek(int64(size)+pad, io.SeekCurrent)
+		}
+	}
+	return p, nil
+}
+
+func aiffMetadataFromProbe(p *aiffProbe) *AudioMetadata {
+	if p == nil {
+		return nil
+	}
+	if len(p.id3) > 0 {
+		if meta, err := readID3v2FromBytes(p.id3); err == nil && meta != nil &&
+			(meta.Title != "" || meta.Artist != "" || meta.Album != "") {
+			return meta
+		}
+	}
+	if p.nameChunk != "" || p.authChunk != "" {
+		meta := &AudioMetadata{
+			Title:     p.nameChunk,
+			Artist:    p.authChunk,
+			Comment:   p.annoChunk,
+			Copyright: p.copyrightChunk,
+		}
+		return meta
+	}
+	return nil
+}
+
+// GetAIFFQuality probes PCM parameters and computes duration from frame count.
+func GetAIFFQuality(filePath string) (*WAVQuality, error) {
+	f, err := os.Open(filePath)
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+
+	p, err := streamProbeAIFF(f)
+	if err != nil {
+		return nil, err
+	}
+	q := &WAVQuality{
+		SampleRate: p.sampleRate,
+		BitDepth:   p.bitDepth,
+		Channels:   p.channels,
+	}
+	if p.sampleRate > 0 && p.numFrames > 0 {
+		q.Duration = int(p.numFrames / int64(p.sampleRate))
+	}
+	return q, nil
+}
+
+// ReadAIFFTags reads tags from an AIFF file (ID3 chunk preferred, AIFF text chunks fallback).
+func ReadAIFFTags(filePath string) (*AudioMetadata, error) {
+	f, err := os.Open(filePath)
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+
+	p, err := streamProbeAIFF(f)
+	if err != nil {
+		return nil, err
+	}
+	meta := aiffMetadataFromProbe(p)
+	if meta == nil {
+		return nil, fmt.Errorf("no AIFF tags found")
+	}
+	return meta, nil
+}
+
+// ---------- ID3v2 reading from a buffered chunk ----------
+
+// readID3v2FromBytes parses an in-memory ID3v2 tag (the contents of a WAV "id3 "
+// or AIFF "ID3 " chunk) by reusing the existing frame parsers.
+func readID3v2FromBytes(data []byte) (*AudioMetadata, error) {
+	if len(data) < 10 || string(data[0:3]) != "ID3" {
+		return nil, fmt.Errorf("no ID3v2 header")
+	}
+	majorVersion := data[3]
+	flags := data[5]
+	unsync := (flags & 0x80) != 0
+	extendedHeader := (flags & 0x40) != 0
+	footerPresent := (flags & 0x10) != 0
+
+	size := synchsafeDecode(data[6:10])
+	if size <= 0 || 10+size > len(data) {
+		size = len(data) - 10
+	}
+	tagData := data[10 : 10+size]
+
+	if footerPresent && len(tagData) >= 10 {
+		footerStart := len(tagData) - 10
+		if footerStart >= 0 && string(tagData[footerStart:footerStart+3]) == "3DI" {
+			tagData = tagData[:footerStart]
+		}
+	}
+	if extendedHeader {
+		if skip := extendedHeaderSize(tagData, majorVersion); skip > 0 && skip < len(tagData) {
+			tagData = tagData[skip:]
+		}
+	}
+
+	metadata := &AudioMetadata{}
+	if majorVersion == 2 {
+		parseID3v22Frames(tagData, metadata, unsync)
+	} else {
+		parseID3v23Frames(tagData, metadata, majorVersion, unsync)
+	}
+	return metadata, nil
+}
+
+// extractAPICFromID3 returns the first embedded picture (APIC/PIC) and its MIME.
+func extractAPICFromID3(tag []byte) ([]byte, string) {
+	if len(tag) < 10 || string(tag[0:3]) != "ID3" {
+		return nil, ""
+	}
+	ver := tag[3]
+	size := synchsafeDecode(tag[6:10])
+	if size <= 0 || 10+size > len(tag) {
+		size = len(tag) - 10
+	}
+	data := tag[10 : 10+size]
+
+	pos := 0
+	for {
+		if ver == 2 {
+			if pos+6 > len(data) || data[pos] == 0 {
+				break
+			}
+			id := string(data[pos : pos+3])
+			fsz := int(data[pos+3])<<16 | int(data[pos+4])<<8 | int(data[pos+5])
+			if fsz <= 0 || pos+6+fsz > len(data) {
+				break
+			}
+			if id == "PIC" {
+				return parseAPICFrame(data[pos+6:pos+6+fsz], ver)
+			}
+			pos += 6 + fsz
+			continue
+		}
+
+		if pos+10 > len(data) || data[pos] == 0 {
+			break
+		}
+		id := string(data[pos : pos+4])
+		var fsz int
+		if ver == 4 {
+			fsz = synchsafeDecode(data[pos+4 : pos+8])
+		} else {
+			fsz = int(binary.BigEndian.Uint32(data[pos+4 : pos+8]))
+		}
+		if fsz <= 0 || pos+10+fsz > len(data) {
+			break
+		}
+		if id == "APIC" {
+			return parseAPICFrame(data[pos+10:pos+10+fsz], ver)
+		}
+		pos += 10 + fsz
+	}
+	return nil, ""
+}
+
+// ---------- ID3v2.4 building ----------
+
+// buildID3v24Tag builds a UTF-8 ID3v2.4 tag from metadata plus optional cover.
+func buildID3v24Tag(meta *AudioMetadata, coverData []byte, coverMIME string) []byte {
+	var frames bytes.Buffer
+
+	writeFrame := func(id string, payload []byte) {
+		frames.WriteString(id)
+		frames.Write(synchsafeEncode(len(payload)))
+		frames.Write([]byte{0, 0})
+		frames.Write(payload)
+	}
+	writeText := func(id, val string) {
+		if strings.TrimSpace(val) == "" {
+			return
+		}
+		payload := append([]byte{0x03}, []byte(val)...)
+		writeFrame(id, payload)
+	}
+
+	writeText("TIT2", meta.Title)
+	writeText("TPE1", meta.Artist)
+	writeText("TALB", meta.Album)
+	writeText("TPE2", meta.AlbumArtist)
+	writeText("TCON", meta.Genre)
+	writeText("TCOM", meta.Composer)
+	writeText("TPUB", meta.Label)
+	writeText("TCOP", meta.Copyright)
+	writeText("TSRC", meta.ISRC)
+
+	date := meta.Date
+	if date == "" {
+		date = meta.Year
+	}
+	writeText("TDRC", date)
+
+	if meta.TrackNumber > 0 {
+		if meta.TotalTracks > 0 {
+			writeText("TRCK", fmt.Sprintf("%d/%d", meta.TrackNumber, meta.TotalTracks))
+		} else {
+			writeText("TRCK", strconv.Itoa(meta.TrackNumber))
+		}
+	}
+	if meta.DiscNumber > 0 {
+		if meta.TotalDiscs > 0 {
+			writeText("TPOS", fmt.Sprintf("%d/%d", meta.DiscNumber, meta.TotalDiscs))
+		} else {
+			writeText("TPOS", strconv.Itoa(meta.DiscNumber))
+		}
+	}
+
+	if strings.TrimSpace(meta.Comment) != "" {
+		// COMM: encoding + language(3) + short desc(null) + text
+		payload := []byte{0x03}
+		payload = append(payload, []byte("eng")...)
+		payload = append(payload, 0x00) // empty description
+		payload = append(payload, []byte(meta.Comment)...)
+		writeFrame("COMM", payload)
+	}
+	if strings.TrimSpace(meta.Lyrics) != "" {
+		payload := []byte{0x03}
+		payload = append(payload, []byte("eng")...)
+		payload = append(payload, 0x00)
+		payload = append(payload, []byte(meta.Lyrics)...)
+		writeFrame("USLT", payload)
+	}
+
+	// ReplayGain as TXXX (description\0value), UTF-8.
+	writeTXXX := func(desc, val string) {
+		if strings.TrimSpace(val) == "" {
+			return
+		}
+		payload := []byte{0x03}
+		payload = append(payload, []byte(desc)...)
+		payload = append(payload, 0x00)
+		payload = append(payload, []byte(val)...)
+		writeFrame("TXXX", payload)
+	}
+	writeTXXX("REPLAYGAIN_TRACK_GAIN", meta.ReplayGainTrackGain)
+	writeTXXX("REPLAYGAIN_TRACK_PEAK", meta.ReplayGainTrackPeak)
+	writeTXXX("REPLAYGAIN_ALBUM_GAIN", meta.ReplayGainAlbumGain)
+	writeTXXX("REPLAYGAIN_ALBUM_PEAK", meta.ReplayGainAlbumPeak)
+
+	if len(coverData) > 0 {
+		if strings.TrimSpace(coverMIME) == "" {
+			coverMIME = "image/jpeg"
+		}
+		// APIC: encoding + mime(null) + picture-type(0x03 front) + desc(null) + data
+		payload := []byte{0x03}
+		payload = append(payload, []byte(coverMIME)...)
+		payload = append(payload, 0x00)
+		payload = append(payload, 0x03)
+		payload = append(payload, 0x00)
+		payload = append(payload, coverData...)
+		writeFrame("APIC", payload)
+	}
+
+	body := frames.Bytes()
+	var out bytes.Buffer
+	out.WriteString("ID3")
+	out.Write([]byte{0x04, 0x00}) // v2.4.0
+	out.WriteByte(0x00)           // flags
+	out.Write(synchsafeEncode(len(body)))
+	out.Write(body)
+	return out.Bytes()
+}
+
+// ---------- tag writing (streaming chunk rewrite) ----------
+
+// writeID3Chunk rewrites filePath, replacing any existing tag chunk (chunkID,
+// matched case-insensitively) with a fresh ID3v2.4 chunk appended at the end.
+// The audio data and all other chunks are preserved; container size is patched.
+func writeID3Chunk(filePath, expectMagic, chunkID string, le bool, id3 []byte) error {
+	in, err := os.Open(filePath)
+	if err != nil {
+		return err
+	}
+	defer in.Close()
+
+	header := make([]byte, 12)
+	if _, err := io.ReadFull(in, header); err != nil {
+		return err
+	}
+	if string(header[0:4]) != expectMagic {
+		return fmt.Errorf("unexpected container magic %q", string(header[0:4]))
+	}
+
+	tmpPath := filePath + ".tagtmp"
+	out, err := os.Create(tmpPath)
+	if err != nil {
+		return err
+	}
+	cleanup := func() {
+		out.Close()
+		os.Remove(tmpPath)
+	}
+
+	if _, err := out.Write(header); err != nil {
+		cleanup()
+		return err
+	}
+
+	var bodyLen int64 = 4 // the 4-byte form type after the size field
+	hdr := make([]byte, 8)
+	for {
+		n, rerr := io.ReadFull(in, hdr)
+		if n < 8 {
+			break
+		}
+		if rerr != nil {
+			break
+		}
+		id := string(hdr[0:4])
+		size := readUint32(hdr[4:8], le)
+		pad := int64(size) & 1
+
+		if strings.EqualFold(id, chunkID) {
+			// Drop the existing tag chunk.
+			if _, err := in.Seek(int64(size)+pad, io.SeekCurrent); err != nil {
+				cleanup()
+				return err
+			}
+			continue
+		}
+
+		if _, err := out.Write(hdr); err != nil {
+			cleanup()
+			return err
+		}
+		if _, err := io.CopyN(out, in, int64(size)+pad); err != nil {
+			cleanup()
+			return err
+		}
+		bodyLen += 8 + int64(size) + pad
+	}
+
+	// Append the new tag chunk.
+	newSize := len(id3)
+	chunkHdr := make([]byte, 8)
+	copy(chunkHdr[0:4], chunkID)
+	putUint32(chunkHdr[4:8], le, uint32(newSize))
+	if _, err := out.Write(chunkHdr); err != nil {
+		cleanup()
+		return err
+	}
+	if _, err := out.Write(id3); err != nil {
+		cleanup()
+		return err
+	}
+	if newSize&1 == 1 {
+		if _, err := out.Write([]byte{0}); err != nil {
+			cleanup()
+			return err
+		}
+	}
+	bodyLen += 8 + int64(newSize) + int64(newSize&1)
+
+	// Patch the container size field (bytes 4..8).
+	sizeBuf := make([]byte, 4)
+	putUint32(sizeBuf, le, uint32(bodyLen))
+	if _, err := out.WriteAt(sizeBuf, 4); err != nil {
+		cleanup()
+		return err
+	}
+
+	if err := out.Close(); err != nil {
+		os.Remove(tmpPath)
+		return err
+	}
+	in.Close()
+
+	return os.Rename(tmpPath, filePath)
+}
+
+func loadCoverForTag(fields map[string]string) ([]byte, string) {
+	coverPath := strings.TrimSpace(fields["cover_path"])
+	if coverPath == "" {
+		return nil, ""
+	}
+	data, err := os.ReadFile(coverPath)
+	if err != nil || len(data) == 0 {
+		return nil, ""
+	}
+	mime := "image/jpeg"
+	if len(data) >= 8 && data[0] == 0x89 && data[1] == 0x50 && data[2] == 0x4E && data[3] == 0x47 {
+		mime = "image/png"
+	}
+	return data, mime
+}
+
+func audioMetadataFromEditFields(fields map[string]string) *AudioMetadata {
+	atoi := func(k string) int {
+		n := 0
+		if v, ok := fields[k]; ok && strings.TrimSpace(v) != "" {
+			fmt.Sscanf(strings.TrimSpace(v), "%d", &n)
+		}
+		return n
+	}
+	return &AudioMetadata{
+		Title:               fields["title"],
+		Artist:              fields["artist"],
+		Album:               fields["album"],
+		AlbumArtist:         fields["album_artist"],
+		Date:                fields["date"],
+		TrackNumber:         atoi("track_number"),
+		TotalTracks:         atoi("track_total"),
+		DiscNumber:          atoi("disc_number"),
+		TotalDiscs:          atoi("disc_total"),
+		ISRC:                fields["isrc"],
+		Lyrics:              fields["lyrics"],
+		Genre:               fields["genre"],
+		Label:               fields["label"],
+		Copyright:           fields["copyright"],
+		Composer:            fields["composer"],
+		Comment:             fields["comment"],
+		ReplayGainTrackGain: fields["replaygain_track_gain"],
+		ReplayGainTrackPeak: fields["replaygain_track_peak"],
+		ReplayGainAlbumGain: fields["replaygain_album_gain"],
+		ReplayGainAlbumPeak: fields["replaygain_album_peak"],
+	}
+}
+
+// mergeWAVEditFields merges edit fields onto existing tags so untouched fields
+// (and cover art, when no new cover is provided) are preserved.
+func mergeEditFieldsOntoExisting(existing *AudioMetadata, fields map[string]string) *AudioMetadata {
+	meta := audioMetadataFromEditFields(fields)
+	if existing == nil {
+		return meta
+	}
+	// Only overwrite fields that are present as keys in the edit set; otherwise
+	// keep the existing value. An empty value with the key present clears it.
+	keep := func(key, newVal, oldVal string) string {
+		if _, ok := fields[key]; ok {
+			return newVal
+		}
+		return oldVal
+	}
+	meta.Title = keep("title", meta.Title, existing.Title)
+	meta.Artist = keep("artist", meta.Artist, existing.Artist)
+	meta.Album = keep("album", meta.Album, existing.Album)
+	meta.AlbumArtist = keep("album_artist", meta.AlbumArtist, existing.AlbumArtist)
+	meta.Genre = keep("genre", meta.Genre, existing.Genre)
+	meta.Composer = keep("composer", meta.Composer, existing.Composer)
+	meta.Label = keep("label", meta.Label, existing.Label)
+	meta.Copyright = keep("copyright", meta.Copyright, existing.Copyright)
+	meta.ISRC = keep("isrc", meta.ISRC, existing.ISRC)
+	meta.Lyrics = keep("lyrics", meta.Lyrics, existing.Lyrics)
+	meta.Comment = keep("comment", meta.Comment, existing.Comment)
+	meta.Date = keep("date", meta.Date, existing.Date)
+	if _, ok := fields["track_number"]; !ok {
+		meta.TrackNumber = existing.TrackNumber
+	}
+	if _, ok := fields["track_total"]; !ok {
+		meta.TotalTracks = existing.TotalTracks
+	}
+	if _, ok := fields["disc_number"]; !ok {
+		meta.DiscNumber = existing.DiscNumber
+	}
+	if _, ok := fields["disc_total"]; !ok {
+		meta.TotalDiscs = existing.TotalDiscs
+	}
+	if _, ok := fields["replaygain_track_gain"]; !ok {
+		meta.ReplayGainTrackGain = existing.ReplayGainTrackGain
+	}
+	if _, ok := fields["replaygain_track_peak"]; !ok {
+		meta.ReplayGainTrackPeak = existing.ReplayGainTrackPeak
+	}
+	if _, ok := fields["replaygain_album_gain"]; !ok {
+		meta.ReplayGainAlbumGain = existing.ReplayGainAlbumGain
+	}
+	if _, ok := fields["replaygain_album_peak"]; !ok {
+		meta.ReplayGainAlbumPeak = existing.ReplayGainAlbumPeak
+	}
+	return meta
+}
+
+// WriteWAVTags writes/merges tags into a WAV file's "id3 " chunk.
+func WriteWAVTags(filePath string, fields map[string]string) error {
+	existing, _ := ReadWAVTags(filePath)
+	meta := mergeEditFieldsOntoExisting(existing, fields)
+
+	coverData, coverMIME := loadCoverForTag(fields)
+	if coverData == nil {
+		// Preserve an existing embedded cover when no new one is supplied.
+		if f, err := os.Open(filePath); err == nil {
+			if p, perr := streamProbeWAV(f); perr == nil && len(p.id3) > 0 {
+				coverData, coverMIME = extractAPICFromID3(p.id3)
+			}
+			f.Close()
+		}
+	}
+
+	tag := buildID3v24Tag(meta, coverData, coverMIME)
+	return writeID3Chunk(filePath, "RIFF", id3ChunkWAV, true, tag)
+}
+
+// WriteAIFFTags writes/merges tags into an AIFF file's "ID3 " chunk.
+func WriteAIFFTags(filePath string, fields map[string]string) error {
+	existing, _ := ReadAIFFTags(filePath)
+	meta := mergeEditFieldsOntoExisting(existing, fields)
+
+	coverData, coverMIME := loadCoverForTag(fields)
+	if coverData == nil {
+		if f, err := os.Open(filePath); err == nil {
+			if p, perr := streamProbeAIFF(f); perr == nil && len(p.id3) > 0 {
+				coverData, coverMIME = extractAPICFromID3(p.id3)
+			}
+			f.Close()
+		}
+	}
+
+	tag := buildID3v24Tag(meta, coverData, coverMIME)
+	return writeID3Chunk(filePath, "FORM", id3ChunkAIFF, false, tag)
+}
+
+// ---------- library scan integration ----------
+
+func scanWAVFile(filePath string, result *LibraryScanResult, displayNameHint string) (*LibraryScanResult, error) {
+	if metadata, err := ReadWAVTags(filePath); err == nil && metadata != nil {
+		applyAudioMetadataToScan(metadata, result)
+	}
+	if quality, err := GetWAVQuality(filePath); err == nil && quality != nil {
+		result.BitDepth = quality.BitDepth
+		result.SampleRate = quality.SampleRate
+		result.Duration = quality.Duration
+	}
+	result.Bitrate = 0 // lossless PCM
+	result.Format = "wav"
+	applyDefaultLibraryMetadata(filePath, displayNameHint, result)
+	return result, nil
+}
+
+func scanAIFFFile(filePath string, result *LibraryScanResult, displayNameHint string) (*LibraryScanResult, error) {
+	if metadata, err := ReadAIFFTags(filePath); err == nil && metadata != nil {
+		applyAudioMetadataToScan(metadata, result)
+	}
+	if quality, err := GetAIFFQuality(filePath); err == nil && quality != nil {
+		result.BitDepth = quality.BitDepth
+		result.SampleRate = quality.SampleRate
+		result.Duration = quality.Duration
+	}
+	result.Bitrate = 0 // lossless PCM
+	result.Format = "aiff"
+	applyDefaultLibraryMetadata(filePath, displayNameHint, result)
+	return result, nil
+}
+
+func applyAudioMetadataToScan(metadata *AudioMetadata, result *LibraryScanResult) {
+	result.TrackName = metadata.Title
+	result.ArtistName = metadata.Artist
+	result.AlbumName = metadata.Album
+	result.AlbumArtist = metadata.AlbumArtist
+	result.ISRC = metadata.ISRC
+	result.TrackNumber = metadata.TrackNumber
+	result.TotalTracks = metadata.TotalTracks
+	result.DiscNumber = metadata.DiscNumber
+	result.TotalDiscs = metadata.TotalDiscs
+	if metadata.Date != "" {
+		result.ReleaseDate = metadata.Date
+	} else {
+		result.ReleaseDate = metadata.Year
+	}
+	result.Genre = metadata.Genre
+	result.Composer = metadata.Composer
+	result.Label = metadata.Label
+	result.Copyright = metadata.Copyright
+}
+
+// extractWAVAIFFCover returns embedded cover art (from the ID3 chunk) for a
+// WAV or AIFF file, or an error when none is present.
+func extractWAVAIFFCover(filePath string) ([]byte, string, error) {
+	ext := strings.ToLower(filepath.Ext(filePath))
+	f, err := os.Open(filePath)
+	if err != nil {
+		return nil, "", err
+	}
+	defer f.Close()
+
+	var id3 []byte
+	switch ext {
+	case ".aiff", ".aif", ".aifc":
+		if p, perr := streamProbeAIFF(f); perr == nil {
+			id3 = p.id3
+		}
+	default:
+		if p, perr := streamProbeWAV(f); perr == nil {
+			id3 = p.id3
+		}
+	}
+	if len(id3) == 0 {
+		return nil, "", fmt.Errorf("no embedded cover")
+	}
+	data, mime := extractAPICFromID3(id3)
+	if len(data) == 0 {
+		return nil, "", fmt.Errorf("no embedded cover")
+	}
+	return data, mime, nil
+}

ios/Flutter/AppFrameworkInfo.plist

@@ -21,6 +21,6 @@
   <key>CFBundleVersion</key>
   <string>1.0</string>
   <key>MinimumOSVersion</key>
-  <string>13.0</string>
+  <string>14.0</string>
 </dict>
 </plist>

ios/Runner.xcodeproj/project.pbxproj

@@ -346,7 +346,7 @@
 				GCC_WARN_UNINITIALIZED_AUTOS = YES_AGGRESSIVE;
 				GCC_WARN_UNUSED_FUNCTION = YES;
 				GCC_WARN_UNUSED_VARIABLE = YES;
-				IPHONEOS_DEPLOYMENT_TARGET = 13.0;
+				IPHONEOS_DEPLOYMENT_TARGET = 14.0;
 				MTL_ENABLE_DEBUG_INFO = NO;
 				SDKROOT = iphoneos;
 				SUPPORTED_PLATFORMS = iphoneos;
@@ -472,7 +472,7 @@
 				GCC_WARN_UNINITIALIZED_AUTOS = YES_AGGRESSIVE;
 				GCC_WARN_UNUSED_FUNCTION = YES;
 				GCC_WARN_UNUSED_VARIABLE = YES;
-				IPHONEOS_DEPLOYMENT_TARGET = 13.0;
+				IPHONEOS_DEPLOYMENT_TARGET = 14.0;
 				MTL_ENABLE_DEBUG_INFO = YES;
 				ONLY_ACTIVE_ARCH = YES;
 				SDKROOT = iphoneos;
@@ -523,7 +523,7 @@
 				GCC_WARN_UNINITIALIZED_AUTOS = YES_AGGRESSIVE;
 				GCC_WARN_UNUSED_FUNCTION = YES;
 				GCC_WARN_UNUSED_VARIABLE = YES;
-				IPHONEOS_DEPLOYMENT_TARGET = 13.0;
+				IPHONEOS_DEPLOYMENT_TARGET = 14.0;
 				MTL_ENABLE_DEBUG_INFO = NO;
 				SDKROOT = iphoneos;
 				SUPPORTED_PLATFORMS = iphoneos;

ios/Runner/AppDelegate.swift

@@ -20,6 +20,11 @@ import Gobackend  // Import Go framework
     
     /// Currently accessed security-scoped URL for library folder
     private var activeSecurityScopedURL: URL?
+
+    /// Whether a download queue is active; while true a background task is
+    /// started on each background entry to extend execution time. Main-thread only.
+    private var downloadsActive = false
+    private var downloadBackgroundTask: UIBackgroundTaskIdentifier = .invalid
     
     override func application(
         _ application: UIApplication,
@@ -233,6 +238,20 @@ import Gobackend  // Import Go framework
     }
     
     private func handleMethodCall(call: FlutterMethodCall, result: @escaping FlutterResult) {
+        switch call.method {
+        case "beginBackgroundDownloadTask":
+            downloadsActive = true
+            result(nil)
+            return
+        case "endBackgroundDownloadTask":
+            downloadsActive = false
+            endBackgroundDownloadTask()
+            result(nil)
+            return
+        default:
+            break
+        }
+
         DispatchQueue.global(qos: .userInitiated).async {
             do {
                 let response = try self.invokeGoMethod(call: call)
@@ -246,6 +265,34 @@ import Gobackend  // Import Go framework
             }
         }
     }
+
+    override func applicationDidEnterBackground(_ application: UIApplication) {
+        super.applicationDidEnterBackground(application)
+        if downloadsActive {
+            beginBackgroundDownloadTask()
+        }
+    }
+
+    override func applicationWillEnterForeground(_ application: UIApplication) {
+        super.applicationWillEnterForeground(application)
+        endBackgroundDownloadTask()
+    }
+
+    private func beginBackgroundDownloadTask() {
+        if downloadBackgroundTask != .invalid { return }
+        downloadBackgroundTask = UIApplication.shared.beginBackgroundTask(
+            withName: "SpotiFLACDownloads"
+        ) { [weak self] in
+            self?.endBackgroundDownloadTask()
+        }
+    }
+
+    private func endBackgroundDownloadTask() {
+        if downloadBackgroundTask != .invalid {
+            UIApplication.shared.endBackgroundTask(downloadBackgroundTask)
+            downloadBackgroundTask = .invalid
+        }
+    }
     
     private func invokeGoMethod(call: FlutterMethodCall) throws -> Any? {
         var error: NSError?

lib/app.dart

@@ -114,6 +114,15 @@ class SpotiFLACApp extends ConsumerWidget {
           scrollBehavior: scrollBehavior,
           themeAnimationDuration: const Duration(milliseconds: 300),
           themeAnimationCurve: Curves.easeInOut,
+          // Treat the display as one continuous surface so bottom sheets and
+          // dialogs stay centered on large/foldable devices.
+          builder: (context, child) {
+            final mediaQuery = MediaQuery.of(context);
+            return MediaQuery(
+              data: mediaQuery.copyWith(displayFeatures: const []),
+              child: child ?? const SizedBox.shrink(),
+            );
+          },
           routerConfig: router,
           locale: locale,
           localeResolutionCallback: (deviceLocale, supportedLocales) {

lib/constants/app_info.dart

@@ -1,8 +1,8 @@
 import 'package:flutter/foundation.dart';
 
 class AppInfo {
-  static const String version = '4.5.1';
-  static const String buildNumber = '128';
+  static const String version = '4.6.0';
+  static const String buildNumber = '135';
   static const String fullVersion = '$version+$buildNumber';
 
   static String get displayVersion => kDebugMode ? 'Internal' : version;
@@ -17,6 +17,8 @@ class AppInfo {
   static const String githubUrl = 'https://github.com/$githubRepo';
   static const String originalGithubUrl =
       'https://github.com/afkarxyz/SpotiFLAC';
+  static const String remoteConfigApiUrl =
+      'https://api.zarz.moe/v1/spotiflac-mobile/config';
 
   static const String kofiUrl = 'https://ko-fi.com/zarzet';
   static const String githubSponsorsUrl = 'https://github.com/sponsors/zarzet/';

lib/l10n/app_localizations_en.dart

@@ -142,7 +142,7 @@ class AppLocalizationsEn extends AppLocalizations {
 
   @override
   String get optionsSwitchBack =>
-      'Tap Deezer or Spotify to switch back from extension';
+      'Choose the default search provider to switch back from an extension';
 
   @override
   String get optionsAutoFallback => 'Auto Fallback';
@@ -155,10 +155,12 @@ class AppLocalizationsEn extends AppLocalizations {
   String get optionsUseExtensionProviders => 'Use Extension Providers';
 
   @override
-  String get optionsUseExtensionProvidersOn => 'Extensions will be tried first';
+  String get optionsUseExtensionProvidersOn =>
+      'Extension providers are enabled';
 
   @override
-  String get optionsUseExtensionProvidersOff => 'Using built-in providers only';
+  String get optionsUseExtensionProvidersOff =>
+      'Extension providers are required';
 
   @override
   String get optionsEmbedLyrics => 'Embed Lyrics';
@@ -185,6 +187,43 @@ class AppLocalizationsEn extends AppLocalizations {
   String get optionsReplayGainSubtitleOff =>
       'Disabled: no loudness normalization tags';
 
+  @override
+  String get trackReplayGain => 'Rescan ReplayGain';
+
+  @override
+  String get trackReplayGainSubtitle =>
+      'Analyze loudness and write ReplayGain tags';
+
+  @override
+  String get trackReplayGainScanning => 'Analyzing loudness...';
+
+  @override
+  String get trackReplayGainSuccess => 'ReplayGain tags added';
+
+  @override
+  String get trackReplayGainFailed => 'Failed to add ReplayGain tags';
+
+  @override
+  String selectionReplayGainCount(int count) {
+    return 'ReplayGain ($count)';
+  }
+
+  @override
+  String get replayGainBatchConfirmTitle => 'Add ReplayGain';
+
+  @override
+  String replayGainBatchConfirmMessage(int count) {
+    return 'Analyze loudness and write ReplayGain tags to $count track(s)?';
+  }
+
+  @override
+  String get replayGainBatchAnalyzing => 'Analyzing ReplayGain...';
+
+  @override
+  String replayGainBatchSuccess(int success, int total) {
+    return 'ReplayGain added to $success of $total tracks';
+  }
+
   @override
   String get optionsArtistTagMode => 'Artist Tag Mode';
 
@@ -206,21 +245,6 @@ class AppLocalizationsEn extends AppLocalizations {
   String get optionsArtistTagModeSplitVorbisSubtitle =>
       'Write one artist tag per artist for FLAC and Opus; MP3 and M4A stay joined.';
 
-  @override
-  String get optionsConcurrentDownloads => 'Concurrent Downloads';
-
-  @override
-  String get optionsConcurrentSequential => 'Sequential (1 at a time)';
-
-  @override
-  String optionsConcurrentParallel(int count) {
-    return '$count parallel downloads';
-  }
-
-  @override
-  String get optionsConcurrentWarning =>
-      'Parallel downloads may trigger rate limiting';
-
   @override
   String get optionsExtensionStore => 'Extension Repo';
 
@@ -385,11 +409,11 @@ class AppLocalizationsEn extends AppLocalizations {
 
   @override
   String get aboutBinimumDesc =>
-      'The creator of QQDL & HiFi API. Without this API, Tidal downloads wouldn\'t exist!';
+      'The creator of QQDL & HiFi API. This project helped shape lossless download support.';
 
   @override
   String get aboutSachinsenalDesc =>
-      'The original HiFi project creator. The foundation of Tidal integration!';
+      'The original HiFi project creator. A foundation for lossless-source integration.';
 
   @override
   String get aboutSjdonadoDesc =>
@@ -397,7 +421,7 @@ class AppLocalizationsEn extends AppLocalizations {
 
   @override
   String get aboutAppDescription =>
-      'Download Spotify tracks in lossless quality from Tidal and Qobuz.';
+      'Search music metadata, manage extensions, and organize your library.';
 
   @override
   String get artistAlbums => 'Albums';
@@ -742,6 +766,9 @@ class AppLocalizationsEn extends AppLocalizations {
   @override
   String get errorNoTracksFound => 'No tracks found';
 
+  @override
+  String get searchEmptyResultSubtitle => 'Try another keyword';
+
   @override
   String get errorUrlNotRecognized => 'Link not recognized';
 
@@ -950,7 +977,7 @@ class AppLocalizationsEn extends AppLocalizations {
       'Only enabled extensions with download-provider capability are listed here.';
 
   @override
-  String get providerBuiltIn => 'Built-in';
+  String get providerBuiltIn => 'Legacy';
 
   @override
   String get providerExtension => 'Extension';
@@ -1220,6 +1247,11 @@ class AppLocalizationsEn extends AppLocalizations {
   @override
   String get trackCopyLyrics => 'Copy lyrics';
 
+  @override
+  String trackLyricsSource(String source) {
+    return 'Source: $source';
+  }
+
   @override
   String get trackLyricsNotAvailable => 'Lyrics not available for this track';
 
@@ -1338,10 +1370,11 @@ class AppLocalizationsEn extends AppLocalizations {
   String get storeEmptyNoResults => 'No extensions found';
 
   @override
-  String get extensionDefaultProvider => 'Default (Deezer)';
+  String get extensionDefaultProvider => 'Default Search';
 
   @override
-  String get extensionDefaultProviderSubtitle => 'Use built-in search';
+  String get extensionDefaultProviderSubtitle =>
+      'Use the default metadata search';
 
   @override
   String get extensionAuthor => 'Author';
@@ -1515,7 +1548,7 @@ class AppLocalizationsEn extends AppLocalizations {
 
   @override
   String get downloadLossy320FormatDesc =>
-      'Choose the output format for Tidal 320kbps lossy downloads. The original AAC stream will be converted to your selected format.';
+      'Choose the output format for 320kbps lossy downloads. The original stream will be converted to your selected format when needed.';
 
   @override
   String get downloadLossyMp3 => 'MP3 320kbps';
@@ -1523,6 +1556,13 @@ class AppLocalizationsEn extends AppLocalizations {
   @override
   String get downloadLossyMp3Subtitle => 'Best compatibility, ~10MB per track';
 
+  @override
+  String get downloadLossyAac => 'AAC/M4A 320kbps';
+
+  @override
+  String get downloadLossyAacSubtitle =>
+      'Best mobile compatibility, M4A container';
+
   @override
   String get downloadLossyOpus256 => 'Opus 256kbps';
 
@@ -1895,7 +1935,7 @@ class AppLocalizationsEn extends AppLocalizations {
 
   @override
   String get libraryAboutDescription =>
-      'Scans your existing music collection to detect duplicates when downloading. Supports FLAC, M4A, MP3, Opus, and OGG formats. Metadata is read from file tags when available.';
+      'Scans your existing music collection to detect duplicates when downloading. Supports FLAC, ALAC, M4A, MP3, Opus, OGG, WAV, AIFF, and APE formats. Metadata is read from file tags when available.';
 
   @override
   String libraryTracksUnit(int count) {
@@ -2078,7 +2118,7 @@ class AppLocalizationsEn extends AppLocalizations {
 
   @override
   String get tutorialWelcomeTip2 =>
-      'Get FLAC quality audio from Tidal, Qobuz, or Deezer';
+      'Get FLAC quality audio from installed download extensions';
 
   @override
   String get tutorialWelcomeTip3 =>
@@ -2408,7 +2448,7 @@ class AppLocalizationsEn extends AppLocalizations {
 
   @override
   String get trackConvertFormatSubtitle =>
-      'Convert to MP3, Opus, ALAC, or FLAC';
+      'Convert to AAC/M4A, MP3, Opus, ALAC, or FLAC';
 
   @override
   String get trackConvertTitle => 'Convert Audio';
@@ -2776,7 +2816,7 @@ class AppLocalizationsEn extends AppLocalizations {
 
   @override
   String get lyricsProvidersInfoText =>
-      'Extension lyrics providers always run before built-in providers. At least one provider must remain enabled.';
+      'Extension lyrics providers run before built-in lyrics providers. At least one provider must remain enabled.';
 
   @override
   String lyricsProvidersEnabledSection(int count) {
@@ -2818,6 +2858,10 @@ class AppLocalizationsEn extends AppLocalizations {
   String get lyricsProviderQqMusicDesc =>
       'QQ Music (good for Chinese songs, via proxy)';
 
+  @override
+  String get lyricsProviderLyricsPlusDesc =>
+      'Word-by-word karaoke lyrics (Apple/Musixmatch/Spotify/QQ, via proxy)';
+
   @override
   String get lyricsProviderExtensionDesc => 'Extension provider';
 
@@ -2972,11 +3016,11 @@ class AppLocalizationsEn extends AppLocalizations {
 
   @override
   String get downloadSelectServiceToEnable =>
-      'Select Tidal or Qobuz to enable this option';
+      'Select a provider with quality options to enable this option';
 
   @override
   String get downloadSelectTidalQobuz =>
-      'Select Tidal or Qobuz to choose audio quality';
+      'Select a provider with quality options to choose audio quality';
 
   @override
   String get downloadEmbedLyricsDisabled => 'Enable metadata embedding first';
@@ -3015,6 +3059,17 @@ class AppLocalizationsEn extends AppLocalizations {
   String get downloadAppleQqMultiPersonDisabled =>
       'Standard lyrics without speaker labels';
 
+  @override
+  String get downloadAppleElrcWordSync => 'Apple Music eLRC Word Sync';
+
+  @override
+  String get downloadAppleElrcWordSyncEnabled =>
+      'Raw word-by-word timestamps preserved';
+
+  @override
+  String get downloadAppleElrcWordSyncDisabled =>
+      'Safer line-by-line Apple Music lyrics';
+
   @override
   String get downloadMusixmatchLanguage => 'Musixmatch Language';
 
@@ -3260,6 +3315,15 @@ class AppLocalizationsEn extends AppLocalizations {
   @override
   String get audioAnalysisSampleRate => 'Sample Rate';
 
+  @override
+  String get audioAnalysisCodec => 'Codec';
+
+  @override
+  String get audioAnalysisContainer => 'Container';
+
+  @override
+  String get audioAnalysisDecodedFormat => 'Decoded Format';
+
   @override
   String get audioAnalysisBitDepth => 'Bit Depth';
 
@@ -3284,9 +3348,33 @@ class AppLocalizationsEn extends AppLocalizations {
   @override
   String get audioAnalysisRms => 'RMS';
 
+  @override
+  String get audioAnalysisLufs => 'LUFS';
+
+  @override
+  String get audioAnalysisTruePeak => 'True Peak';
+
+  @override
+  String get audioAnalysisClipping => 'Clipping';
+
+  @override
+  String get audioAnalysisNoClipping => 'No clipping';
+
+  @override
+  String get audioAnalysisSpectralCutoff => 'Spectral Cutoff';
+
+  @override
+  String get audioAnalysisChannelStats => 'Per-channel Stats';
+
   @override
   String get audioAnalysisSamples => 'Samples';
 
+  @override
+  String get audioAnalysisRescan => 'Re-analyze';
+
+  @override
+  String get audioAnalysisRescanning => 'Re-analyzing audio...';
+
   @override
   String extensionsSearchWith(String providerName) {
     return 'Search with $providerName';
@@ -3611,6 +3699,13 @@ class AppLocalizationsEn extends AppLocalizations {
   @override
   String get queueDownloadCompleted => 'Download completed';
 
+  @override
+  String get queueRateLimitTitle => 'Service rate limited';
+
+  @override
+  String get queueRateLimitMessage =>
+      'This track may still be available. Wait a few minutes, reduce parallel downloads, then retry.';
+
   @override
   String appearanceSelectAccentColor(String hex) {
     return 'Select accent color $hex';
@@ -3804,4 +3899,379 @@ class AppLocalizationsEn extends AppLocalizations {
   @override
   String get downloadFallbackExtensionsSubtitle =>
       'Choose which extensions can be used as fallback';
+
+  @override
+  String get editMetadataFieldDateHint => 'YYYY-MM-DD or YYYY';
+
+  @override
+  String get editMetadataFieldTrackTotal => 'Track Total';
+
+  @override
+  String get editMetadataFieldDiscTotal => 'Disc Total';
+
+  @override
+  String get editMetadataFieldComposer => 'Composer';
+
+  @override
+  String get editMetadataFieldComment => 'Comment';
+
+  @override
+  String get editMetadataAdvanced => 'Advanced';
+
+  @override
+  String get libraryFilterMetadataMissingTrackNumber => 'Missing track number';
+
+  @override
+  String get libraryFilterMetadataMissingDiscNumber => 'Missing disc number';
+
+  @override
+  String get libraryFilterMetadataMissingArtist => 'Missing artist';
+
+  @override
+  String get libraryFilterMetadataIncorrectIsrcFormat =>
+      'Incorrect ISRC format';
+
+  @override
+  String get libraryFilterMetadataMissingLabel => 'Missing label';
+
+  @override
+  String collectionDeletePlaylistsMessage(int count) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'playlists',
+      one: 'playlist',
+    );
+    return 'Delete $count $_temp0?';
+  }
+
+  @override
+  String collectionPlaylistsDeleted(int count) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'playlists',
+      one: 'playlist',
+    );
+    return '$count $_temp0 deleted';
+  }
+
+  @override
+  String collectionAddedTracksToPlaylist(int count, String playlistName) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'tracks',
+      one: 'track',
+    );
+    return 'Added $count $_temp0 to $playlistName';
+  }
+
+  @override
+  String collectionAddedTracksToPlaylistWithExisting(
+    int count,
+    String playlistName,
+    int alreadyCount,
+  ) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'tracks',
+      one: 'track',
+    );
+    return 'Added $count $_temp0 to $playlistName ($alreadyCount already in playlist)';
+  }
+
+  @override
+  String itemCount(int count) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'items',
+      one: 'item',
+    );
+    return '$count $_temp0';
+  }
+
+  @override
+  String trackReEnrichSuccessWithFailures(
+    int successCount,
+    int total,
+    int failedCount,
+  ) {
+    return 'Metadata re-enriched successfully ($successCount/$total) - Failed: $failedCount';
+  }
+
+  @override
+  String selectionDeleteTracksCount(int count) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'tracks',
+      one: 'track',
+    );
+    return 'Delete $count $_temp0';
+  }
+
+  @override
+  String queueDownloadSpeedStatus(String speed) {
+    return 'Downloading - $speed MB/s';
+  }
+
+  @override
+  String get queueDownloadStarting => 'Starting...';
+
+  @override
+  String get a11ySelectTrack => 'Select track';
+
+  @override
+  String get a11yDeselectTrack => 'Deselect track';
+
+  @override
+  String a11yPlayTrackByArtist(String trackName, String artistName) {
+    return 'Play $trackName by $artistName';
+  }
+
+  @override
+  String storeExtensionsCount(int count) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'extensions',
+      one: 'extension',
+    );
+    return '$count $_temp0';
+  }
+
+  @override
+  String storeRequiresVersion(String version) {
+    return 'Requires v$version+';
+  }
+
+  @override
+  String get actionGo => 'Go';
+
+  @override
+  String get logIssueSummary => 'Issue Summary';
+
+  @override
+  String logTotalErrors(int count) {
+    return 'Total errors: $count';
+  }
+
+  @override
+  String logAffectedDomains(String domains) {
+    return 'Affected: $domains';
+  }
+
+  @override
+  String get libraryScanCancelled => 'Scan cancelled';
+
+  @override
+  String get libraryScanCancelledSubtitle =>
+      'You can retry the scan when ready.';
+
+  @override
+  String libraryDownloadsHistoryExcluded(int count) {
+    return '$count from Downloads history (excluded from list)';
+  }
+
+  @override
+  String get downloadNativeWorker => 'Native download worker';
+
+  @override
+  String get downloadNativeWorkerSubtitle =>
+      'Beta Android service worker for extension downloads';
+
+  @override
+  String get badgeBeta => 'BETA';
+
+  @override
+  String get extensionServiceStatus => 'Service Status';
+
+  @override
+  String get extensionServiceHealth => 'Service health';
+
+  @override
+  String extensionHealthChecksConfigured(int count) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'checks',
+      one: 'check',
+    );
+    return '$count $_temp0 configured';
+  }
+
+  @override
+  String get extensionOauthConnectHint =>
+      'Tap Connect to Spotify to fill this field.';
+
+  @override
+  String extensionLastChecked(String time) {
+    return 'Last checked $time';
+  }
+
+  @override
+  String get extensionRefreshStatus => 'Refresh status';
+
+  @override
+  String get extensionCustomUrlHandling => 'Custom URL Handling';
+
+  @override
+  String get extensionCustomUrlHandlingSubtitle =>
+      'This extension can handle links from these sites';
+
+  @override
+  String get extensionCustomUrlHandlingShareHint =>
+      'Share links from these sites to SpotiFLAC Mobile and this extension will handle them.';
+
+  @override
+  String extensionSettingsCount(int count) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'settings',
+      one: 'setting',
+    );
+    return '$count $_temp0';
+  }
+
+  @override
+  String get extensionHealthOnline => 'Online';
+
+  @override
+  String get extensionHealthDegraded => 'Degraded';
+
+  @override
+  String get extensionHealthOffline => 'Offline';
+
+  @override
+  String get extensionHealthNotConfigured => 'Not configured';
+
+  @override
+  String get extensionHealthUnknown => 'Unknown';
+
+  @override
+  String get extensionHealthRequired => 'required';
+
+  @override
+  String get extensionSettingNotSet => 'Not set';
+
+  @override
+  String get extensionActionFailed => 'Action failed';
+
+  @override
+  String get extensionEnterValue => 'Enter value';
+
+  @override
+  String get extensionHealthServiceOnline => 'Service online';
+
+  @override
+  String get extensionHealthServiceDegraded => 'Service degraded';
+
+  @override
+  String get extensionHealthServiceOffline => 'Service offline';
+
+  @override
+  String get extensionHealthServiceUnknown => 'Service status unknown';
+
+  @override
+  String get audioAnalysisStereo => 'Stereo';
+
+  @override
+  String get audioAnalysisMono => 'Mono';
+
+  @override
+  String trackOpenInService(String serviceName) {
+    return 'Open in $serviceName';
+  }
+
+  @override
+  String get trackLyricsEmbeddedSource => 'Embedded';
+
+  @override
+  String get unknownAlbum => 'Unknown Album';
+
+  @override
+  String get unknownArtist => 'Unknown Artist';
+
+  @override
+  String get permissionAudio => 'Audio';
+
+  @override
+  String get permissionStorage => 'Storage';
+
+  @override
+  String get permissionNotification => 'Notification';
+
+  @override
+  String get errorInvalidFolderSelected => 'Invalid folder selected';
+
+  @override
+  String get errorCouldNotKeepFolderAccess =>
+      'Could not keep access to the selected folder';
+
+  @override
+  String get storeAnyVersion => 'Any';
+
+  @override
+  String get storeCategoryMetadata => 'Metadata';
+
+  @override
+  String get storeCategoryDownload => 'Download';
+
+  @override
+  String get storeCategoryUtility => 'Utility';
+
+  @override
+  String get storeCategoryLyrics => 'Lyrics';
+
+  @override
+  String get storeCategoryIntegration => 'Integration';
+
+  @override
+  String get artistReleases => 'Releases';
+
+  @override
+  String get editMetadataSelectNone => 'None';
+
+  @override
+  String queueRetryAllFailed(int count) {
+    return 'Retry $count failed';
+  }
+
+  @override
+  String get settingsSaveDownloadHistory => 'Save download history';
+
+  @override
+  String get settingsSaveDownloadHistorySubtitle =>
+      'Keep completed downloads in history and library views';
+
+  @override
+  String get dialogDisableHistoryTitle => 'Turn off download history?';
+
+  @override
+  String get dialogDisableHistoryMessage =>
+      'Existing history will be cleared. Downloaded files will not be deleted.';
+
+  @override
+  String get dialogDisableAndClear => 'Turn off and clear';
+
+  @override
+  String get openInOtherServices => 'Open in Other Services';
+
+  @override
+  String get shareSheetNoExtensions => 'No other compatible services';
+
+  @override
+  String get shareSheetNotFound => 'Not found';
+
+  @override
+  String get shareSheetCopyLink => 'Copy Link';
+
+  @override
+  String shareSheetLinkCopied(Object service) {
+    return '$service link copied';
+  }
 }

lib/l10n/app_localizations_hi.dart

@@ -126,7 +126,7 @@ class AppLocalizationsHi extends AppLocalizations {
 
   @override
   String get optionsPrimaryProviderSubtitle =>
-      'Service used when searching by track name.';
+      'Service used for searching by track or album name';
 
   @override
   String optionsUsingExtension(String extensionName) {
@@ -142,7 +142,7 @@ class AppLocalizationsHi extends AppLocalizations {
 
   @override
   String get optionsSwitchBack =>
-      'Tap Deezer or Spotify to switch back from extension';
+      'Choose the default search provider to switch back from an extension';
 
   @override
   String get optionsAutoFallback => 'Auto Fallback';
@@ -155,17 +155,19 @@ class AppLocalizationsHi extends AppLocalizations {
   String get optionsUseExtensionProviders => 'Use Extension Providers';
 
   @override
-  String get optionsUseExtensionProvidersOn => 'Extensions will be tried first';
+  String get optionsUseExtensionProvidersOn =>
+      'Extension providers are enabled';
 
   @override
-  String get optionsUseExtensionProvidersOff => 'Using built-in providers only';
+  String get optionsUseExtensionProvidersOff =>
+      'Extension providers are required';
 
   @override
   String get optionsEmbedLyrics => 'Embed Lyrics';
 
   @override
   String get optionsEmbedLyricsSubtitle =>
-      'Embed synced lyrics into FLAC files';
+      'Save synced lyrics alongside your downloaded tracks';
 
   @override
   String get optionsMaxQualityCover => 'Max Quality Cover';
@@ -185,6 +187,43 @@ class AppLocalizationsHi extends AppLocalizations {
   String get optionsReplayGainSubtitleOff =>
       'Disabled: no loudness normalization tags';
 
+  @override
+  String get trackReplayGain => 'Rescan ReplayGain';
+
+  @override
+  String get trackReplayGainSubtitle =>
+      'Analyze loudness and write ReplayGain tags';
+
+  @override
+  String get trackReplayGainScanning => 'Analyzing loudness...';
+
+  @override
+  String get trackReplayGainSuccess => 'ReplayGain tags added';
+
+  @override
+  String get trackReplayGainFailed => 'Failed to add ReplayGain tags';
+
+  @override
+  String selectionReplayGainCount(int count) {
+    return 'ReplayGain ($count)';
+  }
+
+  @override
+  String get replayGainBatchConfirmTitle => 'Add ReplayGain';
+
+  @override
+  String replayGainBatchConfirmMessage(int count) {
+    return 'Analyze loudness and write ReplayGain tags to $count track(s)?';
+  }
+
+  @override
+  String get replayGainBatchAnalyzing => 'Analyzing ReplayGain...';
+
+  @override
+  String replayGainBatchSuccess(int success, int total) {
+    return 'ReplayGain added to $success of $total tracks';
+  }
+
   @override
   String get optionsArtistTagMode => 'Artist Tag Mode';
 
@@ -206,21 +245,6 @@ class AppLocalizationsHi extends AppLocalizations {
   String get optionsArtistTagModeSplitVorbisSubtitle =>
       'Write one artist tag per artist for FLAC and Opus; MP3 and M4A stay joined.';
 
-  @override
-  String get optionsConcurrentDownloads => 'Concurrent Downloads';
-
-  @override
-  String get optionsConcurrentSequential => 'Sequential (1 at a time)';
-
-  @override
-  String optionsConcurrentParallel(int count) {
-    return '$count parallel downloads';
-  }
-
-  @override
-  String get optionsConcurrentWarning =>
-      'Parallel downloads may trigger rate limiting';
-
   @override
   String get optionsExtensionStore => 'Extension Repo';
 
@@ -385,11 +409,11 @@ class AppLocalizationsHi extends AppLocalizations {
 
   @override
   String get aboutBinimumDesc =>
-      'The creator of QQDL & HiFi API. Without this API, Tidal downloads wouldn\'t exist!';
+      'The creator of QQDL & HiFi API. This project helped shape lossless download support.';
 
   @override
   String get aboutSachinsenalDesc =>
-      'The original HiFi project creator. The foundation of Tidal integration!';
+      'The original HiFi project creator. A foundation for lossless-source integration.';
 
   @override
   String get aboutSjdonadoDesc =>
@@ -397,7 +421,7 @@ class AppLocalizationsHi extends AppLocalizations {
 
   @override
   String get aboutAppDescription =>
-      'Download Spotify tracks in lossless quality from Tidal and Qobuz.';
+      'Search music metadata, manage extensions, and organize your library.';
 
   @override
   String get artistAlbums => 'Albums';
@@ -742,6 +766,9 @@ class AppLocalizationsHi extends AppLocalizations {
   @override
   String get errorNoTracksFound => 'No tracks found';
 
+  @override
+  String get searchEmptyResultSubtitle => 'Try another keyword';
+
   @override
   String get errorUrlNotRecognized => 'Link not recognized';
 
@@ -950,7 +977,7 @@ class AppLocalizationsHi extends AppLocalizations {
       'Only enabled extensions with download-provider capability are listed here.';
 
   @override
-  String get providerBuiltIn => 'Built-in';
+  String get providerBuiltIn => 'Legacy';
 
   @override
   String get providerExtension => 'Extension';
@@ -1118,10 +1145,10 @@ class AppLocalizationsHi extends AppLocalizations {
   String get settingsAppearanceSubtitle => 'Theme, colors, display';
 
   @override
-  String get settingsDownloadSubtitle => 'Service, quality, filename format';
+  String get settingsDownloadSubtitle => 'Service, quality, fallback';
 
   @override
-  String get settingsOptionsSubtitle => 'Fallback, lyrics, cover art, updates';
+  String get settingsOptionsSubtitle => 'Fallback, metadata, lyrics, cover art';
 
   @override
   String get settingsExtensionsSubtitle => 'Manage download providers';
@@ -1220,6 +1247,11 @@ class AppLocalizationsHi extends AppLocalizations {
   @override
   String get trackCopyLyrics => 'Copy lyrics';
 
+  @override
+  String trackLyricsSource(String source) {
+    return 'Source: $source';
+  }
+
   @override
   String get trackLyricsNotAvailable => 'Lyrics not available for this track';
 
@@ -1338,10 +1370,11 @@ class AppLocalizationsHi extends AppLocalizations {
   String get storeEmptyNoResults => 'No extensions found';
 
   @override
-  String get extensionDefaultProvider => 'Default (Deezer)';
+  String get extensionDefaultProvider => 'Default Search';
 
   @override
-  String get extensionDefaultProviderSubtitle => 'Use built-in search';
+  String get extensionDefaultProviderSubtitle =>
+      'Use the default metadata search';
 
   @override
   String get extensionAuthor => 'Author';
@@ -1515,7 +1548,7 @@ class AppLocalizationsHi extends AppLocalizations {
 
   @override
   String get downloadLossy320FormatDesc =>
-      'Choose the output format for Tidal 320kbps lossy downloads. The original AAC stream will be converted to your selected format.';
+      'Choose the output format for 320kbps lossy downloads. The original stream will be converted to your selected format when needed.';
 
   @override
   String get downloadLossyMp3 => 'MP3 320kbps';
@@ -1523,6 +1556,13 @@ class AppLocalizationsHi extends AppLocalizations {
   @override
   String get downloadLossyMp3Subtitle => 'Best compatibility, ~10MB per track';
 
+  @override
+  String get downloadLossyAac => 'AAC/M4A 320kbps';
+
+  @override
+  String get downloadLossyAacSubtitle =>
+      'Best mobile compatibility, M4A container';
+
   @override
   String get downloadLossyOpus256 => 'Opus 256kbps';
 
@@ -2078,7 +2118,7 @@ class AppLocalizationsHi extends AppLocalizations {
 
   @override
   String get tutorialWelcomeTip2 =>
-      'Get FLAC quality audio from Tidal, Qobuz, or Deezer';
+      'Get FLAC quality audio from installed download extensions';
 
   @override
   String get tutorialWelcomeTip3 =>
@@ -2408,7 +2448,7 @@ class AppLocalizationsHi extends AppLocalizations {
 
   @override
   String get trackConvertFormatSubtitle =>
-      'Convert to MP3, Opus, ALAC, or FLAC';
+      'Convert to AAC/M4A, MP3, Opus, ALAC, or FLAC';
 
   @override
   String get trackConvertTitle => 'Convert Audio';
@@ -2761,14 +2801,14 @@ class AppLocalizationsHi extends AppLocalizations {
 
   @override
   String get downloadUseAlbumArtistForFoldersAlbumSubtitle =>
-      'Artist folders use Album Artist when available';
+      'Folder named after Album Artist tag';
 
   @override
   String get downloadUseAlbumArtistForFoldersTrackSubtitle =>
-      'Artist folders use Track Artist only';
+      'Folder named after Track Artist tag';
 
   @override
-  String get lyricsProvidersTitle => 'Lyrics Providers';
+  String get lyricsProvidersTitle => 'Lyrics Provider Priority';
 
   @override
   String get lyricsProvidersDescription =>
@@ -2776,7 +2816,7 @@ class AppLocalizationsHi extends AppLocalizations {
 
   @override
   String get lyricsProvidersInfoText =>
-      'Extension lyrics providers always run before built-in providers. At least one provider must remain enabled.';
+      'Extension lyrics providers run before built-in lyrics providers. At least one provider must remain enabled.';
 
   @override
   String lyricsProvidersEnabledSection(int count) {
@@ -2818,6 +2858,10 @@ class AppLocalizationsHi extends AppLocalizations {
   String get lyricsProviderQqMusicDesc =>
       'QQ Music (good for Chinese songs, via proxy)';
 
+  @override
+  String get lyricsProviderLyricsPlusDesc =>
+      'Word-by-word karaoke lyrics (Apple/Musixmatch/Spotify/QQ, via proxy)';
+
   @override
   String get lyricsProviderExtensionDesc => 'Extension provider';
 
@@ -2836,10 +2880,10 @@ class AppLocalizationsHi extends AppLocalizations {
   String get safMigrationSuccess => 'Download folder updated to SAF mode';
 
   @override
-  String get settingsDonate => 'Donate';
+  String get settingsDonate => 'Support Development';
 
   @override
-  String get settingsDonateSubtitle => 'Support SpotiFLAC-Mobile development';
+  String get settingsDonateSubtitle => 'Buy the developer a coffee';
 
   @override
   String get tooltipLoveAll => 'Love All';
@@ -2899,20 +2943,20 @@ class AppLocalizationsHi extends AppLocalizations {
 
   @override
   String get downloadLocationSubtitle =>
-      'Choose storage mode for downloaded files.';
+      'Choose where to save your downloaded tracks';
 
   @override
-  String get storageModeAppFolder => 'App folder (non-SAF)';
+  String get storageModeAppFolder => 'App Folder (Recommended)';
 
   @override
-  String get storageModeAppFolderSubtitle => 'Use default Music/SpotiFLAC path';
+  String get storageModeAppFolderSubtitle =>
+      'Saves to Music/SpotiFLAC by default';
 
   @override
-  String get storageModeSaf => 'SAF folder';
+  String get storageModeSaf => 'Custom Folder (SAF)';
 
   @override
-  String get storageModeSafSubtitle =>
-      'Pick folder via Android Storage Access Framework';
+  String get storageModeSafSubtitle => 'Pick any folder, including SD card';
 
   @override
   String downloadFilenameDescription(
@@ -2924,62 +2968,62 @@ class AppLocalizationsHi extends AppLocalizations {
     Object track,
     Object year,
   ) {
-    return 'Customize how your files are named.';
+    return 'Use $artist, $title, $album, $track, $year, $date, $disc as placeholders.';
   }
 
   @override
   String get downloadFilenameInsertTag => 'Tap to insert tag:';
 
   @override
-  String get downloadSeparateSinglesEnabled => 'Albums/ and Singles/ folders';
+  String get downloadSeparateSinglesEnabled =>
+      'Singles and EPs saved in a separate folder';
 
   @override
-  String get downloadSeparateSinglesDisabled => 'All files in same structure';
+  String get downloadSeparateSinglesDisabled =>
+      'Singles and albums saved in the same folder';
 
   @override
   String get downloadArtistNameFilters => 'Artist Name Filters';
 
   @override
-  String get downloadCreatePlaylistSourceFolder =>
-      'Create playlist source folder';
+  String get downloadCreatePlaylistSourceFolder => 'Playlist Source Folder';
 
   @override
   String get downloadCreatePlaylistSourceFolderEnabled =>
-      'Playlist downloads use Playlist/ plus your normal folder structure.';
+      'A subfolder is created for each playlist';
 
   @override
   String get downloadCreatePlaylistSourceFolderDisabled =>
-      'Playlist downloads use the normal folder structure only.';
+      'All tracks saved directly to download folder';
 
   @override
   String get downloadCreatePlaylistSourceFolderRedundant =>
-      'By Playlist already places downloads inside a playlist folder.';
+      'Handled by folder organization setting';
 
   @override
   String get downloadSongLinkRegion => 'SongLink Region';
 
   @override
-  String get downloadNetworkCompatibilityMode => 'Network compatibility mode';
+  String get downloadNetworkCompatibilityMode => 'Network Compatibility Mode';
 
   @override
   String get downloadNetworkCompatibilityModeEnabled =>
-      'Enabled: try HTTP + accept invalid TLS certificates (unsafe)';
+      'Using legacy TLS settings for older networks';
 
   @override
   String get downloadNetworkCompatibilityModeDisabled =>
-      'Off: strict HTTPS certificate validation (recommended)';
+      'Using standard network settings';
 
   @override
   String get downloadSelectServiceToEnable =>
-      'Select a built-in service to enable';
+      'Select a provider with quality options to enable this option';
 
   @override
   String get downloadSelectTidalQobuz =>
-      'Select Tidal or Qobuz above to configure quality';
+      'Select a provider with quality options to choose audio quality';
 
   @override
-  String get downloadEmbedLyricsDisabled =>
-      'Disabled while Embed Metadata is turned off';
+  String get downloadEmbedLyricsDisabled => 'Enable metadata embedding first';
 
   @override
   String get downloadNeteaseIncludeTranslation =>
@@ -2987,11 +3031,11 @@ class AppLocalizationsHi extends AppLocalizations {
 
   @override
   String get downloadNeteaseIncludeTranslationEnabled =>
-      'Append translated lyrics when available';
+      'Chinese translation lines included';
 
   @override
   String get downloadNeteaseIncludeTranslationDisabled =>
-      'Use original lyrics only';
+      'Original lyrics only';
 
   @override
   String get downloadNeteaseIncludeRomanization =>
@@ -2999,66 +3043,76 @@ class AppLocalizationsHi extends AppLocalizations {
 
   @override
   String get downloadNeteaseIncludeRomanizationEnabled =>
-      'Append romanized lyrics when available';
+      'Romanization lines included';
 
   @override
-  String get downloadNeteaseIncludeRomanizationDisabled => 'Disabled';
+  String get downloadNeteaseIncludeRomanizationDisabled => 'No romanization';
 
   @override
-  String get downloadAppleQqMultiPerson => 'Apple/QQ Multi-Person Word-by-Word';
+  String get downloadAppleQqMultiPerson => 'Apple / QQ: Multi-Person Lyrics';
 
   @override
   String get downloadAppleQqMultiPersonEnabled =>
-      'Enable v1/v2 speaker and [bg:] tags';
+      'Speaker labels included for duets and group tracks';
 
   @override
   String get downloadAppleQqMultiPersonDisabled =>
-      'Simplified word-by-word formatting';
+      'Standard lyrics without speaker labels';
+
+  @override
+  String get downloadAppleElrcWordSync => 'Apple Music eLRC Word Sync';
+
+  @override
+  String get downloadAppleElrcWordSyncEnabled =>
+      'Raw word-by-word timestamps preserved';
+
+  @override
+  String get downloadAppleElrcWordSyncDisabled =>
+      'Safer line-by-line Apple Music lyrics';
 
   @override
   String get downloadMusixmatchLanguage => 'Musixmatch Language';
 
   @override
-  String get downloadMusixmatchLanguageAuto => 'Auto (original)';
+  String get downloadMusixmatchLanguageAuto => 'Auto (original language)';
 
   @override
-  String get downloadFilterContributing =>
-      'Filter contributing artists in Album Artist';
+  String get downloadFilterContributing => 'Filter Contributing Artists';
 
   @override
   String get downloadFilterContributingEnabled =>
-      'Album Artist metadata uses primary artist only';
+      'Contributing artists removed from Album Artist folder name';
 
   @override
   String get downloadFilterContributingDisabled =>
-      'Keep full Album Artist metadata value';
+      'Full Album Artist string used';
 
   @override
-  String get downloadProvidersNoneEnabled => 'None enabled';
+  String get downloadProvidersNoneEnabled => 'No providers enabled';
 
   @override
   String get downloadMusixmatchLanguageCode => 'Language code';
 
   @override
-  String get downloadMusixmatchLanguageHint => 'auto / en / es / ja';
+  String get downloadMusixmatchLanguageHint => 'e.g. en, de, ja';
 
   @override
   String get downloadMusixmatchLanguageDesc =>
-      'Set preferred language code (example: en, es, ja). Leave empty for auto.';
+      'Enter a BCP-47 language code (e.g. en, de, ja) to request translated lyrics from Musixmatch.';
 
   @override
   String get downloadMusixmatchAuto => 'Auto';
 
   @override
-  String get downloadNetworkAnySubtitle => 'WiFi + Mobile Data';
+  String get downloadNetworkAnySubtitle => 'Use WiFi or mobile data';
 
   @override
   String get downloadNetworkWifiOnlySubtitle =>
-      'Pause downloads on mobile data';
+      'Downloads pause when on mobile data';
 
   @override
   String get downloadSongLinkRegionDesc =>
-      'Used as userCountry for SongLink API lookup.';
+      'Region used when resolving track links via SongLink. Choose the country where your streaming services are available.';
 
   @override
   String get snackbarUnsupportedAudioFormat => 'Unsupported audio format';
@@ -3261,6 +3315,15 @@ class AppLocalizationsHi extends AppLocalizations {
   @override
   String get audioAnalysisSampleRate => 'Sample Rate';
 
+  @override
+  String get audioAnalysisCodec => 'Codec';
+
+  @override
+  String get audioAnalysisContainer => 'Container';
+
+  @override
+  String get audioAnalysisDecodedFormat => 'Decoded Format';
+
   @override
   String get audioAnalysisBitDepth => 'Bit Depth';
 
@@ -3285,9 +3348,33 @@ class AppLocalizationsHi extends AppLocalizations {
   @override
   String get audioAnalysisRms => 'RMS';
 
+  @override
+  String get audioAnalysisLufs => 'LUFS';
+
+  @override
+  String get audioAnalysisTruePeak => 'True Peak';
+
+  @override
+  String get audioAnalysisClipping => 'Clipping';
+
+  @override
+  String get audioAnalysisNoClipping => 'No clipping';
+
+  @override
+  String get audioAnalysisSpectralCutoff => 'Spectral Cutoff';
+
+  @override
+  String get audioAnalysisChannelStats => 'Per-channel Stats';
+
   @override
   String get audioAnalysisSamples => 'Samples';
 
+  @override
+  String get audioAnalysisRescan => 'Re-analyze';
+
+  @override
+  String get audioAnalysisRescanning => 'Re-analyzing audio...';
+
   @override
   String extensionsSearchWith(String providerName) {
     return 'Search with $providerName';
@@ -3411,7 +3498,13 @@ class AppLocalizationsHi extends AppLocalizations {
 
   @override
   String notifTracksDownloadedSuccess(int count) {
-    return '$count tracks downloaded successfully';
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: '$count tracks downloaded successfully',
+      one: '1 track downloaded successfully',
+    );
+    return '$_temp0';
   }
 
   @override
@@ -3606,6 +3699,13 @@ class AppLocalizationsHi extends AppLocalizations {
   @override
   String get queueDownloadCompleted => 'Download completed';
 
+  @override
+  String get queueRateLimitTitle => 'Service rate limited';
+
+  @override
+  String get queueRateLimitMessage =>
+      'This track may still be available. Wait a few minutes, reduce parallel downloads, then retry.';
+
   @override
   String appearanceSelectAccentColor(String hex) {
     return 'Select accent color $hex';
@@ -3799,4 +3899,379 @@ class AppLocalizationsHi extends AppLocalizations {
   @override
   String get downloadFallbackExtensionsSubtitle =>
       'Choose which extensions can be used as fallback';
+
+  @override
+  String get editMetadataFieldDateHint => 'YYYY-MM-DD or YYYY';
+
+  @override
+  String get editMetadataFieldTrackTotal => 'Track Total';
+
+  @override
+  String get editMetadataFieldDiscTotal => 'Disc Total';
+
+  @override
+  String get editMetadataFieldComposer => 'Composer';
+
+  @override
+  String get editMetadataFieldComment => 'Comment';
+
+  @override
+  String get editMetadataAdvanced => 'Advanced';
+
+  @override
+  String get libraryFilterMetadataMissingTrackNumber => 'Missing track number';
+
+  @override
+  String get libraryFilterMetadataMissingDiscNumber => 'Missing disc number';
+
+  @override
+  String get libraryFilterMetadataMissingArtist => 'Missing artist';
+
+  @override
+  String get libraryFilterMetadataIncorrectIsrcFormat =>
+      'Incorrect ISRC format';
+
+  @override
+  String get libraryFilterMetadataMissingLabel => 'Missing label';
+
+  @override
+  String collectionDeletePlaylistsMessage(int count) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'playlists',
+      one: 'playlist',
+    );
+    return 'Delete $count $_temp0?';
+  }
+
+  @override
+  String collectionPlaylistsDeleted(int count) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'playlists',
+      one: 'playlist',
+    );
+    return '$count $_temp0 deleted';
+  }
+
+  @override
+  String collectionAddedTracksToPlaylist(int count, String playlistName) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'tracks',
+      one: 'track',
+    );
+    return 'Added $count $_temp0 to $playlistName';
+  }
+
+  @override
+  String collectionAddedTracksToPlaylistWithExisting(
+    int count,
+    String playlistName,
+    int alreadyCount,
+  ) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'tracks',
+      one: 'track',
+    );
+    return 'Added $count $_temp0 to $playlistName ($alreadyCount already in playlist)';
+  }
+
+  @override
+  String itemCount(int count) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'items',
+      one: 'item',
+    );
+    return '$count $_temp0';
+  }
+
+  @override
+  String trackReEnrichSuccessWithFailures(
+    int successCount,
+    int total,
+    int failedCount,
+  ) {
+    return 'Metadata re-enriched successfully ($successCount/$total) - Failed: $failedCount';
+  }
+
+  @override
+  String selectionDeleteTracksCount(int count) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'tracks',
+      one: 'track',
+    );
+    return 'Delete $count $_temp0';
+  }
+
+  @override
+  String queueDownloadSpeedStatus(String speed) {
+    return 'Downloading - $speed MB/s';
+  }
+
+  @override
+  String get queueDownloadStarting => 'Starting...';
+
+  @override
+  String get a11ySelectTrack => 'Select track';
+
+  @override
+  String get a11yDeselectTrack => 'Deselect track';
+
+  @override
+  String a11yPlayTrackByArtist(String trackName, String artistName) {
+    return 'Play $trackName by $artistName';
+  }
+
+  @override
+  String storeExtensionsCount(int count) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'extensions',
+      one: 'extension',
+    );
+    return '$count $_temp0';
+  }
+
+  @override
+  String storeRequiresVersion(String version) {
+    return 'Requires v$version+';
+  }
+
+  @override
+  String get actionGo => 'Go';
+
+  @override
+  String get logIssueSummary => 'Issue Summary';
+
+  @override
+  String logTotalErrors(int count) {
+    return 'Total errors: $count';
+  }
+
+  @override
+  String logAffectedDomains(String domains) {
+    return 'Affected: $domains';
+  }
+
+  @override
+  String get libraryScanCancelled => 'Scan cancelled';
+
+  @override
+  String get libraryScanCancelledSubtitle =>
+      'You can retry the scan when ready.';
+
+  @override
+  String libraryDownloadsHistoryExcluded(int count) {
+    return '$count from Downloads history (excluded from list)';
+  }
+
+  @override
+  String get downloadNativeWorker => 'Native download worker';
+
+  @override
+  String get downloadNativeWorkerSubtitle =>
+      'Beta Android service worker for extension downloads';
+
+  @override
+  String get badgeBeta => 'BETA';
+
+  @override
+  String get extensionServiceStatus => 'Service Status';
+
+  @override
+  String get extensionServiceHealth => 'Service health';
+
+  @override
+  String extensionHealthChecksConfigured(int count) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'checks',
+      one: 'check',
+    );
+    return '$count $_temp0 configured';
+  }
+
+  @override
+  String get extensionOauthConnectHint =>
+      'Tap Connect to Spotify to fill this field.';
+
+  @override
+  String extensionLastChecked(String time) {
+    return 'Last checked $time';
+  }
+
+  @override
+  String get extensionRefreshStatus => 'Refresh status';
+
+  @override
+  String get extensionCustomUrlHandling => 'Custom URL Handling';
+
+  @override
+  String get extensionCustomUrlHandlingSubtitle =>
+      'This extension can handle links from these sites';
+
+  @override
+  String get extensionCustomUrlHandlingShareHint =>
+      'Share links from these sites to SpotiFLAC Mobile and this extension will handle them.';
+
+  @override
+  String extensionSettingsCount(int count) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'settings',
+      one: 'setting',
+    );
+    return '$count $_temp0';
+  }
+
+  @override
+  String get extensionHealthOnline => 'Online';
+
+  @override
+  String get extensionHealthDegraded => 'Degraded';
+
+  @override
+  String get extensionHealthOffline => 'Offline';
+
+  @override
+  String get extensionHealthNotConfigured => 'Not configured';
+
+  @override
+  String get extensionHealthUnknown => 'Unknown';
+
+  @override
+  String get extensionHealthRequired => 'required';
+
+  @override
+  String get extensionSettingNotSet => 'Not set';
+
+  @override
+  String get extensionActionFailed => 'Action failed';
+
+  @override
+  String get extensionEnterValue => 'Enter value';
+
+  @override
+  String get extensionHealthServiceOnline => 'Service online';
+
+  @override
+  String get extensionHealthServiceDegraded => 'Service degraded';
+
+  @override
+  String get extensionHealthServiceOffline => 'Service offline';
+
+  @override
+  String get extensionHealthServiceUnknown => 'Service status unknown';
+
+  @override
+  String get audioAnalysisStereo => 'Stereo';
+
+  @override
+  String get audioAnalysisMono => 'Mono';
+
+  @override
+  String trackOpenInService(String serviceName) {
+    return 'Open in $serviceName';
+  }
+
+  @override
+  String get trackLyricsEmbeddedSource => 'Embedded';
+
+  @override
+  String get unknownAlbum => 'Unknown Album';
+
+  @override
+  String get unknownArtist => 'Unknown Artist';
+
+  @override
+  String get permissionAudio => 'Audio';
+
+  @override
+  String get permissionStorage => 'Storage';
+
+  @override
+  String get permissionNotification => 'Notification';
+
+  @override
+  String get errorInvalidFolderSelected => 'Invalid folder selected';
+
+  @override
+  String get errorCouldNotKeepFolderAccess =>
+      'Could not keep access to the selected folder';
+
+  @override
+  String get storeAnyVersion => 'Any';
+
+  @override
+  String get storeCategoryMetadata => 'Metadata';
+
+  @override
+  String get storeCategoryDownload => 'Download';
+
+  @override
+  String get storeCategoryUtility => 'Utility';
+
+  @override
+  String get storeCategoryLyrics => 'Lyrics';
+
+  @override
+  String get storeCategoryIntegration => 'Integration';
+
+  @override
+  String get artistReleases => 'Releases';
+
+  @override
+  String get editMetadataSelectNone => 'None';
+
+  @override
+  String queueRetryAllFailed(int count) {
+    return 'Retry $count failed';
+  }
+
+  @override
+  String get settingsSaveDownloadHistory => 'Save download history';
+
+  @override
+  String get settingsSaveDownloadHistorySubtitle =>
+      'Keep completed downloads in history and library views';
+
+  @override
+  String get dialogDisableHistoryTitle => 'Turn off download history?';
+
+  @override
+  String get dialogDisableHistoryMessage =>
+      'Existing history will be cleared. Downloaded files will not be deleted.';
+
+  @override
+  String get dialogDisableAndClear => 'Turn off and clear';
+
+  @override
+  String get openInOtherServices => 'Open in Other Services';
+
+  @override
+  String get shareSheetNoExtensions => 'No other compatible services';
+
+  @override
+  String get shareSheetNotFound => 'Not found';
+
+  @override
+  String get shareSheetCopyLink => 'Copy Link';
+
+  @override
+  String shareSheetLinkCopied(Object service) {
+    return '$service link copied';
+  }
 }

lib/l10n/app_localizations_ja.dart

@@ -126,7 +126,7 @@ class AppLocalizationsJa extends AppLocalizations {
 
   @override
   String get optionsPrimaryProviderSubtitle =>
-      'Service used when searching by track name.';
+      'Service used for searching by track or album name';
 
   @override
   String optionsUsingExtension(String extensionName) {
@@ -142,7 +142,7 @@ class AppLocalizationsJa extends AppLocalizations {
 
   @override
   String get optionsSwitchBack =>
-      'Tap Deezer or Spotify to switch back from extension';
+      'Choose the default search provider to switch back from an extension';
 
   @override
   String get optionsAutoFallback => 'Auto Fallback';
@@ -155,16 +155,19 @@ class AppLocalizationsJa extends AppLocalizations {
   String get optionsUseExtensionProviders => '拡張のプロバイダーを使用する';
 
   @override
-  String get optionsUseExtensionProvidersOn => '最初に拡張で試みます';
+  String get optionsUseExtensionProvidersOn =>
+      'Extension providers are enabled';
 
   @override
-  String get optionsUseExtensionProvidersOff => '内蔵のプロバイダーのみを使用する';
+  String get optionsUseExtensionProvidersOff =>
+      'Extension providers are required';
 
   @override
   String get optionsEmbedLyrics => '歌詞を埋め込む';
 
   @override
-  String get optionsEmbedLyricsSubtitle => '同期する歌詞を FLAC ファイルに埋め込む';
+  String get optionsEmbedLyricsSubtitle =>
+      'Save synced lyrics alongside your downloaded tracks';
 
   @override
   String get optionsMaxQualityCover => '最大品質のカバー';
@@ -183,6 +186,43 @@ class AppLocalizationsJa extends AppLocalizations {
   String get optionsReplayGainSubtitleOff =>
       'Disabled: no loudness normalization tags';
 
+  @override
+  String get trackReplayGain => 'Rescan ReplayGain';
+
+  @override
+  String get trackReplayGainSubtitle =>
+      'Analyze loudness and write ReplayGain tags';
+
+  @override
+  String get trackReplayGainScanning => 'Analyzing loudness...';
+
+  @override
+  String get trackReplayGainSuccess => 'ReplayGain tags added';
+
+  @override
+  String get trackReplayGainFailed => 'Failed to add ReplayGain tags';
+
+  @override
+  String selectionReplayGainCount(int count) {
+    return 'ReplayGain ($count)';
+  }
+
+  @override
+  String get replayGainBatchConfirmTitle => 'Add ReplayGain';
+
+  @override
+  String replayGainBatchConfirmMessage(int count) {
+    return 'Analyze loudness and write ReplayGain tags to $count track(s)?';
+  }
+
+  @override
+  String get replayGainBatchAnalyzing => 'Analyzing ReplayGain...';
+
+  @override
+  String replayGainBatchSuccess(int success, int total) {
+    return 'ReplayGain added to $success of $total tracks';
+  }
+
   @override
   String get optionsArtistTagMode => 'Artist Tag Mode';
 
@@ -204,21 +244,6 @@ class AppLocalizationsJa extends AppLocalizations {
   String get optionsArtistTagModeSplitVorbisSubtitle =>
       'Write one artist tag per artist for FLAC and Opus; MP3 and M4A stay joined.';
 
-  @override
-  String get optionsConcurrentDownloads => '同時ダウンロード';
-
-  @override
-  String get optionsConcurrentSequential => 'Sequential (1 at a time)';
-
-  @override
-  String optionsConcurrentParallel(int count) {
-    return '$count 件の分割ダウンロード';
-  }
-
-  @override
-  String get optionsConcurrentWarning =>
-      'Parallel downloads may trigger rate limiting';
-
   @override
   String get optionsExtensionStore => 'Extension Repo';
 
@@ -381,11 +406,11 @@ class AppLocalizationsJa extends AppLocalizations {
 
   @override
   String get aboutBinimumDesc =>
-      'The creator of QQDL & HiFi API. Without this API, Tidal downloads wouldn\'t exist!';
+      'The creator of QQDL & HiFi API. This project helped shape lossless download support.';
 
   @override
   String get aboutSachinsenalDesc =>
-      'The original HiFi project creator. The foundation of Tidal integration!';
+      'The original HiFi project creator. A foundation for lossless-source integration.';
 
   @override
   String get aboutSjdonadoDesc =>
@@ -393,7 +418,7 @@ class AppLocalizationsJa extends AppLocalizations {
 
   @override
   String get aboutAppDescription =>
-      'Download Spotify tracks in lossless quality from Tidal and Qobuz.';
+      'Search music metadata, manage extensions, and organize your library.';
 
   @override
   String get artistAlbums => 'アルバム';
@@ -737,6 +762,9 @@ class AppLocalizationsJa extends AppLocalizations {
   @override
   String get errorNoTracksFound => 'トラックがありません';
 
+  @override
+  String get searchEmptyResultSubtitle => 'Try another keyword';
+
   @override
   String get errorUrlNotRecognized => 'Link not recognized';
 
@@ -944,7 +972,7 @@ class AppLocalizationsJa extends AppLocalizations {
       'Only enabled extensions with download-provider capability are listed here.';
 
   @override
-  String get providerBuiltIn => '内蔵';
+  String get providerBuiltIn => 'Legacy';
 
   @override
   String get providerExtension => '拡張';
@@ -1112,10 +1140,10 @@ class AppLocalizationsJa extends AppLocalizations {
   String get settingsAppearanceSubtitle => 'テーマ、カラー、画面';
 
   @override
-  String get settingsDownloadSubtitle => 'サービス、品質、ファイル名、形式';
+  String get settingsDownloadSubtitle => 'Service, quality, fallback';
 
   @override
-  String get settingsOptionsSubtitle => 'Fallback, lyrics, cover art, updates';
+  String get settingsOptionsSubtitle => 'Fallback, metadata, lyrics, cover art';
 
   @override
   String get settingsExtensionsSubtitle => 'ダウンロードプロバイダーを管理';
@@ -1214,6 +1242,11 @@ class AppLocalizationsJa extends AppLocalizations {
   @override
   String get trackCopyLyrics => '歌詞をコピー';
 
+  @override
+  String trackLyricsSource(String source) {
+    return 'Source: $source';
+  }
+
   @override
   String get trackLyricsNotAvailable => 'このトラックの歌詞は利用できません';
 
@@ -1332,10 +1365,11 @@ class AppLocalizationsJa extends AppLocalizations {
   String get storeEmptyNoResults => 'No extensions found';
 
   @override
-  String get extensionDefaultProvider => 'Default (Deezer)';
+  String get extensionDefaultProvider => 'Default Search';
 
   @override
-  String get extensionDefaultProviderSubtitle => '内蔵の検索を使用する';
+  String get extensionDefaultProviderSubtitle =>
+      'Use the default metadata search';
 
   @override
   String get extensionAuthor => '作者';
@@ -1505,7 +1539,7 @@ class AppLocalizationsJa extends AppLocalizations {
 
   @override
   String get downloadLossy320FormatDesc =>
-      'Choose the output format for Tidal 320kbps lossy downloads. The original AAC stream will be converted to your selected format.';
+      'Choose the output format for 320kbps lossy downloads. The original stream will be converted to your selected format when needed.';
 
   @override
   String get downloadLossyMp3 => 'MP3 320kbps';
@@ -1513,6 +1547,13 @@ class AppLocalizationsJa extends AppLocalizations {
   @override
   String get downloadLossyMp3Subtitle => 'Best compatibility, ~10MB per track';
 
+  @override
+  String get downloadLossyAac => 'AAC/M4A 320kbps';
+
+  @override
+  String get downloadLossyAacSubtitle =>
+      'Best mobile compatibility, M4A container';
+
   @override
   String get downloadLossyOpus256 => 'Opus 256kbps';
 
@@ -2065,7 +2106,7 @@ class AppLocalizationsJa extends AppLocalizations {
 
   @override
   String get tutorialWelcomeTip2 =>
-      'Get FLAC quality audio from Tidal, Qobuz, or Deezer';
+      'Get FLAC quality audio from installed download extensions';
 
   @override
   String get tutorialWelcomeTip3 =>
@@ -2395,7 +2436,7 @@ class AppLocalizationsJa extends AppLocalizations {
 
   @override
   String get trackConvertFormatSubtitle =>
-      'Convert to MP3, Opus, ALAC, or FLAC';
+      'Convert to AAC/M4A, MP3, Opus, ALAC, or FLAC';
 
   @override
   String get trackConvertTitle => 'オーディオを変換';
@@ -2748,14 +2789,14 @@ class AppLocalizationsJa extends AppLocalizations {
 
   @override
   String get downloadUseAlbumArtistForFoldersAlbumSubtitle =>
-      'Artist folders use Album Artist when available';
+      'Folder named after Album Artist tag';
 
   @override
   String get downloadUseAlbumArtistForFoldersTrackSubtitle =>
-      'Artist folders use Track Artist only';
+      'Folder named after Track Artist tag';
 
   @override
-  String get lyricsProvidersTitle => 'Lyrics Providers';
+  String get lyricsProvidersTitle => 'Lyrics Provider Priority';
 
   @override
   String get lyricsProvidersDescription =>
@@ -2763,7 +2804,7 @@ class AppLocalizationsJa extends AppLocalizations {
 
   @override
   String get lyricsProvidersInfoText =>
-      'Extension lyrics providers always run before built-in providers. At least one provider must remain enabled.';
+      'Extension lyrics providers run before built-in lyrics providers. At least one provider must remain enabled.';
 
   @override
   String lyricsProvidersEnabledSection(int count) {
@@ -2805,6 +2846,10 @@ class AppLocalizationsJa extends AppLocalizations {
   String get lyricsProviderQqMusicDesc =>
       'QQ Music (good for Chinese songs, via proxy)';
 
+  @override
+  String get lyricsProviderLyricsPlusDesc =>
+      'Word-by-word karaoke lyrics (Apple/Musixmatch/Spotify/QQ, via proxy)';
+
   @override
   String get lyricsProviderExtensionDesc => 'Extension provider';
 
@@ -2823,10 +2868,10 @@ class AppLocalizationsJa extends AppLocalizations {
   String get safMigrationSuccess => 'Download folder updated to SAF mode';
 
   @override
-  String get settingsDonate => 'Donate';
+  String get settingsDonate => 'Support Development';
 
   @override
-  String get settingsDonateSubtitle => 'Support SpotiFLAC-Mobile development';
+  String get settingsDonateSubtitle => 'Buy the developer a coffee';
 
   @override
   String get tooltipLoveAll => 'Love All';
@@ -2886,20 +2931,20 @@ class AppLocalizationsJa extends AppLocalizations {
 
   @override
   String get downloadLocationSubtitle =>
-      'Choose storage mode for downloaded files.';
+      'Choose where to save your downloaded tracks';
 
   @override
-  String get storageModeAppFolder => 'App folder (non-SAF)';
+  String get storageModeAppFolder => 'App Folder (Recommended)';
 
   @override
-  String get storageModeAppFolderSubtitle => 'Use default Music/SpotiFLAC path';
+  String get storageModeAppFolderSubtitle =>
+      'Saves to Music/SpotiFLAC by default';
 
   @override
-  String get storageModeSaf => 'SAF folder';
+  String get storageModeSaf => 'Custom Folder (SAF)';
 
   @override
-  String get storageModeSafSubtitle =>
-      'Pick folder via Android Storage Access Framework';
+  String get storageModeSafSubtitle => 'Pick any folder, including SD card';
 
   @override
   String downloadFilenameDescription(
@@ -2911,62 +2956,62 @@ class AppLocalizationsJa extends AppLocalizations {
     Object track,
     Object year,
   ) {
-    return 'Customize how your files are named.';
+    return 'Use $artist, $title, $album, $track, $year, $date, $disc as placeholders.';
   }
 
   @override
   String get downloadFilenameInsertTag => 'Tap to insert tag:';
 
   @override
-  String get downloadSeparateSinglesEnabled => 'Albums/ and Singles/ folders';
+  String get downloadSeparateSinglesEnabled =>
+      'Singles and EPs saved in a separate folder';
 
   @override
-  String get downloadSeparateSinglesDisabled => 'All files in same structure';
+  String get downloadSeparateSinglesDisabled =>
+      'Singles and albums saved in the same folder';
 
   @override
   String get downloadArtistNameFilters => 'Artist Name Filters';
 
   @override
-  String get downloadCreatePlaylistSourceFolder =>
-      'Create playlist source folder';
+  String get downloadCreatePlaylistSourceFolder => 'Playlist Source Folder';
 
   @override
   String get downloadCreatePlaylistSourceFolderEnabled =>
-      'Playlist downloads use Playlist/ plus your normal folder structure.';
+      'A subfolder is created for each playlist';
 
   @override
   String get downloadCreatePlaylistSourceFolderDisabled =>
-      'Playlist downloads use the normal folder structure only.';
+      'All tracks saved directly to download folder';
 
   @override
   String get downloadCreatePlaylistSourceFolderRedundant =>
-      'By Playlist already places downloads inside a playlist folder.';
+      'Handled by folder organization setting';
 
   @override
   String get downloadSongLinkRegion => 'SongLink Region';
 
   @override
-  String get downloadNetworkCompatibilityMode => 'Network compatibility mode';
+  String get downloadNetworkCompatibilityMode => 'Network Compatibility Mode';
 
   @override
   String get downloadNetworkCompatibilityModeEnabled =>
-      'Enabled: try HTTP + accept invalid TLS certificates (unsafe)';
+      'Using legacy TLS settings for older networks';
 
   @override
   String get downloadNetworkCompatibilityModeDisabled =>
-      'Off: strict HTTPS certificate validation (recommended)';
+      'Using standard network settings';
 
   @override
   String get downloadSelectServiceToEnable =>
-      'Select a built-in service to enable';
+      'Select a provider with quality options to enable this option';
 
   @override
   String get downloadSelectTidalQobuz =>
-      'Select Tidal or Qobuz above to configure quality';
+      'Select a provider with quality options to choose audio quality';
 
   @override
-  String get downloadEmbedLyricsDisabled =>
-      'Disabled while Embed Metadata is turned off';
+  String get downloadEmbedLyricsDisabled => 'Enable metadata embedding first';
 
   @override
   String get downloadNeteaseIncludeTranslation =>
@@ -2974,11 +3019,11 @@ class AppLocalizationsJa extends AppLocalizations {
 
   @override
   String get downloadNeteaseIncludeTranslationEnabled =>
-      'Append translated lyrics when available';
+      'Chinese translation lines included';
 
   @override
   String get downloadNeteaseIncludeTranslationDisabled =>
-      'Use original lyrics only';
+      'Original lyrics only';
 
   @override
   String get downloadNeteaseIncludeRomanization =>
@@ -2986,66 +3031,76 @@ class AppLocalizationsJa extends AppLocalizations {
 
   @override
   String get downloadNeteaseIncludeRomanizationEnabled =>
-      'Append romanized lyrics when available';
+      'Romanization lines included';
 
   @override
-  String get downloadNeteaseIncludeRomanizationDisabled => 'Disabled';
+  String get downloadNeteaseIncludeRomanizationDisabled => 'No romanization';
 
   @override
-  String get downloadAppleQqMultiPerson => 'Apple/QQ Multi-Person Word-by-Word';
+  String get downloadAppleQqMultiPerson => 'Apple / QQ: Multi-Person Lyrics';
 
   @override
   String get downloadAppleQqMultiPersonEnabled =>
-      'Enable v1/v2 speaker and [bg:] tags';
+      'Speaker labels included for duets and group tracks';
 
   @override
   String get downloadAppleQqMultiPersonDisabled =>
-      'Simplified word-by-word formatting';
+      'Standard lyrics without speaker labels';
+
+  @override
+  String get downloadAppleElrcWordSync => 'Apple Music eLRC Word Sync';
+
+  @override
+  String get downloadAppleElrcWordSyncEnabled =>
+      'Raw word-by-word timestamps preserved';
+
+  @override
+  String get downloadAppleElrcWordSyncDisabled =>
+      'Safer line-by-line Apple Music lyrics';
 
   @override
   String get downloadMusixmatchLanguage => 'Musixmatch Language';
 
   @override
-  String get downloadMusixmatchLanguageAuto => 'Auto (original)';
+  String get downloadMusixmatchLanguageAuto => 'Auto (original language)';
 
   @override
-  String get downloadFilterContributing =>
-      'Filter contributing artists in Album Artist';
+  String get downloadFilterContributing => 'Filter Contributing Artists';
 
   @override
   String get downloadFilterContributingEnabled =>
-      'Album Artist metadata uses primary artist only';
+      'Contributing artists removed from Album Artist folder name';
 
   @override
   String get downloadFilterContributingDisabled =>
-      'Keep full Album Artist metadata value';
+      'Full Album Artist string used';
 
   @override
-  String get downloadProvidersNoneEnabled => 'None enabled';
+  String get downloadProvidersNoneEnabled => 'No providers enabled';
 
   @override
   String get downloadMusixmatchLanguageCode => 'Language code';
 
   @override
-  String get downloadMusixmatchLanguageHint => 'auto / en / es / ja';
+  String get downloadMusixmatchLanguageHint => 'e.g. en, de, ja';
 
   @override
   String get downloadMusixmatchLanguageDesc =>
-      'Set preferred language code (example: en, es, ja). Leave empty for auto.';
+      'Enter a BCP-47 language code (e.g. en, de, ja) to request translated lyrics from Musixmatch.';
 
   @override
   String get downloadMusixmatchAuto => 'Auto';
 
   @override
-  String get downloadNetworkAnySubtitle => 'WiFi + Mobile Data';
+  String get downloadNetworkAnySubtitle => 'Use WiFi or mobile data';
 
   @override
   String get downloadNetworkWifiOnlySubtitle =>
-      'Pause downloads on mobile data';
+      'Downloads pause when on mobile data';
 
   @override
   String get downloadSongLinkRegionDesc =>
-      'Used as userCountry for SongLink API lookup.';
+      'Region used when resolving track links via SongLink. Choose the country where your streaming services are available.';
 
   @override
   String get snackbarUnsupportedAudioFormat => 'Unsupported audio format';
@@ -3248,6 +3303,15 @@ class AppLocalizationsJa extends AppLocalizations {
   @override
   String get audioAnalysisSampleRate => 'Sample Rate';
 
+  @override
+  String get audioAnalysisCodec => 'Codec';
+
+  @override
+  String get audioAnalysisContainer => 'Container';
+
+  @override
+  String get audioAnalysisDecodedFormat => 'Decoded Format';
+
   @override
   String get audioAnalysisBitDepth => 'Bit Depth';
 
@@ -3272,9 +3336,33 @@ class AppLocalizationsJa extends AppLocalizations {
   @override
   String get audioAnalysisRms => 'RMS';
 
+  @override
+  String get audioAnalysisLufs => 'LUFS';
+
+  @override
+  String get audioAnalysisTruePeak => 'True Peak';
+
+  @override
+  String get audioAnalysisClipping => 'Clipping';
+
+  @override
+  String get audioAnalysisNoClipping => 'No clipping';
+
+  @override
+  String get audioAnalysisSpectralCutoff => 'Spectral Cutoff';
+
+  @override
+  String get audioAnalysisChannelStats => 'Per-channel Stats';
+
   @override
   String get audioAnalysisSamples => 'Samples';
 
+  @override
+  String get audioAnalysisRescan => 'Re-analyze';
+
+  @override
+  String get audioAnalysisRescanning => 'Re-analyzing audio...';
+
   @override
   String extensionsSearchWith(String providerName) {
     return 'Search with $providerName';
@@ -3398,7 +3486,13 @@ class AppLocalizationsJa extends AppLocalizations {
 
   @override
   String notifTracksDownloadedSuccess(int count) {
-    return '$count tracks downloaded successfully';
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: '$count tracks downloaded successfully',
+      one: '1 track downloaded successfully',
+    );
+    return '$_temp0';
   }
 
   @override
@@ -3593,6 +3687,13 @@ class AppLocalizationsJa extends AppLocalizations {
   @override
   String get queueDownloadCompleted => 'Download completed';
 
+  @override
+  String get queueRateLimitTitle => 'Service rate limited';
+
+  @override
+  String get queueRateLimitMessage =>
+      'This track may still be available. Wait a few minutes, reduce parallel downloads, then retry.';
+
   @override
   String appearanceSelectAccentColor(String hex) {
     return 'Select accent color $hex';
@@ -3786,4 +3887,379 @@ class AppLocalizationsJa extends AppLocalizations {
   @override
   String get downloadFallbackExtensionsSubtitle =>
       'Choose which extensions can be used as fallback';
+
+  @override
+  String get editMetadataFieldDateHint => 'YYYY-MM-DD or YYYY';
+
+  @override
+  String get editMetadataFieldTrackTotal => 'Track Total';
+
+  @override
+  String get editMetadataFieldDiscTotal => 'Disc Total';
+
+  @override
+  String get editMetadataFieldComposer => 'Composer';
+
+  @override
+  String get editMetadataFieldComment => 'Comment';
+
+  @override
+  String get editMetadataAdvanced => 'Advanced';
+
+  @override
+  String get libraryFilterMetadataMissingTrackNumber => 'Missing track number';
+
+  @override
+  String get libraryFilterMetadataMissingDiscNumber => 'Missing disc number';
+
+  @override
+  String get libraryFilterMetadataMissingArtist => 'Missing artist';
+
+  @override
+  String get libraryFilterMetadataIncorrectIsrcFormat =>
+      'Incorrect ISRC format';
+
+  @override
+  String get libraryFilterMetadataMissingLabel => 'Missing label';
+
+  @override
+  String collectionDeletePlaylistsMessage(int count) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'playlists',
+      one: 'playlist',
+    );
+    return 'Delete $count $_temp0?';
+  }
+
+  @override
+  String collectionPlaylistsDeleted(int count) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'playlists',
+      one: 'playlist',
+    );
+    return '$count $_temp0 deleted';
+  }
+
+  @override
+  String collectionAddedTracksToPlaylist(int count, String playlistName) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'tracks',
+      one: 'track',
+    );
+    return 'Added $count $_temp0 to $playlistName';
+  }
+
+  @override
+  String collectionAddedTracksToPlaylistWithExisting(
+    int count,
+    String playlistName,
+    int alreadyCount,
+  ) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'tracks',
+      one: 'track',
+    );
+    return 'Added $count $_temp0 to $playlistName ($alreadyCount already in playlist)';
+  }
+
+  @override
+  String itemCount(int count) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'items',
+      one: 'item',
+    );
+    return '$count $_temp0';
+  }
+
+  @override
+  String trackReEnrichSuccessWithFailures(
+    int successCount,
+    int total,
+    int failedCount,
+  ) {
+    return 'Metadata re-enriched successfully ($successCount/$total) - Failed: $failedCount';
+  }
+
+  @override
+  String selectionDeleteTracksCount(int count) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'tracks',
+      one: 'track',
+    );
+    return 'Delete $count $_temp0';
+  }
+
+  @override
+  String queueDownloadSpeedStatus(String speed) {
+    return 'Downloading - $speed MB/s';
+  }
+
+  @override
+  String get queueDownloadStarting => 'Starting...';
+
+  @override
+  String get a11ySelectTrack => 'Select track';
+
+  @override
+  String get a11yDeselectTrack => 'Deselect track';
+
+  @override
+  String a11yPlayTrackByArtist(String trackName, String artistName) {
+    return 'Play $trackName by $artistName';
+  }
+
+  @override
+  String storeExtensionsCount(int count) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'extensions',
+      one: 'extension',
+    );
+    return '$count $_temp0';
+  }
+
+  @override
+  String storeRequiresVersion(String version) {
+    return 'Requires v$version+';
+  }
+
+  @override
+  String get actionGo => 'Go';
+
+  @override
+  String get logIssueSummary => 'Issue Summary';
+
+  @override
+  String logTotalErrors(int count) {
+    return 'Total errors: $count';
+  }
+
+  @override
+  String logAffectedDomains(String domains) {
+    return 'Affected: $domains';
+  }
+
+  @override
+  String get libraryScanCancelled => 'Scan cancelled';
+
+  @override
+  String get libraryScanCancelledSubtitle =>
+      'You can retry the scan when ready.';
+
+  @override
+  String libraryDownloadsHistoryExcluded(int count) {
+    return '$count from Downloads history (excluded from list)';
+  }
+
+  @override
+  String get downloadNativeWorker => 'Native download worker';
+
+  @override
+  String get downloadNativeWorkerSubtitle =>
+      'Beta Android service worker for extension downloads';
+
+  @override
+  String get badgeBeta => 'BETA';
+
+  @override
+  String get extensionServiceStatus => 'Service Status';
+
+  @override
+  String get extensionServiceHealth => 'Service health';
+
+  @override
+  String extensionHealthChecksConfigured(int count) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'checks',
+      one: 'check',
+    );
+    return '$count $_temp0 configured';
+  }
+
+  @override
+  String get extensionOauthConnectHint =>
+      'Tap Connect to Spotify to fill this field.';
+
+  @override
+  String extensionLastChecked(String time) {
+    return 'Last checked $time';
+  }
+
+  @override
+  String get extensionRefreshStatus => 'Refresh status';
+
+  @override
+  String get extensionCustomUrlHandling => 'Custom URL Handling';
+
+  @override
+  String get extensionCustomUrlHandlingSubtitle =>
+      'This extension can handle links from these sites';
+
+  @override
+  String get extensionCustomUrlHandlingShareHint =>
+      'Share links from these sites to SpotiFLAC Mobile and this extension will handle them.';
+
+  @override
+  String extensionSettingsCount(int count) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'settings',
+      one: 'setting',
+    );
+    return '$count $_temp0';
+  }
+
+  @override
+  String get extensionHealthOnline => 'Online';
+
+  @override
+  String get extensionHealthDegraded => 'Degraded';
+
+  @override
+  String get extensionHealthOffline => 'Offline';
+
+  @override
+  String get extensionHealthNotConfigured => 'Not configured';
+
+  @override
+  String get extensionHealthUnknown => 'Unknown';
+
+  @override
+  String get extensionHealthRequired => 'required';
+
+  @override
+  String get extensionSettingNotSet => 'Not set';
+
+  @override
+  String get extensionActionFailed => 'Action failed';
+
+  @override
+  String get extensionEnterValue => 'Enter value';
+
+  @override
+  String get extensionHealthServiceOnline => 'Service online';
+
+  @override
+  String get extensionHealthServiceDegraded => 'Service degraded';
+
+  @override
+  String get extensionHealthServiceOffline => 'Service offline';
+
+  @override
+  String get extensionHealthServiceUnknown => 'Service status unknown';
+
+  @override
+  String get audioAnalysisStereo => 'Stereo';
+
+  @override
+  String get audioAnalysisMono => 'Mono';
+
+  @override
+  String trackOpenInService(String serviceName) {
+    return 'Open in $serviceName';
+  }
+
+  @override
+  String get trackLyricsEmbeddedSource => 'Embedded';
+
+  @override
+  String get unknownAlbum => 'Unknown Album';
+
+  @override
+  String get unknownArtist => 'Unknown Artist';
+
+  @override
+  String get permissionAudio => 'Audio';
+
+  @override
+  String get permissionStorage => 'Storage';
+
+  @override
+  String get permissionNotification => 'Notification';
+
+  @override
+  String get errorInvalidFolderSelected => 'Invalid folder selected';
+
+  @override
+  String get errorCouldNotKeepFolderAccess =>
+      'Could not keep access to the selected folder';
+
+  @override
+  String get storeAnyVersion => 'Any';
+
+  @override
+  String get storeCategoryMetadata => 'Metadata';
+
+  @override
+  String get storeCategoryDownload => 'Download';
+
+  @override
+  String get storeCategoryUtility => 'Utility';
+
+  @override
+  String get storeCategoryLyrics => 'Lyrics';
+
+  @override
+  String get storeCategoryIntegration => 'Integration';
+
+  @override
+  String get artistReleases => 'Releases';
+
+  @override
+  String get editMetadataSelectNone => 'None';
+
+  @override
+  String queueRetryAllFailed(int count) {
+    return 'Retry $count failed';
+  }
+
+  @override
+  String get settingsSaveDownloadHistory => 'Save download history';
+
+  @override
+  String get settingsSaveDownloadHistorySubtitle =>
+      'Keep completed downloads in history and library views';
+
+  @override
+  String get dialogDisableHistoryTitle => 'Turn off download history?';
+
+  @override
+  String get dialogDisableHistoryMessage =>
+      'Existing history will be cleared. Downloaded files will not be deleted.';
+
+  @override
+  String get dialogDisableAndClear => 'Turn off and clear';
+
+  @override
+  String get openInOtherServices => 'Open in Other Services';
+
+  @override
+  String get shareSheetNoExtensions => 'No other compatible services';
+
+  @override
+  String get shareSheetNotFound => 'Not found';
+
+  @override
+  String get shareSheetCopyLink => 'Copy Link';
+
+  @override
+  String shareSheetLinkCopied(Object service) {
+    return '$service link copied';
+  }
 }

lib/l10n/app_localizations_ko.dart

@@ -27,7 +27,7 @@ class AppLocalizationsKo extends AppLocalizations {
   String get homeTitle => 'Home';
 
   @override
-  String get homeSubtitle => 'Paste a supported URL or search by name';
+  String get homeSubtitle => '지원되는 URL을 붙여 넣거나, 이름을 검색';
 
   @override
   String get homeEmptyTitle => 'No search providers yet';
@@ -97,10 +97,10 @@ class AppLocalizationsKo extends AppLocalizations {
   String get appearanceThemeSystem => 'System';
 
   @override
-  String get appearanceThemeLight => 'Light';
+  String get appearanceThemeLight => '밝은';
 
   @override
-  String get appearanceThemeDark => 'Dark';
+  String get appearanceThemeDark => '다크';
 
   @override
   String get appearanceDynamicColor => 'Dynamic Color';
@@ -124,7 +124,8 @@ class AppLocalizationsKo extends AppLocalizations {
   String get optionsPrimaryProvider => '기본 제공자';
 
   @override
-  String get optionsPrimaryProviderSubtitle => '음반 이름으로 검색할 때 사용되는 서비스';
+  String get optionsPrimaryProviderSubtitle =>
+      'Service used for searching by track or album name';
 
   @override
   String optionsUsingExtension(String extensionName) {
@@ -139,7 +140,8 @@ class AppLocalizationsKo extends AppLocalizations {
       'Choose which tab opens first for new search results.';
 
   @override
-  String get optionsSwitchBack => 'Deezer 또는 Spotify를 탭하여 확장 기능에서 다시 전환하세요.';
+  String get optionsSwitchBack =>
+      'Choose the default search provider to switch back from an extension';
 
   @override
   String get optionsAutoFallback => '자동 재시도';
@@ -151,16 +153,19 @@ class AppLocalizationsKo extends AppLocalizations {
   String get optionsUseExtensionProviders => '확장 기능 사용';
 
   @override
-  String get optionsUseExtensionProvidersOn => '확장 기능을 우선적으로 사용합니다';
+  String get optionsUseExtensionProvidersOn =>
+      'Extension providers are enabled';
 
   @override
-  String get optionsUseExtensionProvidersOff => '기본으로 제공되는 기능만 사용';
+  String get optionsUseExtensionProvidersOff =>
+      'Extension providers are required';
 
   @override
   String get optionsEmbedLyrics => '가사 삽입';
 
   @override
-  String get optionsEmbedLyricsSubtitle => 'FLAC 파일에 동기화된 가사를 삽입합니다';
+  String get optionsEmbedLyricsSubtitle =>
+      'Save synced lyrics alongside your downloaded tracks';
 
   @override
   String get optionsMaxQualityCover => '고품질 커버 이미지';
@@ -179,6 +184,43 @@ class AppLocalizationsKo extends AppLocalizations {
   String get optionsReplayGainSubtitleOff =>
       'Disabled: no loudness normalization tags';
 
+  @override
+  String get trackReplayGain => 'Rescan ReplayGain';
+
+  @override
+  String get trackReplayGainSubtitle =>
+      'Analyze loudness and write ReplayGain tags';
+
+  @override
+  String get trackReplayGainScanning => 'Analyzing loudness...';
+
+  @override
+  String get trackReplayGainSuccess => 'ReplayGain tags added';
+
+  @override
+  String get trackReplayGainFailed => 'Failed to add ReplayGain tags';
+
+  @override
+  String selectionReplayGainCount(int count) {
+    return 'ReplayGain ($count)';
+  }
+
+  @override
+  String get replayGainBatchConfirmTitle => 'Add ReplayGain';
+
+  @override
+  String replayGainBatchConfirmMessage(int count) {
+    return 'Analyze loudness and write ReplayGain tags to $count track(s)?';
+  }
+
+  @override
+  String get replayGainBatchAnalyzing => 'Analyzing ReplayGain...';
+
+  @override
+  String replayGainBatchSuccess(int success, int total) {
+    return 'ReplayGain added to $success of $total tracks';
+  }
+
   @override
   String get optionsArtistTagMode => 'Artist Tag Mode';
 
@@ -200,20 +242,6 @@ class AppLocalizationsKo extends AppLocalizations {
   String get optionsArtistTagModeSplitVorbisSubtitle =>
       'Write one artist tag per artist for FLAC and Opus; MP3 and M4A stay joined.';
 
-  @override
-  String get optionsConcurrentDownloads => '동시 다운로드';
-
-  @override
-  String get optionsConcurrentSequential => '순차 다운로드 (한 번에 하나)';
-
-  @override
-  String optionsConcurrentParallel(int count) {
-    return '$count개 동시 다운로드';
-  }
-
-  @override
-  String get optionsConcurrentWarning => '동시에 다수의 음반을 다운로드하면 속도 제한이 발생할 수 있습니다';
-
   @override
   String get optionsExtensionStore => 'Extension Repo';
 
@@ -374,10 +402,11 @@ class AppLocalizationsKo extends AppLocalizations {
 
   @override
   String get aboutBinimumDesc =>
-      'QQDL 및 HiFi API 개발자입니다. 이 API가 없었다면 Tidal 다운로드는 불가능했을 것입니다!';
+      'The creator of QQDL & HiFi API. This project helped shape lossless download support.';
 
   @override
-  String get aboutSachinsenalDesc => '최초의 하이파이 프로젝트 창시자. 타이달 연동의 기반을 마련한 사람!';
+  String get aboutSachinsenalDesc =>
+      'The original HiFi project creator. A foundation for lossless-source integration.';
 
   @override
   String get aboutSjdonadoDesc =>
@@ -385,7 +414,7 @@ class AppLocalizationsKo extends AppLocalizations {
 
   @override
   String get aboutAppDescription =>
-      'Download Spotify tracks in lossless quality from Tidal and Qobuz.';
+      'Search music metadata, manage extensions, and organize your library.';
 
   @override
   String get artistAlbums => '앨범';
@@ -724,6 +753,9 @@ class AppLocalizationsKo extends AppLocalizations {
   @override
   String get errorNoTracksFound => '트랙을 찾을 수 없습니다';
 
+  @override
+  String get searchEmptyResultSubtitle => 'Try another keyword';
+
   @override
   String get errorUrlNotRecognized => 'Link not recognized';
 
@@ -826,7 +858,7 @@ class AppLocalizationsKo extends AppLocalizations {
   String get tooltipPlay => '재생';
 
   @override
-  String get filenameFormat => '';
+  String get filenameFormat => 'Filename Format';
 
   @override
   String get filenameShowAdvancedTags => '고급 태그 표시';
@@ -932,7 +964,7 @@ class AppLocalizationsKo extends AppLocalizations {
       'Only enabled extensions with download-provider capability are listed here.';
 
   @override
-  String get providerBuiltIn => 'Built-in';
+  String get providerBuiltIn => 'Legacy';
 
   @override
   String get providerExtension => 'Extension';
@@ -1098,10 +1130,10 @@ class AppLocalizationsKo extends AppLocalizations {
   String get settingsAppearanceSubtitle => 'Theme, colors, display';
 
   @override
-  String get settingsDownloadSubtitle => 'Service, quality, filename format';
+  String get settingsDownloadSubtitle => 'Service, quality, fallback';
 
   @override
-  String get settingsOptionsSubtitle => 'Fallback, lyrics, cover art, updates';
+  String get settingsOptionsSubtitle => 'Fallback, metadata, lyrics, cover art';
 
   @override
   String get settingsExtensionsSubtitle => 'Manage download providers';
@@ -1200,6 +1232,11 @@ class AppLocalizationsKo extends AppLocalizations {
   @override
   String get trackCopyLyrics => 'Copy lyrics';
 
+  @override
+  String trackLyricsSource(String source) {
+    return 'Source: $source';
+  }
+
   @override
   String get trackLyricsNotAvailable => 'Lyrics not available for this track';
 
@@ -1318,10 +1355,11 @@ class AppLocalizationsKo extends AppLocalizations {
   String get storeEmptyNoResults => 'No extensions found';
 
   @override
-  String get extensionDefaultProvider => 'Default (Deezer)';
+  String get extensionDefaultProvider => 'Default Search';
 
   @override
-  String get extensionDefaultProviderSubtitle => 'Use built-in search';
+  String get extensionDefaultProviderSubtitle =>
+      'Use the default metadata search';
 
   @override
   String get extensionAuthor => 'Author';
@@ -1495,7 +1533,7 @@ class AppLocalizationsKo extends AppLocalizations {
 
   @override
   String get downloadLossy320FormatDesc =>
-      'Choose the output format for Tidal 320kbps lossy downloads. The original AAC stream will be converted to your selected format.';
+      'Choose the output format for 320kbps lossy downloads. The original stream will be converted to your selected format when needed.';
 
   @override
   String get downloadLossyMp3 => 'MP3 320kbps';
@@ -1503,6 +1541,13 @@ class AppLocalizationsKo extends AppLocalizations {
   @override
   String get downloadLossyMp3Subtitle => 'Best compatibility, ~10MB per track';
 
+  @override
+  String get downloadLossyAac => 'AAC/M4A 320kbps';
+
+  @override
+  String get downloadLossyAacSubtitle =>
+      'Best mobile compatibility, M4A container';
+
   @override
   String get downloadLossyOpus256 => 'Opus 256kbps';
 
@@ -2058,7 +2103,7 @@ class AppLocalizationsKo extends AppLocalizations {
 
   @override
   String get tutorialWelcomeTip2 =>
-      'Get FLAC quality audio from Tidal, Qobuz, or Deezer';
+      'Get FLAC quality audio from installed download extensions';
 
   @override
   String get tutorialWelcomeTip3 =>
@@ -2388,7 +2433,7 @@ class AppLocalizationsKo extends AppLocalizations {
 
   @override
   String get trackConvertFormatSubtitle =>
-      'Convert to MP3, Opus, ALAC, or FLAC';
+      'Convert to AAC/M4A, MP3, Opus, ALAC, or FLAC';
 
   @override
   String get trackConvertTitle => 'Convert Audio';
@@ -2741,14 +2786,14 @@ class AppLocalizationsKo extends AppLocalizations {
 
   @override
   String get downloadUseAlbumArtistForFoldersAlbumSubtitle =>
-      'Artist folders use Album Artist when available';
+      'Folder named after Album Artist tag';
 
   @override
   String get downloadUseAlbumArtistForFoldersTrackSubtitle =>
-      'Artist folders use Track Artist only';
+      'Folder named after Track Artist tag';
 
   @override
-  String get lyricsProvidersTitle => 'Lyrics Providers';
+  String get lyricsProvidersTitle => 'Lyrics Provider Priority';
 
   @override
   String get lyricsProvidersDescription =>
@@ -2756,7 +2801,7 @@ class AppLocalizationsKo extends AppLocalizations {
 
   @override
   String get lyricsProvidersInfoText =>
-      'Extension lyrics providers always run before built-in providers. At least one provider must remain enabled.';
+      'Extension lyrics providers run before built-in lyrics providers. At least one provider must remain enabled.';
 
   @override
   String lyricsProvidersEnabledSection(int count) {
@@ -2798,6 +2843,10 @@ class AppLocalizationsKo extends AppLocalizations {
   String get lyricsProviderQqMusicDesc =>
       'QQ Music (good for Chinese songs, via proxy)';
 
+  @override
+  String get lyricsProviderLyricsPlusDesc =>
+      'Word-by-word karaoke lyrics (Apple/Musixmatch/Spotify/QQ, via proxy)';
+
   @override
   String get lyricsProviderExtensionDesc => 'Extension provider';
 
@@ -2816,10 +2865,10 @@ class AppLocalizationsKo extends AppLocalizations {
   String get safMigrationSuccess => 'Download folder updated to SAF mode';
 
   @override
-  String get settingsDonate => 'Donate';
+  String get settingsDonate => 'Support Development';
 
   @override
-  String get settingsDonateSubtitle => 'Support SpotiFLAC-Mobile development';
+  String get settingsDonateSubtitle => 'Buy the developer a coffee';
 
   @override
   String get tooltipLoveAll => 'Love All';
@@ -2879,20 +2928,20 @@ class AppLocalizationsKo extends AppLocalizations {
 
   @override
   String get downloadLocationSubtitle =>
-      'Choose storage mode for downloaded files.';
+      'Choose where to save your downloaded tracks';
 
   @override
-  String get storageModeAppFolder => 'App folder (non-SAF)';
+  String get storageModeAppFolder => 'App Folder (Recommended)';
 
   @override
-  String get storageModeAppFolderSubtitle => 'Use default Music/SpotiFLAC path';
+  String get storageModeAppFolderSubtitle =>
+      'Saves to Music/SpotiFLAC by default';
 
   @override
-  String get storageModeSaf => 'SAF folder';
+  String get storageModeSaf => 'Custom Folder (SAF)';
 
   @override
-  String get storageModeSafSubtitle =>
-      'Pick folder via Android Storage Access Framework';
+  String get storageModeSafSubtitle => 'Pick any folder, including SD card';
 
   @override
   String downloadFilenameDescription(
@@ -2904,62 +2953,62 @@ class AppLocalizationsKo extends AppLocalizations {
     Object track,
     Object year,
   ) {
-    return 'Customize how your files are named.';
+    return 'Use $artist, $title, $album, $track, $year, $date, $disc as placeholders.';
   }
 
   @override
   String get downloadFilenameInsertTag => 'Tap to insert tag:';
 
   @override
-  String get downloadSeparateSinglesEnabled => 'Albums/ and Singles/ folders';
+  String get downloadSeparateSinglesEnabled =>
+      'Singles and EPs saved in a separate folder';
 
   @override
-  String get downloadSeparateSinglesDisabled => 'All files in same structure';
+  String get downloadSeparateSinglesDisabled =>
+      'Singles and albums saved in the same folder';
 
   @override
   String get downloadArtistNameFilters => 'Artist Name Filters';
 
   @override
-  String get downloadCreatePlaylistSourceFolder =>
-      'Create playlist source folder';
+  String get downloadCreatePlaylistSourceFolder => 'Playlist Source Folder';
 
   @override
   String get downloadCreatePlaylistSourceFolderEnabled =>
-      'Playlist downloads use Playlist/ plus your normal folder structure.';
+      'A subfolder is created for each playlist';
 
   @override
   String get downloadCreatePlaylistSourceFolderDisabled =>
-      'Playlist downloads use the normal folder structure only.';
+      'All tracks saved directly to download folder';
 
   @override
   String get downloadCreatePlaylistSourceFolderRedundant =>
-      'By Playlist already places downloads inside a playlist folder.';
+      'Handled by folder organization setting';
 
   @override
   String get downloadSongLinkRegion => 'SongLink Region';
 
   @override
-  String get downloadNetworkCompatibilityMode => 'Network compatibility mode';
+  String get downloadNetworkCompatibilityMode => 'Network Compatibility Mode';
 
   @override
   String get downloadNetworkCompatibilityModeEnabled =>
-      'Enabled: try HTTP + accept invalid TLS certificates (unsafe)';
+      'Using legacy TLS settings for older networks';
 
   @override
   String get downloadNetworkCompatibilityModeDisabled =>
-      'Off: strict HTTPS certificate validation (recommended)';
+      'Using standard network settings';
 
   @override
   String get downloadSelectServiceToEnable =>
-      'Select a built-in service to enable';
+      'Select a provider with quality options to enable this option';
 
   @override
   String get downloadSelectTidalQobuz =>
-      'Select Tidal or Qobuz above to configure quality';
+      'Select a provider with quality options to choose audio quality';
 
   @override
-  String get downloadEmbedLyricsDisabled =>
-      'Disabled while Embed Metadata is turned off';
+  String get downloadEmbedLyricsDisabled => 'Enable metadata embedding first';
 
   @override
   String get downloadNeteaseIncludeTranslation =>
@@ -2967,11 +3016,11 @@ class AppLocalizationsKo extends AppLocalizations {
 
   @override
   String get downloadNeteaseIncludeTranslationEnabled =>
-      'Append translated lyrics when available';
+      'Chinese translation lines included';
 
   @override
   String get downloadNeteaseIncludeTranslationDisabled =>
-      'Use original lyrics only';
+      'Original lyrics only';
 
   @override
   String get downloadNeteaseIncludeRomanization =>
@@ -2979,66 +3028,76 @@ class AppLocalizationsKo extends AppLocalizations {
 
   @override
   String get downloadNeteaseIncludeRomanizationEnabled =>
-      'Append romanized lyrics when available';
+      'Romanization lines included';
 
   @override
-  String get downloadNeteaseIncludeRomanizationDisabled => 'Disabled';
+  String get downloadNeteaseIncludeRomanizationDisabled => 'No romanization';
 
   @override
-  String get downloadAppleQqMultiPerson => 'Apple/QQ Multi-Person Word-by-Word';
+  String get downloadAppleQqMultiPerson => 'Apple / QQ: Multi-Person Lyrics';
 
   @override
   String get downloadAppleQqMultiPersonEnabled =>
-      'Enable v1/v2 speaker and [bg:] tags';
+      'Speaker labels included for duets and group tracks';
 
   @override
   String get downloadAppleQqMultiPersonDisabled =>
-      'Simplified word-by-word formatting';
+      'Standard lyrics without speaker labels';
+
+  @override
+  String get downloadAppleElrcWordSync => 'Apple Music eLRC Word Sync';
+
+  @override
+  String get downloadAppleElrcWordSyncEnabled =>
+      'Raw word-by-word timestamps preserved';
+
+  @override
+  String get downloadAppleElrcWordSyncDisabled =>
+      'Safer line-by-line Apple Music lyrics';
 
   @override
   String get downloadMusixmatchLanguage => 'Musixmatch Language';
 
   @override
-  String get downloadMusixmatchLanguageAuto => 'Auto (original)';
+  String get downloadMusixmatchLanguageAuto => 'Auto (original language)';
 
   @override
-  String get downloadFilterContributing =>
-      'Filter contributing artists in Album Artist';
+  String get downloadFilterContributing => 'Filter Contributing Artists';
 
   @override
   String get downloadFilterContributingEnabled =>
-      'Album Artist metadata uses primary artist only';
+      'Contributing artists removed from Album Artist folder name';
 
   @override
   String get downloadFilterContributingDisabled =>
-      'Keep full Album Artist metadata value';
+      'Full Album Artist string used';
 
   @override
-  String get downloadProvidersNoneEnabled => 'None enabled';
+  String get downloadProvidersNoneEnabled => 'No providers enabled';
 
   @override
   String get downloadMusixmatchLanguageCode => 'Language code';
 
   @override
-  String get downloadMusixmatchLanguageHint => 'auto / en / es / ja';
+  String get downloadMusixmatchLanguageHint => 'e.g. en, de, ja';
 
   @override
   String get downloadMusixmatchLanguageDesc =>
-      'Set preferred language code (example: en, es, ja). Leave empty for auto.';
+      'Enter a BCP-47 language code (e.g. en, de, ja) to request translated lyrics from Musixmatch.';
 
   @override
   String get downloadMusixmatchAuto => 'Auto';
 
   @override
-  String get downloadNetworkAnySubtitle => 'WiFi + Mobile Data';
+  String get downloadNetworkAnySubtitle => 'Use WiFi or mobile data';
 
   @override
   String get downloadNetworkWifiOnlySubtitle =>
-      'Pause downloads on mobile data';
+      'Downloads pause when on mobile data';
 
   @override
   String get downloadSongLinkRegionDesc =>
-      'Used as userCountry for SongLink API lookup.';
+      'Region used when resolving track links via SongLink. Choose the country where your streaming services are available.';
 
   @override
   String get snackbarUnsupportedAudioFormat => 'Unsupported audio format';
@@ -3241,6 +3300,15 @@ class AppLocalizationsKo extends AppLocalizations {
   @override
   String get audioAnalysisSampleRate => 'Sample Rate';
 
+  @override
+  String get audioAnalysisCodec => 'Codec';
+
+  @override
+  String get audioAnalysisContainer => 'Container';
+
+  @override
+  String get audioAnalysisDecodedFormat => 'Decoded Format';
+
   @override
   String get audioAnalysisBitDepth => 'Bit Depth';
 
@@ -3265,9 +3333,33 @@ class AppLocalizationsKo extends AppLocalizations {
   @override
   String get audioAnalysisRms => 'RMS';
 
+  @override
+  String get audioAnalysisLufs => 'LUFS';
+
+  @override
+  String get audioAnalysisTruePeak => 'True Peak';
+
+  @override
+  String get audioAnalysisClipping => 'Clipping';
+
+  @override
+  String get audioAnalysisNoClipping => 'No clipping';
+
+  @override
+  String get audioAnalysisSpectralCutoff => 'Spectral Cutoff';
+
+  @override
+  String get audioAnalysisChannelStats => 'Per-channel Stats';
+
   @override
   String get audioAnalysisSamples => 'Samples';
 
+  @override
+  String get audioAnalysisRescan => 'Re-analyze';
+
+  @override
+  String get audioAnalysisRescanning => 'Re-analyzing audio...';
+
   @override
   String extensionsSearchWith(String providerName) {
     return 'Search with $providerName';
@@ -3391,7 +3483,13 @@ class AppLocalizationsKo extends AppLocalizations {
 
   @override
   String notifTracksDownloadedSuccess(int count) {
-    return '$count tracks downloaded successfully';
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: '$count tracks downloaded successfully',
+      one: '1 track downloaded successfully',
+    );
+    return '$_temp0';
   }
 
   @override
@@ -3586,6 +3684,13 @@ class AppLocalizationsKo extends AppLocalizations {
   @override
   String get queueDownloadCompleted => 'Download completed';
 
+  @override
+  String get queueRateLimitTitle => 'Service rate limited';
+
+  @override
+  String get queueRateLimitMessage =>
+      'This track may still be available. Wait a few minutes, reduce parallel downloads, then retry.';
+
   @override
   String appearanceSelectAccentColor(String hex) {
     return 'Select accent color $hex';
@@ -3779,4 +3884,379 @@ class AppLocalizationsKo extends AppLocalizations {
   @override
   String get downloadFallbackExtensionsSubtitle =>
       'Choose which extensions can be used as fallback';
+
+  @override
+  String get editMetadataFieldDateHint => 'YYYY-MM-DD or YYYY';
+
+  @override
+  String get editMetadataFieldTrackTotal => 'Track Total';
+
+  @override
+  String get editMetadataFieldDiscTotal => 'Disc Total';
+
+  @override
+  String get editMetadataFieldComposer => 'Composer';
+
+  @override
+  String get editMetadataFieldComment => 'Comment';
+
+  @override
+  String get editMetadataAdvanced => 'Advanced';
+
+  @override
+  String get libraryFilterMetadataMissingTrackNumber => 'Missing track number';
+
+  @override
+  String get libraryFilterMetadataMissingDiscNumber => 'Missing disc number';
+
+  @override
+  String get libraryFilterMetadataMissingArtist => 'Missing artist';
+
+  @override
+  String get libraryFilterMetadataIncorrectIsrcFormat =>
+      'Incorrect ISRC format';
+
+  @override
+  String get libraryFilterMetadataMissingLabel => 'Missing label';
+
+  @override
+  String collectionDeletePlaylistsMessage(int count) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'playlists',
+      one: 'playlist',
+    );
+    return 'Delete $count $_temp0?';
+  }
+
+  @override
+  String collectionPlaylistsDeleted(int count) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'playlists',
+      one: 'playlist',
+    );
+    return '$count $_temp0 deleted';
+  }
+
+  @override
+  String collectionAddedTracksToPlaylist(int count, String playlistName) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'tracks',
+      one: 'track',
+    );
+    return 'Added $count $_temp0 to $playlistName';
+  }
+
+  @override
+  String collectionAddedTracksToPlaylistWithExisting(
+    int count,
+    String playlistName,
+    int alreadyCount,
+  ) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'tracks',
+      one: 'track',
+    );
+    return 'Added $count $_temp0 to $playlistName ($alreadyCount already in playlist)';
+  }
+
+  @override
+  String itemCount(int count) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'items',
+      one: 'item',
+    );
+    return '$count $_temp0';
+  }
+
+  @override
+  String trackReEnrichSuccessWithFailures(
+    int successCount,
+    int total,
+    int failedCount,
+  ) {
+    return 'Metadata re-enriched successfully ($successCount/$total) - Failed: $failedCount';
+  }
+
+  @override
+  String selectionDeleteTracksCount(int count) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'tracks',
+      one: 'track',
+    );
+    return 'Delete $count $_temp0';
+  }
+
+  @override
+  String queueDownloadSpeedStatus(String speed) {
+    return 'Downloading - $speed MB/s';
+  }
+
+  @override
+  String get queueDownloadStarting => 'Starting...';
+
+  @override
+  String get a11ySelectTrack => 'Select track';
+
+  @override
+  String get a11yDeselectTrack => 'Deselect track';
+
+  @override
+  String a11yPlayTrackByArtist(String trackName, String artistName) {
+    return 'Play $trackName by $artistName';
+  }
+
+  @override
+  String storeExtensionsCount(int count) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'extensions',
+      one: 'extension',
+    );
+    return '$count $_temp0';
+  }
+
+  @override
+  String storeRequiresVersion(String version) {
+    return 'Requires v$version+';
+  }
+
+  @override
+  String get actionGo => 'Go';
+
+  @override
+  String get logIssueSummary => 'Issue Summary';
+
+  @override
+  String logTotalErrors(int count) {
+    return 'Total errors: $count';
+  }
+
+  @override
+  String logAffectedDomains(String domains) {
+    return 'Affected: $domains';
+  }
+
+  @override
+  String get libraryScanCancelled => 'Scan cancelled';
+
+  @override
+  String get libraryScanCancelledSubtitle =>
+      'You can retry the scan when ready.';
+
+  @override
+  String libraryDownloadsHistoryExcluded(int count) {
+    return '$count from Downloads history (excluded from list)';
+  }
+
+  @override
+  String get downloadNativeWorker => 'Native download worker';
+
+  @override
+  String get downloadNativeWorkerSubtitle =>
+      'Beta Android service worker for extension downloads';
+
+  @override
+  String get badgeBeta => 'BETA';
+
+  @override
+  String get extensionServiceStatus => 'Service Status';
+
+  @override
+  String get extensionServiceHealth => 'Service health';
+
+  @override
+  String extensionHealthChecksConfigured(int count) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'checks',
+      one: 'check',
+    );
+    return '$count $_temp0 configured';
+  }
+
+  @override
+  String get extensionOauthConnectHint =>
+      'Tap Connect to Spotify to fill this field.';
+
+  @override
+  String extensionLastChecked(String time) {
+    return 'Last checked $time';
+  }
+
+  @override
+  String get extensionRefreshStatus => 'Refresh status';
+
+  @override
+  String get extensionCustomUrlHandling => 'Custom URL Handling';
+
+  @override
+  String get extensionCustomUrlHandlingSubtitle =>
+      'This extension can handle links from these sites';
+
+  @override
+  String get extensionCustomUrlHandlingShareHint =>
+      'Share links from these sites to SpotiFLAC Mobile and this extension will handle them.';
+
+  @override
+  String extensionSettingsCount(int count) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'settings',
+      one: 'setting',
+    );
+    return '$count $_temp0';
+  }
+
+  @override
+  String get extensionHealthOnline => 'Online';
+
+  @override
+  String get extensionHealthDegraded => 'Degraded';
+
+  @override
+  String get extensionHealthOffline => 'Offline';
+
+  @override
+  String get extensionHealthNotConfigured => 'Not configured';
+
+  @override
+  String get extensionHealthUnknown => 'Unknown';
+
+  @override
+  String get extensionHealthRequired => 'required';
+
+  @override
+  String get extensionSettingNotSet => 'Not set';
+
+  @override
+  String get extensionActionFailed => 'Action failed';
+
+  @override
+  String get extensionEnterValue => 'Enter value';
+
+  @override
+  String get extensionHealthServiceOnline => 'Service online';
+
+  @override
+  String get extensionHealthServiceDegraded => 'Service degraded';
+
+  @override
+  String get extensionHealthServiceOffline => 'Service offline';
+
+  @override
+  String get extensionHealthServiceUnknown => 'Service status unknown';
+
+  @override
+  String get audioAnalysisStereo => 'Stereo';
+
+  @override
+  String get audioAnalysisMono => 'Mono';
+
+  @override
+  String trackOpenInService(String serviceName) {
+    return 'Open in $serviceName';
+  }
+
+  @override
+  String get trackLyricsEmbeddedSource => 'Embedded';
+
+  @override
+  String get unknownAlbum => 'Unknown Album';
+
+  @override
+  String get unknownArtist => 'Unknown Artist';
+
+  @override
+  String get permissionAudio => 'Audio';
+
+  @override
+  String get permissionStorage => 'Storage';
+
+  @override
+  String get permissionNotification => 'Notification';
+
+  @override
+  String get errorInvalidFolderSelected => 'Invalid folder selected';
+
+  @override
+  String get errorCouldNotKeepFolderAccess =>
+      'Could not keep access to the selected folder';
+
+  @override
+  String get storeAnyVersion => 'Any';
+
+  @override
+  String get storeCategoryMetadata => 'Metadata';
+
+  @override
+  String get storeCategoryDownload => 'Download';
+
+  @override
+  String get storeCategoryUtility => 'Utility';
+
+  @override
+  String get storeCategoryLyrics => 'Lyrics';
+
+  @override
+  String get storeCategoryIntegration => 'Integration';
+
+  @override
+  String get artistReleases => 'Releases';
+
+  @override
+  String get editMetadataSelectNone => 'None';
+
+  @override
+  String queueRetryAllFailed(int count) {
+    return 'Retry $count failed';
+  }
+
+  @override
+  String get settingsSaveDownloadHistory => 'Save download history';
+
+  @override
+  String get settingsSaveDownloadHistorySubtitle =>
+      'Keep completed downloads in history and library views';
+
+  @override
+  String get dialogDisableHistoryTitle => 'Turn off download history?';
+
+  @override
+  String get dialogDisableHistoryMessage =>
+      'Existing history will be cleared. Downloaded files will not be deleted.';
+
+  @override
+  String get dialogDisableAndClear => 'Turn off and clear';
+
+  @override
+  String get openInOtherServices => 'Open in Other Services';
+
+  @override
+  String get shareSheetNoExtensions => 'No other compatible services';
+
+  @override
+  String get shareSheetNotFound => 'Not found';
+
+  @override
+  String get shareSheetCopyLink => 'Copy Link';
+
+  @override
+  String shareSheetLinkCopied(Object service) {
+    return '$service link copied';
+  }
 }

lib/l10n/app_localizations_nl.dart

@@ -126,7 +126,7 @@ class AppLocalizationsNl extends AppLocalizations {
 
   @override
   String get optionsPrimaryProviderSubtitle =>
-      'Service used when searching by track name.';
+      'Service used for searching by track or album name';
 
   @override
   String optionsUsingExtension(String extensionName) {
@@ -142,7 +142,7 @@ class AppLocalizationsNl extends AppLocalizations {
 
   @override
   String get optionsSwitchBack =>
-      'Tap Deezer or Spotify to switch back from extension';
+      'Choose the default search provider to switch back from an extension';
 
   @override
   String get optionsAutoFallback => 'Auto Fallback';
@@ -155,17 +155,19 @@ class AppLocalizationsNl extends AppLocalizations {
   String get optionsUseExtensionProviders => 'Use Extension Providers';
 
   @override
-  String get optionsUseExtensionProvidersOn => 'Extensions will be tried first';
+  String get optionsUseExtensionProvidersOn =>
+      'Extension providers are enabled';
 
   @override
-  String get optionsUseExtensionProvidersOff => 'Using built-in providers only';
+  String get optionsUseExtensionProvidersOff =>
+      'Extension providers are required';
 
   @override
   String get optionsEmbedLyrics => 'Embed Lyrics';
 
   @override
   String get optionsEmbedLyricsSubtitle =>
-      'Embed synced lyrics into FLAC files';
+      'Save synced lyrics alongside your downloaded tracks';
 
   @override
   String get optionsMaxQualityCover => 'Max Quality Cover';
@@ -185,6 +187,43 @@ class AppLocalizationsNl extends AppLocalizations {
   String get optionsReplayGainSubtitleOff =>
       'Disabled: no loudness normalization tags';
 
+  @override
+  String get trackReplayGain => 'Rescan ReplayGain';
+
+  @override
+  String get trackReplayGainSubtitle =>
+      'Analyze loudness and write ReplayGain tags';
+
+  @override
+  String get trackReplayGainScanning => 'Analyzing loudness...';
+
+  @override
+  String get trackReplayGainSuccess => 'ReplayGain tags added';
+
+  @override
+  String get trackReplayGainFailed => 'Failed to add ReplayGain tags';
+
+  @override
+  String selectionReplayGainCount(int count) {
+    return 'ReplayGain ($count)';
+  }
+
+  @override
+  String get replayGainBatchConfirmTitle => 'Add ReplayGain';
+
+  @override
+  String replayGainBatchConfirmMessage(int count) {
+    return 'Analyze loudness and write ReplayGain tags to $count track(s)?';
+  }
+
+  @override
+  String get replayGainBatchAnalyzing => 'Analyzing ReplayGain...';
+
+  @override
+  String replayGainBatchSuccess(int success, int total) {
+    return 'ReplayGain added to $success of $total tracks';
+  }
+
   @override
   String get optionsArtistTagMode => 'Artist Tag Mode';
 
@@ -206,21 +245,6 @@ class AppLocalizationsNl extends AppLocalizations {
   String get optionsArtistTagModeSplitVorbisSubtitle =>
       'Write one artist tag per artist for FLAC and Opus; MP3 and M4A stay joined.';
 
-  @override
-  String get optionsConcurrentDownloads => 'Concurrent Downloads';
-
-  @override
-  String get optionsConcurrentSequential => 'Sequentiële (1 per keer)';
-
-  @override
-  String optionsConcurrentParallel(int count) {
-    return '';
-  }
-
-  @override
-  String get optionsConcurrentWarning =>
-      'Parallel downloaden kan leiden tot rate-limiting';
-
   @override
   String get optionsExtensionStore => 'Extension Repo';
 
@@ -323,7 +347,7 @@ class AppLocalizationsNl extends AppLocalizations {
   String get aboutContributors => 'Contributors';
 
   @override
-  String get aboutMobileDeveloper => '';
+  String get aboutMobileDeveloper => 'Mobile version developer';
 
   @override
   String get aboutOriginalCreator => 'Creator of the original SpotiFLAC';
@@ -385,11 +409,11 @@ class AppLocalizationsNl extends AppLocalizations {
 
   @override
   String get aboutBinimumDesc =>
-      'The creator of QQDL & HiFi API. Without this API, Tidal downloads wouldn\'t exist!';
+      'The creator of QQDL & HiFi API. This project helped shape lossless download support.';
 
   @override
   String get aboutSachinsenalDesc =>
-      'The original HiFi project creator. The foundation of Tidal integration!';
+      'The original HiFi project creator. A foundation for lossless-source integration.';
 
   @override
   String get aboutSjdonadoDesc =>
@@ -397,7 +421,7 @@ class AppLocalizationsNl extends AppLocalizations {
 
   @override
   String get aboutAppDescription =>
-      'Download Spotify tracks in lossless quality from Tidal and Qobuz.';
+      'Search music metadata, manage extensions, and organize your library.';
 
   @override
   String get artistAlbums => 'Albums';
@@ -742,6 +766,9 @@ class AppLocalizationsNl extends AppLocalizations {
   @override
   String get errorNoTracksFound => 'No tracks found';
 
+  @override
+  String get searchEmptyResultSubtitle => 'Try another keyword';
+
   @override
   String get errorUrlNotRecognized => 'Link not recognized';
 
@@ -950,7 +977,7 @@ class AppLocalizationsNl extends AppLocalizations {
       'Only enabled extensions with download-provider capability are listed here.';
 
   @override
-  String get providerBuiltIn => 'Built-in';
+  String get providerBuiltIn => 'Legacy';
 
   @override
   String get providerExtension => 'Extension';
@@ -1118,10 +1145,10 @@ class AppLocalizationsNl extends AppLocalizations {
   String get settingsAppearanceSubtitle => 'Theme, colors, display';
 
   @override
-  String get settingsDownloadSubtitle => 'Service, quality, filename format';
+  String get settingsDownloadSubtitle => 'Service, quality, fallback';
 
   @override
-  String get settingsOptionsSubtitle => 'Fallback, lyrics, cover art, updates';
+  String get settingsOptionsSubtitle => 'Fallback, metadata, lyrics, cover art';
 
   @override
   String get settingsExtensionsSubtitle => 'Manage download providers';
@@ -1220,6 +1247,11 @@ class AppLocalizationsNl extends AppLocalizations {
   @override
   String get trackCopyLyrics => 'Copy lyrics';
 
+  @override
+  String trackLyricsSource(String source) {
+    return 'Source: $source';
+  }
+
   @override
   String get trackLyricsNotAvailable => 'Lyrics not available for this track';
 
@@ -1338,10 +1370,11 @@ class AppLocalizationsNl extends AppLocalizations {
   String get storeEmptyNoResults => 'No extensions found';
 
   @override
-  String get extensionDefaultProvider => 'Default (Deezer)';
+  String get extensionDefaultProvider => 'Default Search';
 
   @override
-  String get extensionDefaultProviderSubtitle => 'Use built-in search';
+  String get extensionDefaultProviderSubtitle =>
+      'Use the default metadata search';
 
   @override
   String get extensionAuthor => 'Author';
@@ -1515,7 +1548,7 @@ class AppLocalizationsNl extends AppLocalizations {
 
   @override
   String get downloadLossy320FormatDesc =>
-      'Choose the output format for Tidal 320kbps lossy downloads. The original AAC stream will be converted to your selected format.';
+      'Choose the output format for 320kbps lossy downloads. The original stream will be converted to your selected format when needed.';
 
   @override
   String get downloadLossyMp3 => 'MP3 320kbps';
@@ -1523,6 +1556,13 @@ class AppLocalizationsNl extends AppLocalizations {
   @override
   String get downloadLossyMp3Subtitle => 'Best compatibility, ~10MB per track';
 
+  @override
+  String get downloadLossyAac => 'AAC/M4A 320kbps';
+
+  @override
+  String get downloadLossyAacSubtitle =>
+      'Best mobile compatibility, M4A container';
+
   @override
   String get downloadLossyOpus256 => 'Opus 256kbps';
 
@@ -2078,7 +2118,7 @@ class AppLocalizationsNl extends AppLocalizations {
 
   @override
   String get tutorialWelcomeTip2 =>
-      'Get FLAC quality audio from Tidal, Qobuz, or Deezer';
+      'Get FLAC quality audio from installed download extensions';
 
   @override
   String get tutorialWelcomeTip3 =>
@@ -2408,7 +2448,7 @@ class AppLocalizationsNl extends AppLocalizations {
 
   @override
   String get trackConvertFormatSubtitle =>
-      'Convert to MP3, Opus, ALAC, or FLAC';
+      'Convert to AAC/M4A, MP3, Opus, ALAC, or FLAC';
 
   @override
   String get trackConvertTitle => 'Convert Audio';
@@ -2761,14 +2801,14 @@ class AppLocalizationsNl extends AppLocalizations {
 
   @override
   String get downloadUseAlbumArtistForFoldersAlbumSubtitle =>
-      'Artist folders use Album Artist when available';
+      'Folder named after Album Artist tag';
 
   @override
   String get downloadUseAlbumArtistForFoldersTrackSubtitle =>
-      'Artist folders use Track Artist only';
+      'Folder named after Track Artist tag';
 
   @override
-  String get lyricsProvidersTitle => 'Lyrics Providers';
+  String get lyricsProvidersTitle => 'Lyrics Provider Priority';
 
   @override
   String get lyricsProvidersDescription =>
@@ -2776,7 +2816,7 @@ class AppLocalizationsNl extends AppLocalizations {
 
   @override
   String get lyricsProvidersInfoText =>
-      'Extension lyrics providers always run before built-in providers. At least one provider must remain enabled.';
+      'Extension lyrics providers run before built-in lyrics providers. At least one provider must remain enabled.';
 
   @override
   String lyricsProvidersEnabledSection(int count) {
@@ -2818,6 +2858,10 @@ class AppLocalizationsNl extends AppLocalizations {
   String get lyricsProviderQqMusicDesc =>
       'QQ Music (good for Chinese songs, via proxy)';
 
+  @override
+  String get lyricsProviderLyricsPlusDesc =>
+      'Word-by-word karaoke lyrics (Apple/Musixmatch/Spotify/QQ, via proxy)';
+
   @override
   String get lyricsProviderExtensionDesc => 'Extension provider';
 
@@ -2836,10 +2880,10 @@ class AppLocalizationsNl extends AppLocalizations {
   String get safMigrationSuccess => 'Download folder updated to SAF mode';
 
   @override
-  String get settingsDonate => 'Donate';
+  String get settingsDonate => 'Support Development';
 
   @override
-  String get settingsDonateSubtitle => 'Support SpotiFLAC-Mobile development';
+  String get settingsDonateSubtitle => 'Buy the developer a coffee';
 
   @override
   String get tooltipLoveAll => 'Love All';
@@ -2899,20 +2943,20 @@ class AppLocalizationsNl extends AppLocalizations {
 
   @override
   String get downloadLocationSubtitle =>
-      'Choose storage mode for downloaded files.';
+      'Choose where to save your downloaded tracks';
 
   @override
-  String get storageModeAppFolder => 'App folder (non-SAF)';
+  String get storageModeAppFolder => 'App Folder (Recommended)';
 
   @override
-  String get storageModeAppFolderSubtitle => 'Use default Music/SpotiFLAC path';
+  String get storageModeAppFolderSubtitle =>
+      'Saves to Music/SpotiFLAC by default';
 
   @override
-  String get storageModeSaf => 'SAF folder';
+  String get storageModeSaf => 'Custom Folder (SAF)';
 
   @override
-  String get storageModeSafSubtitle =>
-      'Pick folder via Android Storage Access Framework';
+  String get storageModeSafSubtitle => 'Pick any folder, including SD card';
 
   @override
   String downloadFilenameDescription(
@@ -2924,62 +2968,62 @@ class AppLocalizationsNl extends AppLocalizations {
     Object track,
     Object year,
   ) {
-    return 'Customize how your files are named.';
+    return 'Use $artist, $title, $album, $track, $year, $date, $disc as placeholders.';
   }
 
   @override
   String get downloadFilenameInsertTag => 'Tap to insert tag:';
 
   @override
-  String get downloadSeparateSinglesEnabled => 'Albums/ and Singles/ folders';
+  String get downloadSeparateSinglesEnabled =>
+      'Singles and EPs saved in a separate folder';
 
   @override
-  String get downloadSeparateSinglesDisabled => 'All files in same structure';
+  String get downloadSeparateSinglesDisabled =>
+      'Singles and albums saved in the same folder';
 
   @override
   String get downloadArtistNameFilters => 'Artist Name Filters';
 
   @override
-  String get downloadCreatePlaylistSourceFolder =>
-      'Create playlist source folder';
+  String get downloadCreatePlaylistSourceFolder => 'Playlist Source Folder';
 
   @override
   String get downloadCreatePlaylistSourceFolderEnabled =>
-      'Playlist downloads use Playlist/ plus your normal folder structure.';
+      'A subfolder is created for each playlist';
 
   @override
   String get downloadCreatePlaylistSourceFolderDisabled =>
-      'Playlist downloads use the normal folder structure only.';
+      'All tracks saved directly to download folder';
 
   @override
   String get downloadCreatePlaylistSourceFolderRedundant =>
-      'By Playlist already places downloads inside a playlist folder.';
+      'Handled by folder organization setting';
 
   @override
   String get downloadSongLinkRegion => 'SongLink Region';
 
   @override
-  String get downloadNetworkCompatibilityMode => 'Network compatibility mode';
+  String get downloadNetworkCompatibilityMode => 'Network Compatibility Mode';
 
   @override
   String get downloadNetworkCompatibilityModeEnabled =>
-      'Enabled: try HTTP + accept invalid TLS certificates (unsafe)';
+      'Using legacy TLS settings for older networks';
 
   @override
   String get downloadNetworkCompatibilityModeDisabled =>
-      'Off: strict HTTPS certificate validation (recommended)';
+      'Using standard network settings';
 
   @override
   String get downloadSelectServiceToEnable =>
-      'Select a built-in service to enable';
+      'Select a provider with quality options to enable this option';
 
   @override
   String get downloadSelectTidalQobuz =>
-      'Select Tidal or Qobuz above to configure quality';
+      'Select a provider with quality options to choose audio quality';
 
   @override
-  String get downloadEmbedLyricsDisabled =>
-      'Disabled while Embed Metadata is turned off';
+  String get downloadEmbedLyricsDisabled => 'Enable metadata embedding first';
 
   @override
   String get downloadNeteaseIncludeTranslation =>
@@ -2987,11 +3031,11 @@ class AppLocalizationsNl extends AppLocalizations {
 
   @override
   String get downloadNeteaseIncludeTranslationEnabled =>
-      'Append translated lyrics when available';
+      'Chinese translation lines included';
 
   @override
   String get downloadNeteaseIncludeTranslationDisabled =>
-      'Use original lyrics only';
+      'Original lyrics only';
 
   @override
   String get downloadNeteaseIncludeRomanization =>
@@ -2999,66 +3043,76 @@ class AppLocalizationsNl extends AppLocalizations {
 
   @override
   String get downloadNeteaseIncludeRomanizationEnabled =>
-      'Append romanized lyrics when available';
+      'Romanization lines included';
 
   @override
-  String get downloadNeteaseIncludeRomanizationDisabled => 'Disabled';
+  String get downloadNeteaseIncludeRomanizationDisabled => 'No romanization';
 
   @override
-  String get downloadAppleQqMultiPerson => 'Apple/QQ Multi-Person Word-by-Word';
+  String get downloadAppleQqMultiPerson => 'Apple / QQ: Multi-Person Lyrics';
 
   @override
   String get downloadAppleQqMultiPersonEnabled =>
-      'Enable v1/v2 speaker and [bg:] tags';
+      'Speaker labels included for duets and group tracks';
 
   @override
   String get downloadAppleQqMultiPersonDisabled =>
-      'Simplified word-by-word formatting';
+      'Standard lyrics without speaker labels';
+
+  @override
+  String get downloadAppleElrcWordSync => 'Apple Music eLRC Word Sync';
+
+  @override
+  String get downloadAppleElrcWordSyncEnabled =>
+      'Raw word-by-word timestamps preserved';
+
+  @override
+  String get downloadAppleElrcWordSyncDisabled =>
+      'Safer line-by-line Apple Music lyrics';
 
   @override
   String get downloadMusixmatchLanguage => 'Musixmatch Language';
 
   @override
-  String get downloadMusixmatchLanguageAuto => 'Auto (original)';
+  String get downloadMusixmatchLanguageAuto => 'Auto (original language)';
 
   @override
-  String get downloadFilterContributing =>
-      'Filter contributing artists in Album Artist';
+  String get downloadFilterContributing => 'Filter Contributing Artists';
 
   @override
   String get downloadFilterContributingEnabled =>
-      'Album Artist metadata uses primary artist only';
+      'Contributing artists removed from Album Artist folder name';
 
   @override
   String get downloadFilterContributingDisabled =>
-      'Keep full Album Artist metadata value';
+      'Full Album Artist string used';
 
   @override
-  String get downloadProvidersNoneEnabled => 'None enabled';
+  String get downloadProvidersNoneEnabled => 'No providers enabled';
 
   @override
   String get downloadMusixmatchLanguageCode => 'Language code';
 
   @override
-  String get downloadMusixmatchLanguageHint => 'auto / en / es / ja';
+  String get downloadMusixmatchLanguageHint => 'e.g. en, de, ja';
 
   @override
   String get downloadMusixmatchLanguageDesc =>
-      'Set preferred language code (example: en, es, ja). Leave empty for auto.';
+      'Enter a BCP-47 language code (e.g. en, de, ja) to request translated lyrics from Musixmatch.';
 
   @override
   String get downloadMusixmatchAuto => 'Auto';
 
   @override
-  String get downloadNetworkAnySubtitle => 'WiFi + Mobile Data';
+  String get downloadNetworkAnySubtitle => 'Use WiFi or mobile data';
 
   @override
   String get downloadNetworkWifiOnlySubtitle =>
-      'Pause downloads on mobile data';
+      'Downloads pause when on mobile data';
 
   @override
   String get downloadSongLinkRegionDesc =>
-      'Used as userCountry for SongLink API lookup.';
+      'Region used when resolving track links via SongLink. Choose the country where your streaming services are available.';
 
   @override
   String get snackbarUnsupportedAudioFormat => 'Unsupported audio format';
@@ -3261,6 +3315,15 @@ class AppLocalizationsNl extends AppLocalizations {
   @override
   String get audioAnalysisSampleRate => 'Sample Rate';
 
+  @override
+  String get audioAnalysisCodec => 'Codec';
+
+  @override
+  String get audioAnalysisContainer => 'Container';
+
+  @override
+  String get audioAnalysisDecodedFormat => 'Decoded Format';
+
   @override
   String get audioAnalysisBitDepth => 'Bit Depth';
 
@@ -3285,9 +3348,33 @@ class AppLocalizationsNl extends AppLocalizations {
   @override
   String get audioAnalysisRms => 'RMS';
 
+  @override
+  String get audioAnalysisLufs => 'LUFS';
+
+  @override
+  String get audioAnalysisTruePeak => 'True Peak';
+
+  @override
+  String get audioAnalysisClipping => 'Clipping';
+
+  @override
+  String get audioAnalysisNoClipping => 'No clipping';
+
+  @override
+  String get audioAnalysisSpectralCutoff => 'Spectral Cutoff';
+
+  @override
+  String get audioAnalysisChannelStats => 'Per-channel Stats';
+
   @override
   String get audioAnalysisSamples => 'Samples';
 
+  @override
+  String get audioAnalysisRescan => 'Re-analyze';
+
+  @override
+  String get audioAnalysisRescanning => 'Re-analyzing audio...';
+
   @override
   String extensionsSearchWith(String providerName) {
     return 'Search with $providerName';
@@ -3411,7 +3498,13 @@ class AppLocalizationsNl extends AppLocalizations {
 
   @override
   String notifTracksDownloadedSuccess(int count) {
-    return '$count tracks downloaded successfully';
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: '$count tracks downloaded successfully',
+      one: '1 track downloaded successfully',
+    );
+    return '$_temp0';
   }
 
   @override
@@ -3606,6 +3699,13 @@ class AppLocalizationsNl extends AppLocalizations {
   @override
   String get queueDownloadCompleted => 'Download completed';
 
+  @override
+  String get queueRateLimitTitle => 'Service rate limited';
+
+  @override
+  String get queueRateLimitMessage =>
+      'This track may still be available. Wait a few minutes, reduce parallel downloads, then retry.';
+
   @override
   String appearanceSelectAccentColor(String hex) {
     return 'Select accent color $hex';
@@ -3799,4 +3899,379 @@ class AppLocalizationsNl extends AppLocalizations {
   @override
   String get downloadFallbackExtensionsSubtitle =>
       'Choose which extensions can be used as fallback';
+
+  @override
+  String get editMetadataFieldDateHint => 'YYYY-MM-DD or YYYY';
+
+  @override
+  String get editMetadataFieldTrackTotal => 'Track Total';
+
+  @override
+  String get editMetadataFieldDiscTotal => 'Disc Total';
+
+  @override
+  String get editMetadataFieldComposer => 'Composer';
+
+  @override
+  String get editMetadataFieldComment => 'Comment';
+
+  @override
+  String get editMetadataAdvanced => 'Advanced';
+
+  @override
+  String get libraryFilterMetadataMissingTrackNumber => 'Missing track number';
+
+  @override
+  String get libraryFilterMetadataMissingDiscNumber => 'Missing disc number';
+
+  @override
+  String get libraryFilterMetadataMissingArtist => 'Missing artist';
+
+  @override
+  String get libraryFilterMetadataIncorrectIsrcFormat =>
+      'Incorrect ISRC format';
+
+  @override
+  String get libraryFilterMetadataMissingLabel => 'Missing label';
+
+  @override
+  String collectionDeletePlaylistsMessage(int count) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'playlists',
+      one: 'playlist',
+    );
+    return 'Delete $count $_temp0?';
+  }
+
+  @override
+  String collectionPlaylistsDeleted(int count) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'playlists',
+      one: 'playlist',
+    );
+    return '$count $_temp0 deleted';
+  }
+
+  @override
+  String collectionAddedTracksToPlaylist(int count, String playlistName) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'tracks',
+      one: 'track',
+    );
+    return 'Added $count $_temp0 to $playlistName';
+  }
+
+  @override
+  String collectionAddedTracksToPlaylistWithExisting(
+    int count,
+    String playlistName,
+    int alreadyCount,
+  ) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'tracks',
+      one: 'track',
+    );
+    return 'Added $count $_temp0 to $playlistName ($alreadyCount already in playlist)';
+  }
+
+  @override
+  String itemCount(int count) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'items',
+      one: 'item',
+    );
+    return '$count $_temp0';
+  }
+
+  @override
+  String trackReEnrichSuccessWithFailures(
+    int successCount,
+    int total,
+    int failedCount,
+  ) {
+    return 'Metadata re-enriched successfully ($successCount/$total) - Failed: $failedCount';
+  }
+
+  @override
+  String selectionDeleteTracksCount(int count) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'tracks',
+      one: 'track',
+    );
+    return 'Delete $count $_temp0';
+  }
+
+  @override
+  String queueDownloadSpeedStatus(String speed) {
+    return 'Downloading - $speed MB/s';
+  }
+
+  @override
+  String get queueDownloadStarting => 'Starting...';
+
+  @override
+  String get a11ySelectTrack => 'Select track';
+
+  @override
+  String get a11yDeselectTrack => 'Deselect track';
+
+  @override
+  String a11yPlayTrackByArtist(String trackName, String artistName) {
+    return 'Play $trackName by $artistName';
+  }
+
+  @override
+  String storeExtensionsCount(int count) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'extensions',
+      one: 'extension',
+    );
+    return '$count $_temp0';
+  }
+
+  @override
+  String storeRequiresVersion(String version) {
+    return 'Requires v$version+';
+  }
+
+  @override
+  String get actionGo => 'Go';
+
+  @override
+  String get logIssueSummary => 'Issue Summary';
+
+  @override
+  String logTotalErrors(int count) {
+    return 'Total errors: $count';
+  }
+
+  @override
+  String logAffectedDomains(String domains) {
+    return 'Affected: $domains';
+  }
+
+  @override
+  String get libraryScanCancelled => 'Scan cancelled';
+
+  @override
+  String get libraryScanCancelledSubtitle =>
+      'You can retry the scan when ready.';
+
+  @override
+  String libraryDownloadsHistoryExcluded(int count) {
+    return '$count from Downloads history (excluded from list)';
+  }
+
+  @override
+  String get downloadNativeWorker => 'Native download worker';
+
+  @override
+  String get downloadNativeWorkerSubtitle =>
+      'Beta Android service worker for extension downloads';
+
+  @override
+  String get badgeBeta => 'BETA';
+
+  @override
+  String get extensionServiceStatus => 'Service Status';
+
+  @override
+  String get extensionServiceHealth => 'Service health';
+
+  @override
+  String extensionHealthChecksConfigured(int count) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'checks',
+      one: 'check',
+    );
+    return '$count $_temp0 configured';
+  }
+
+  @override
+  String get extensionOauthConnectHint =>
+      'Tap Connect to Spotify to fill this field.';
+
+  @override
+  String extensionLastChecked(String time) {
+    return 'Last checked $time';
+  }
+
+  @override
+  String get extensionRefreshStatus => 'Refresh status';
+
+  @override
+  String get extensionCustomUrlHandling => 'Custom URL Handling';
+
+  @override
+  String get extensionCustomUrlHandlingSubtitle =>
+      'This extension can handle links from these sites';
+
+  @override
+  String get extensionCustomUrlHandlingShareHint =>
+      'Share links from these sites to SpotiFLAC Mobile and this extension will handle them.';
+
+  @override
+  String extensionSettingsCount(int count) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'settings',
+      one: 'setting',
+    );
+    return '$count $_temp0';
+  }
+
+  @override
+  String get extensionHealthOnline => 'Online';
+
+  @override
+  String get extensionHealthDegraded => 'Degraded';
+
+  @override
+  String get extensionHealthOffline => 'Offline';
+
+  @override
+  String get extensionHealthNotConfigured => 'Not configured';
+
+  @override
+  String get extensionHealthUnknown => 'Unknown';
+
+  @override
+  String get extensionHealthRequired => 'required';
+
+  @override
+  String get extensionSettingNotSet => 'Not set';
+
+  @override
+  String get extensionActionFailed => 'Action failed';
+
+  @override
+  String get extensionEnterValue => 'Enter value';
+
+  @override
+  String get extensionHealthServiceOnline => 'Service online';
+
+  @override
+  String get extensionHealthServiceDegraded => 'Service degraded';
+
+  @override
+  String get extensionHealthServiceOffline => 'Service offline';
+
+  @override
+  String get extensionHealthServiceUnknown => 'Service status unknown';
+
+  @override
+  String get audioAnalysisStereo => 'Stereo';
+
+  @override
+  String get audioAnalysisMono => 'Mono';
+
+  @override
+  String trackOpenInService(String serviceName) {
+    return 'Open in $serviceName';
+  }
+
+  @override
+  String get trackLyricsEmbeddedSource => 'Embedded';
+
+  @override
+  String get unknownAlbum => 'Unknown Album';
+
+  @override
+  String get unknownArtist => 'Unknown Artist';
+
+  @override
+  String get permissionAudio => 'Audio';
+
+  @override
+  String get permissionStorage => 'Storage';
+
+  @override
+  String get permissionNotification => 'Notification';
+
+  @override
+  String get errorInvalidFolderSelected => 'Invalid folder selected';
+
+  @override
+  String get errorCouldNotKeepFolderAccess =>
+      'Could not keep access to the selected folder';
+
+  @override
+  String get storeAnyVersion => 'Any';
+
+  @override
+  String get storeCategoryMetadata => 'Metadata';
+
+  @override
+  String get storeCategoryDownload => 'Download';
+
+  @override
+  String get storeCategoryUtility => 'Utility';
+
+  @override
+  String get storeCategoryLyrics => 'Lyrics';
+
+  @override
+  String get storeCategoryIntegration => 'Integration';
+
+  @override
+  String get artistReleases => 'Releases';
+
+  @override
+  String get editMetadataSelectNone => 'None';
+
+  @override
+  String queueRetryAllFailed(int count) {
+    return 'Retry $count failed';
+  }
+
+  @override
+  String get settingsSaveDownloadHistory => 'Save download history';
+
+  @override
+  String get settingsSaveDownloadHistorySubtitle =>
+      'Keep completed downloads in history and library views';
+
+  @override
+  String get dialogDisableHistoryTitle => 'Turn off download history?';
+
+  @override
+  String get dialogDisableHistoryMessage =>
+      'Existing history will be cleared. Downloaded files will not be deleted.';
+
+  @override
+  String get dialogDisableAndClear => 'Turn off and clear';
+
+  @override
+  String get openInOtherServices => 'Open in Other Services';
+
+  @override
+  String get shareSheetNoExtensions => 'No other compatible services';
+
+  @override
+  String get shareSheetNotFound => 'Not found';
+
+  @override
+  String get shareSheetCopyLink => 'Copy Link';
+
+  @override
+  String shareSheetLinkCopied(Object service) {
+    return '$service link copied';
+  }
 }

lib/l10n/app_localizations_uk.dart

@@ -129,7 +129,7 @@ class AppLocalizationsUk extends AppLocalizations {
 
   @override
   String get optionsPrimaryProviderSubtitle =>
-      'Розширення будуть випробувані першими';
+      'Service used for searching by track or album name';
 
   @override
   String optionsUsingExtension(String extensionName) {
@@ -137,15 +137,15 @@ class AppLocalizationsUk extends AppLocalizations {
   }
 
   @override
-  String get optionsDefaultSearchTab => 'Default Search Tab';
+  String get optionsDefaultSearchTab => 'Вкладка пошуку за замовчуванням';
 
   @override
   String get optionsDefaultSearchTabSubtitle =>
-      'Choose which tab opens first for new search results.';
+      'Виберіть, яка вкладка відкриється першою для нових результатів пошуку.';
 
   @override
   String get optionsSwitchBack =>
-      'Натисніть Deezer або Spotify, щоб повернутися до розширення';
+      'Choose the default search provider to switch back from an extension';
 
   @override
   String get optionsAutoFallback => 'Автоматичний резервний варіант';
@@ -160,18 +160,18 @@ class AppLocalizationsUk extends AppLocalizations {
 
   @override
   String get optionsUseExtensionProvidersOn =>
-      'Розширення будуть випробувані першими';
+      'Extension providers are enabled';
 
   @override
   String get optionsUseExtensionProvidersOff =>
-      'Використати лише вбудованих постачальників';
+      'Extension providers are required';
 
   @override
   String get optionsEmbedLyrics => 'Вбудований текст пісні';
 
   @override
   String get optionsEmbedLyricsSubtitle =>
-      'Вбудовувати синхронізовані тексти пісень у файли FLAC';
+      'Save synced lyrics alongside your downloaded tracks';
 
   @override
   String get optionsMaxQualityCover => 'Максимальна якість обкладинки';
@@ -191,6 +191,43 @@ class AppLocalizationsUk extends AppLocalizations {
   String get optionsReplayGainSubtitleOff =>
       'Вимкнено: немає тегів нормалізації гучності';
 
+  @override
+  String get trackReplayGain => 'Rescan ReplayGain';
+
+  @override
+  String get trackReplayGainSubtitle =>
+      'Analyze loudness and write ReplayGain tags';
+
+  @override
+  String get trackReplayGainScanning => 'Analyzing loudness...';
+
+  @override
+  String get trackReplayGainSuccess => 'ReplayGain tags added';
+
+  @override
+  String get trackReplayGainFailed => 'Failed to add ReplayGain tags';
+
+  @override
+  String selectionReplayGainCount(int count) {
+    return 'ReplayGain ($count)';
+  }
+
+  @override
+  String get replayGainBatchConfirmTitle => 'Add ReplayGain';
+
+  @override
+  String replayGainBatchConfirmMessage(int count) {
+    return 'Analyze loudness and write ReplayGain tags to $count track(s)?';
+  }
+
+  @override
+  String get replayGainBatchAnalyzing => 'Analyzing ReplayGain...';
+
+  @override
+  String replayGainBatchSuccess(int success, int total) {
+    return 'ReplayGain added to $success of $total tracks';
+  }
+
   @override
   String get optionsArtistTagMode => 'Режим тегу виконавця';
 
@@ -212,21 +249,6 @@ class AppLocalizationsUk extends AppLocalizations {
   String get optionsArtistTagModeSplitVorbisSubtitle =>
       'Для FLAC та Opus на кожного виконавця додати окремий тег виконавця; MP3 та M4A залишаються об’єднаними.';
 
-  @override
-  String get optionsConcurrentDownloads => 'Кількість одночасних завантажень';
-
-  @override
-  String get optionsConcurrentSequential => 'Послідовно (по одному за раз)';
-
-  @override
-  String optionsConcurrentParallel(int count) {
-    return '$count паралельних завантажень';
-  }
-
-  @override
-  String get optionsConcurrentWarning =>
-      'Паралельні завантаження можуть призвести до обмеження швидкості';
-
   @override
   String get optionsExtensionStore => 'Репозиторій розширень';
 
@@ -395,11 +417,11 @@ class AppLocalizationsUk extends AppLocalizations {
 
   @override
   String get aboutBinimumDesc =>
-      'Творець QQDL та HiFi API. Без цього API завантажень Tidal\'а не існувало б!';
+      'The creator of QQDL & HiFi API. This project helped shape lossless download support.';
 
   @override
   String get aboutSachinsenalDesc =>
-      'Оригінальний творець HiFi-проектів. Основа інтеграції Tidal!';
+      'The original HiFi project creator. A foundation for lossless-source integration.';
 
   @override
   String get aboutSjdonadoDesc =>
@@ -407,7 +429,7 @@ class AppLocalizationsUk extends AppLocalizations {
 
   @override
   String get aboutAppDescription =>
-      'Кінцеві точки потокового передавання Tidal Hi-Res FLAC. Ключовий елемент пазлу музики без втрат.';
+      'Search music metadata, manage extensions, and organize your library.';
 
   @override
   String get artistAlbums => 'Альбоми';
@@ -755,6 +777,9 @@ class AppLocalizationsUk extends AppLocalizations {
   @override
   String get errorNoTracksFound => 'Треків не знайдено';
 
+  @override
+  String get searchEmptyResultSubtitle => 'Try another keyword';
+
   @override
   String get errorUrlNotRecognized => 'Посилання не розпізнано';
 
@@ -956,14 +981,14 @@ class AppLocalizationsUk extends AppLocalizations {
 
   @override
   String get providerPriorityFallbackExtensionsDescription =>
-      'Виберіть, які встановлені розширення завантаження можна використовувати під час автоматичного відновлення до попереднього режиму. Вбудовані постачальники все одно дотримуються порядку пріоритетності, зазначеного вище.';
+      'Choose which installed download extensions can be used during automatic fallback.';
 
   @override
   String get providerPriorityFallbackExtensionsHint =>
       'Тут перелічені лише ввімкнені розширення з можливістю завантаження через постачальника послуг.';
 
   @override
-  String get providerBuiltIn => 'Вбудований';
+  String get providerBuiltIn => 'Legacy';
 
   @override
   String get providerExtension => 'Розширення';
@@ -1134,11 +1159,10 @@ class AppLocalizationsUk extends AppLocalizations {
   String get settingsAppearanceSubtitle => 'Тема, кольори, дисплей';
 
   @override
-  String get settingsDownloadSubtitle => 'Сервіс, якість, формат назви файлу';
+  String get settingsDownloadSubtitle => 'Service, quality, fallback';
 
   @override
-  String get settingsOptionsSubtitle =>
-      'Резервний варіант, тексти пісень, обкладинка, оновлення';
+  String get settingsOptionsSubtitle => 'Fallback, metadata, lyrics, cover art';
 
   @override
   String get settingsExtensionsSubtitle =>
@@ -1240,6 +1264,11 @@ class AppLocalizationsUk extends AppLocalizations {
   @override
   String get trackCopyLyrics => 'Скопіювати тексти пісень';
 
+  @override
+  String trackLyricsSource(String source) {
+    return 'Source: $source';
+  }
+
   @override
   String get trackLyricsNotAvailable =>
       'Текст пісні для цього треку недоступний';
@@ -1360,10 +1389,11 @@ class AppLocalizationsUk extends AppLocalizations {
   String get storeEmptyNoResults => 'Розширень не знайдено';
 
   @override
-  String get extensionDefaultProvider => 'За замовчуванням (Deezer)';
+  String get extensionDefaultProvider => 'Default Search';
 
   @override
-  String get extensionDefaultProviderSubtitle => 'Використати вбудований пошук';
+  String get extensionDefaultProviderSubtitle =>
+      'Use the default metadata search';
 
   @override
   String get extensionAuthor => 'Автор';
@@ -1539,7 +1569,7 @@ class AppLocalizationsUk extends AppLocalizations {
 
   @override
   String get downloadLossy320FormatDesc =>
-      'Виберіть вихідний формат для завантажень Tidal 320 кбіт/с із втратами. Оригінальний потік AAC буде конвертовано у вибраний вами формат.';
+      'Choose the output format for 320kbps lossy downloads. The original stream will be converted to your selected format when needed.';
 
   @override
   String get downloadLossyMp3 => 'MP3 320 кбіт/с';
@@ -1548,6 +1578,13 @@ class AppLocalizationsUk extends AppLocalizations {
   String get downloadLossyMp3Subtitle =>
       'Найкраща сумісність, ~10 МБ на доріжку';
 
+  @override
+  String get downloadLossyAac => 'AAC/M4A 320kbps';
+
+  @override
+  String get downloadLossyAacSubtitle =>
+      'Best mobile compatibility, M4A container';
+
   @override
   String get downloadLossyOpus256 => 'Opus 256 кбіт/с';
 
@@ -2114,7 +2151,7 @@ class AppLocalizationsUk extends AppLocalizations {
 
   @override
   String get tutorialWelcomeTip2 =>
-      'Отримуйте аудіо у якості FLAC з Tidal, Qobuz або Deezer';
+      'Get FLAC quality audio from installed download extensions';
 
   @override
   String get tutorialWelcomeTip3 =>
@@ -2449,7 +2486,7 @@ class AppLocalizationsUk extends AppLocalizations {
 
   @override
   String get trackConvertFormatSubtitle =>
-      'Конвертувати в MP3, Opus, ALAC або FLAC';
+      'Convert to AAC/M4A, MP3, Opus, ALAC, or FLAC';
 
   @override
   String get trackConvertTitle => 'Конвертувати аудіо';
@@ -2806,14 +2843,14 @@ class AppLocalizationsUk extends AppLocalizations {
 
   @override
   String get downloadUseAlbumArtistForFoldersAlbumSubtitle =>
-      'Папки виконавців використовують \"Виконавець альбому\", коли це можливо';
+      'Folder named after Album Artist tag';
 
   @override
   String get downloadUseAlbumArtistForFoldersTrackSubtitle =>
-      'Папки виконавців використовують лише виконавця доріжки';
+      'Folder named after Track Artist tag';
 
   @override
-  String get lyricsProvidersTitle => 'Постачальники текстів пісень';
+  String get lyricsProvidersTitle => 'Lyrics Provider Priority';
 
   @override
   String get lyricsProvidersDescription =>
@@ -2821,7 +2858,7 @@ class AppLocalizationsUk extends AppLocalizations {
 
   @override
   String get lyricsProvidersInfoText =>
-      'Постачальники розширених текстів пісень завжди запускаються перед вбудованими постачальниками. Принаймні один постачальник має залишатися ввімкненим.';
+      'Extension lyrics providers run before built-in lyrics providers. At least one provider must remain enabled.';
 
   @override
   String lyricsProvidersEnabledSection(int count) {
@@ -2865,6 +2902,10 @@ class AppLocalizationsUk extends AppLocalizations {
   String get lyricsProviderQqMusicDesc =>
       'QQ Music (добре для китайських пісень, через проксі)';
 
+  @override
+  String get lyricsProviderLyricsPlusDesc =>
+      'Word-by-word karaoke lyrics (Apple/Musixmatch/Spotify/QQ, via proxy)';
+
   @override
   String get lyricsProviderExtensionDesc => 'Постачальник розширень';
 
@@ -2883,11 +2924,10 @@ class AppLocalizationsUk extends AppLocalizations {
   String get safMigrationSuccess => 'Папку завантажень оновлено до режиму SAF';
 
   @override
-  String get settingsDonate => 'Пожертвувати кошти';
+  String get settingsDonate => 'Support Development';
 
   @override
-  String get settingsDonateSubtitle =>
-      'Підтримка розробки SpotiFLAC для мобільних пристроїв';
+  String get settingsDonateSubtitle => 'Buy the developer a coffee';
 
   @override
   String get tooltipLoveAll => 'Уподобати всіх';
@@ -2950,21 +2990,20 @@ class AppLocalizationsUk extends AppLocalizations {
 
   @override
   String get downloadLocationSubtitle =>
-      'Виберіть режим зберігання для завантажених файлів.';
+      'Choose where to save your downloaded tracks';
 
   @override
-  String get storageModeAppFolder => 'Папка додатку (не SAF)';
+  String get storageModeAppFolder => 'App Folder (Recommended)';
 
   @override
   String get storageModeAppFolderSubtitle =>
-      'Використовувати шлях Music/SpotiFLAC за замовчуванням';
+      'Saves to Music/SpotiFLAC by default';
 
   @override
-  String get storageModeSaf => 'Папка SAF';
+  String get storageModeSaf => 'Custom Folder (SAF)';
 
   @override
-  String get storageModeSafSubtitle =>
-      'Вибрати папку через Android Storage Access Framework';
+  String get storageModeSafSubtitle => 'Pick any folder, including SD card';
 
   @override
   String downloadFilenameDescription(
@@ -2976,73 +3015,73 @@ class AppLocalizationsUk extends AppLocalizations {
     Object track,
     Object year,
   ) {
-    return 'Налаштувати спосіб іменування ваших файлів.';
+    return 'Use $artist, $title, $album, $track, $year, $date, $disc as placeholders.';
   }
 
   @override
   String get downloadFilenameInsertTag => 'Натисніть, щоб вставити тег:';
 
   @override
-  String get downloadSeparateSinglesEnabled => 'Папки «Альбоми» та «Сингли»';
+  String get downloadSeparateSinglesEnabled =>
+      'Singles and EPs saved in a separate folder';
 
   @override
-  String get downloadSeparateSinglesDisabled => 'Всі файли в одній структурі';
+  String get downloadSeparateSinglesDisabled =>
+      'Singles and albums saved in the same folder';
 
   @override
   String get downloadArtistNameFilters => 'Фільтри імені виконавця';
 
   @override
-  String get downloadCreatePlaylistSourceFolder =>
-      'Створити папку джерела списку відтворення';
+  String get downloadCreatePlaylistSourceFolder => 'Playlist Source Folder';
 
   @override
   String get downloadCreatePlaylistSourceFolderEnabled =>
-      'Завантаження списків відтворення використовує Playlist/ плюс вашу звичайну структуру папок.';
+      'A subfolder is created for each playlist';
 
   @override
   String get downloadCreatePlaylistSourceFolderDisabled =>
-      'Завантаження списків відтворення використовують лише звичайну структуру папок.';
+      'All tracks saved directly to download folder';
 
   @override
   String get downloadCreatePlaylistSourceFolderRedundant =>
-      'За допомогою списку відтворення завантаження вже розміщуються в папці зі списком відтворення.';
+      'Handled by folder organization setting';
 
   @override
   String get downloadSongLinkRegion => 'Регіон SongLink';
 
   @override
-  String get downloadNetworkCompatibilityMode => 'Режим сумісності з мережею';
+  String get downloadNetworkCompatibilityMode => 'Network Compatibility Mode';
 
   @override
   String get downloadNetworkCompatibilityModeEnabled =>
-      'Увімкнено: спробувати HTTP + прийняти недійсні сертифікати TLS (небезпечно)';
+      'Using legacy TLS settings for older networks';
 
   @override
   String get downloadNetworkCompatibilityModeDisabled =>
-      'Вимкнено: сувора перевірка сертифіката HTTPS (рекомендовано)';
+      'Using standard network settings';
 
   @override
   String get downloadSelectServiceToEnable =>
-      'Виберіть вбудовану службу, яку потрібно ввімкнути';
+      'Select a provider with quality options to enable this option';
 
   @override
   String get downloadSelectTidalQobuz =>
-      'Виберіть Tidal або Qobuz вище, щоб налаштувати якість';
+      'Select a provider with quality options to choose audio quality';
 
   @override
-  String get downloadEmbedLyricsDisabled =>
-      'Вимкнено, якщо вимкнено функцію «Вбудувати метадані»';
+  String get downloadEmbedLyricsDisabled => 'Enable metadata embedding first';
 
   @override
   String get downloadNeteaseIncludeTranslation => 'Netease: Включити переклад';
 
   @override
   String get downloadNeteaseIncludeTranslationEnabled =>
-      'Додати перекладені тексти пісень, коли вони доступні';
+      'Chinese translation lines included';
 
   @override
   String get downloadNeteaseIncludeTranslationDisabled =>
-      'Використовувати лише оригінальні тексти пісень';
+      'Original lyrics only';
 
   @override
   String get downloadNeteaseIncludeRomanization =>
@@ -3050,67 +3089,76 @@ class AppLocalizationsUk extends AppLocalizations {
 
   @override
   String get downloadNeteaseIncludeRomanizationEnabled =>
-      'Додати романізовані тексти пісень, коли це можливо';
+      'Romanization lines included';
 
   @override
-  String get downloadNeteaseIncludeRomanizationDisabled => 'Вимкнути';
+  String get downloadNeteaseIncludeRomanizationDisabled => 'No romanization';
 
   @override
-  String get downloadAppleQqMultiPerson =>
-      'Apple/QQ Багатокористувацький переклад слово за словом';
+  String get downloadAppleQqMultiPerson => 'Apple / QQ: Multi-Person Lyrics';
 
   @override
   String get downloadAppleQqMultiPersonEnabled =>
-      'Увімкнути теги динаміка v1/v2 та [bg:]';
+      'Speaker labels included for duets and group tracks';
 
   @override
   String get downloadAppleQqMultiPersonDisabled =>
-      'Спрощене послівне форматування';
+      'Standard lyrics without speaker labels';
+
+  @override
+  String get downloadAppleElrcWordSync => 'Apple Music eLRC Word Sync';
+
+  @override
+  String get downloadAppleElrcWordSyncEnabled =>
+      'Raw word-by-word timestamps preserved';
+
+  @override
+  String get downloadAppleElrcWordSyncDisabled =>
+      'Safer line-by-line Apple Music lyrics';
 
   @override
   String get downloadMusixmatchLanguage => 'Мова Musixmatch';
 
   @override
-  String get downloadMusixmatchLanguageAuto => 'Авто (оригінал)';
+  String get downloadMusixmatchLanguageAuto => 'Auto (original language)';
 
   @override
-  String get downloadFilterContributing =>
-      'Фільтрувати виконавців-учасників у розділі «Виконавець альбому»';
+  String get downloadFilterContributing => 'Filter Contributing Artists';
 
   @override
   String get downloadFilterContributingEnabled =>
-      'Метадані виконавця альбому використовують лише основного виконавця';
+      'Contributing artists removed from Album Artist folder name';
 
   @override
   String get downloadFilterContributingDisabled =>
-      'Зберегти повне значення метаданих виконавця альбому';
+      'Full Album Artist string used';
 
   @override
-  String get downloadProvidersNoneEnabled => 'Не ввімкнено';
+  String get downloadProvidersNoneEnabled => 'No providers enabled';
 
   @override
   String get downloadMusixmatchLanguageCode => 'Код мови';
 
   @override
-  String get downloadMusixmatchLanguageHint => 'авто / en / es / ja';
+  String get downloadMusixmatchLanguageHint => 'e.g. en, de, ja';
 
   @override
   String get downloadMusixmatchLanguageDesc =>
-      'Встановити потрібний код мови (наприклад: en, es, ja). Залиште поле порожнім для автоматичного вибору.';
+      'Enter a BCP-47 language code (e.g. en, de, ja) to request translated lyrics from Musixmatch.';
 
   @override
   String get downloadMusixmatchAuto => 'Авто';
 
   @override
-  String get downloadNetworkAnySubtitle => 'Wi-Fi + мобільний інтернет';
+  String get downloadNetworkAnySubtitle => 'Use WiFi or mobile data';
 
   @override
   String get downloadNetworkWifiOnlySubtitle =>
-      'Призупинити завантаження через мобільний інтернет';
+      'Downloads pause when on mobile data';
 
   @override
   String get downloadSongLinkRegionDesc =>
-      'Використовувати як userCountry для пошуку SongLink API.';
+      'Region used when resolving track links via SongLink. Choose the country where your streaming services are available.';
 
   @override
   String get snackbarUnsupportedAudioFormat => 'Непідтримуваний аудіоформат';
@@ -3316,6 +3364,15 @@ class AppLocalizationsUk extends AppLocalizations {
   @override
   String get audioAnalysisSampleRate => 'Частота дискретизації';
 
+  @override
+  String get audioAnalysisCodec => 'Codec';
+
+  @override
+  String get audioAnalysisContainer => 'Container';
+
+  @override
+  String get audioAnalysisDecodedFormat => 'Decoded Format';
+
   @override
   String get audioAnalysisBitDepth => 'Глибина бітів';
 
@@ -3340,9 +3397,33 @@ class AppLocalizationsUk extends AppLocalizations {
   @override
   String get audioAnalysisRms => 'RMS';
 
+  @override
+  String get audioAnalysisLufs => 'LUFS';
+
+  @override
+  String get audioAnalysisTruePeak => 'True Peak';
+
+  @override
+  String get audioAnalysisClipping => 'Clipping';
+
+  @override
+  String get audioAnalysisNoClipping => 'No clipping';
+
+  @override
+  String get audioAnalysisSpectralCutoff => 'Spectral Cutoff';
+
+  @override
+  String get audioAnalysisChannelStats => 'Per-channel Stats';
+
   @override
   String get audioAnalysisSamples => 'Семпли';
 
+  @override
+  String get audioAnalysisRescan => 'Re-analyze';
+
+  @override
+  String get audioAnalysisRescanning => 'Re-analyzing audio...';
+
   @override
   String extensionsSearchWith(String providerName) {
     return 'Пошук за допомогою$providerName';
@@ -3470,7 +3551,13 @@ class AppLocalizationsUk extends AppLocalizations {
 
   @override
   String notifTracksDownloadedSuccess(int count) {
-    return '$count треки успішно завантажено';
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: '$count tracks downloaded successfully',
+      one: '1 track downloaded successfully',
+    );
+    return '$_temp0';
   }
 
   @override
@@ -3550,7 +3637,7 @@ class AppLocalizationsUk extends AppLocalizations {
 
   @override
   String notifDownloadingUpdate(String version) {
-    return 'Завантаження SpotiFLAC Mobile v$version';
+    return 'Downloading SpotiFLAC Mobile v$version';
   }
 
   @override
@@ -3563,7 +3650,7 @@ class AppLocalizationsUk extends AppLocalizations {
 
   @override
   String notifUpdateReadyBody(String version) {
-    return 'SpotiFLAC Mobile v$version завантажений. Натисніть щоб установити.';
+    return 'SpotiFLAC Mobile v$version downloaded. Tap to install.';
   }
 
   @override
@@ -3665,6 +3752,13 @@ class AppLocalizationsUk extends AppLocalizations {
   @override
   String get queueDownloadCompleted => 'Download completed';
 
+  @override
+  String get queueRateLimitTitle => 'Service rate limited';
+
+  @override
+  String get queueRateLimitMessage =>
+      'This track may still be available. Wait a few minutes, reduce parallel downloads, then retry.';
+
   @override
   String appearanceSelectAccentColor(String hex) {
     return 'Select accent color $hex';
@@ -3858,4 +3952,379 @@ class AppLocalizationsUk extends AppLocalizations {
   @override
   String get downloadFallbackExtensionsSubtitle =>
       'Choose which extensions can be used as fallback';
+
+  @override
+  String get editMetadataFieldDateHint => 'YYYY-MM-DD or YYYY';
+
+  @override
+  String get editMetadataFieldTrackTotal => 'Track Total';
+
+  @override
+  String get editMetadataFieldDiscTotal => 'Disc Total';
+
+  @override
+  String get editMetadataFieldComposer => 'Composer';
+
+  @override
+  String get editMetadataFieldComment => 'Comment';
+
+  @override
+  String get editMetadataAdvanced => 'Advanced';
+
+  @override
+  String get libraryFilterMetadataMissingTrackNumber => 'Missing track number';
+
+  @override
+  String get libraryFilterMetadataMissingDiscNumber => 'Missing disc number';
+
+  @override
+  String get libraryFilterMetadataMissingArtist => 'Missing artist';
+
+  @override
+  String get libraryFilterMetadataIncorrectIsrcFormat =>
+      'Incorrect ISRC format';
+
+  @override
+  String get libraryFilterMetadataMissingLabel => 'Missing label';
+
+  @override
+  String collectionDeletePlaylistsMessage(int count) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'playlists',
+      one: 'playlist',
+    );
+    return 'Delete $count $_temp0?';
+  }
+
+  @override
+  String collectionPlaylistsDeleted(int count) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'playlists',
+      one: 'playlist',
+    );
+    return '$count $_temp0 deleted';
+  }
+
+  @override
+  String collectionAddedTracksToPlaylist(int count, String playlistName) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'tracks',
+      one: 'track',
+    );
+    return 'Added $count $_temp0 to $playlistName';
+  }
+
+  @override
+  String collectionAddedTracksToPlaylistWithExisting(
+    int count,
+    String playlistName,
+    int alreadyCount,
+  ) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'tracks',
+      one: 'track',
+    );
+    return 'Added $count $_temp0 to $playlistName ($alreadyCount already in playlist)';
+  }
+
+  @override
+  String itemCount(int count) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'items',
+      one: 'item',
+    );
+    return '$count $_temp0';
+  }
+
+  @override
+  String trackReEnrichSuccessWithFailures(
+    int successCount,
+    int total,
+    int failedCount,
+  ) {
+    return 'Metadata re-enriched successfully ($successCount/$total) - Failed: $failedCount';
+  }
+
+  @override
+  String selectionDeleteTracksCount(int count) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'tracks',
+      one: 'track',
+    );
+    return 'Delete $count $_temp0';
+  }
+
+  @override
+  String queueDownloadSpeedStatus(String speed) {
+    return 'Downloading - $speed MB/s';
+  }
+
+  @override
+  String get queueDownloadStarting => 'Starting...';
+
+  @override
+  String get a11ySelectTrack => 'Select track';
+
+  @override
+  String get a11yDeselectTrack => 'Deselect track';
+
+  @override
+  String a11yPlayTrackByArtist(String trackName, String artistName) {
+    return 'Play $trackName by $artistName';
+  }
+
+  @override
+  String storeExtensionsCount(int count) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'extensions',
+      one: 'extension',
+    );
+    return '$count $_temp0';
+  }
+
+  @override
+  String storeRequiresVersion(String version) {
+    return 'Requires v$version+';
+  }
+
+  @override
+  String get actionGo => 'Go';
+
+  @override
+  String get logIssueSummary => 'Issue Summary';
+
+  @override
+  String logTotalErrors(int count) {
+    return 'Total errors: $count';
+  }
+
+  @override
+  String logAffectedDomains(String domains) {
+    return 'Affected: $domains';
+  }
+
+  @override
+  String get libraryScanCancelled => 'Scan cancelled';
+
+  @override
+  String get libraryScanCancelledSubtitle =>
+      'You can retry the scan when ready.';
+
+  @override
+  String libraryDownloadsHistoryExcluded(int count) {
+    return '$count from Downloads history (excluded from list)';
+  }
+
+  @override
+  String get downloadNativeWorker => 'Native download worker';
+
+  @override
+  String get downloadNativeWorkerSubtitle =>
+      'Beta Android service worker for extension downloads';
+
+  @override
+  String get badgeBeta => 'BETA';
+
+  @override
+  String get extensionServiceStatus => 'Service Status';
+
+  @override
+  String get extensionServiceHealth => 'Service health';
+
+  @override
+  String extensionHealthChecksConfigured(int count) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'checks',
+      one: 'check',
+    );
+    return '$count $_temp0 configured';
+  }
+
+  @override
+  String get extensionOauthConnectHint =>
+      'Tap Connect to Spotify to fill this field.';
+
+  @override
+  String extensionLastChecked(String time) {
+    return 'Last checked $time';
+  }
+
+  @override
+  String get extensionRefreshStatus => 'Refresh status';
+
+  @override
+  String get extensionCustomUrlHandling => 'Custom URL Handling';
+
+  @override
+  String get extensionCustomUrlHandlingSubtitle =>
+      'This extension can handle links from these sites';
+
+  @override
+  String get extensionCustomUrlHandlingShareHint =>
+      'Share links from these sites to SpotiFLAC Mobile and this extension will handle them.';
+
+  @override
+  String extensionSettingsCount(int count) {
+    String _temp0 = intl.Intl.pluralLogic(
+      count,
+      locale: localeName,
+      other: 'settings',
+      one: 'setting',
+    );
+    return '$count $_temp0';
+  }
+
+  @override
+  String get extensionHealthOnline => 'Online';
+
+  @override
+  String get extensionHealthDegraded => 'Degraded';
+
+  @override
+  String get extensionHealthOffline => 'Offline';
+
+  @override
+  String get extensionHealthNotConfigured => 'Not configured';
+
+  @override
+  String get extensionHealthUnknown => 'Unknown';
+
+  @override
+  String get extensionHealthRequired => 'required';
+
+  @override
+  String get extensionSettingNotSet => 'Not set';
+
+  @override
+  String get extensionActionFailed => 'Action failed';
+
+  @override
+  String get extensionEnterValue => 'Enter value';
+
+  @override
+  String get extensionHealthServiceOnline => 'Service online';
+
+  @override
+  String get extensionHealthServiceDegraded => 'Service degraded';
+
+  @override
+  String get extensionHealthServiceOffline => 'Service offline';
+
+  @override
+  String get extensionHealthServiceUnknown => 'Service status unknown';
+
+  @override
+  String get audioAnalysisStereo => 'Stereo';
+
+  @override
+  String get audioAnalysisMono => 'Mono';
+
+  @override
+  String trackOpenInService(String serviceName) {
+    return 'Open in $serviceName';
+  }
+
+  @override
+  String get trackLyricsEmbeddedSource => 'Embedded';
+
+  @override
+  String get unknownAlbum => 'Unknown Album';
+
+  @override
+  String get unknownArtist => 'Unknown Artist';
+
+  @override
+  String get permissionAudio => 'Audio';
+
+  @override
+  String get permissionStorage => 'Storage';
+
+  @override
+  String get permissionNotification => 'Notification';
+
+  @override
+  String get errorInvalidFolderSelected => 'Invalid folder selected';
+
+  @override
+  String get errorCouldNotKeepFolderAccess =>
+      'Could not keep access to the selected folder';
+
+  @override
+  String get storeAnyVersion => 'Any';
+
+  @override
+  String get storeCategoryMetadata => 'Metadata';
+
+  @override
+  String get storeCategoryDownload => 'Download';
+
+  @override
+  String get storeCategoryUtility => 'Utility';
+
+  @override
+  String get storeCategoryLyrics => 'Lyrics';
+
+  @override
+  String get storeCategoryIntegration => 'Integration';
+
+  @override
+  String get artistReleases => 'Releases';
+
+  @override
+  String get editMetadataSelectNone => 'None';
+
+  @override
+  String queueRetryAllFailed(int count) {
+    return 'Retry $count failed';
+  }
+
+  @override
+  String get settingsSaveDownloadHistory => 'Save download history';
+
+  @override
+  String get settingsSaveDownloadHistorySubtitle =>
+      'Keep completed downloads in history and library views';
+
+  @override
+  String get dialogDisableHistoryTitle => 'Turn off download history?';
+
+  @override
+  String get dialogDisableHistoryMessage =>
+      'Existing history will be cleared. Downloaded files will not be deleted.';
+
+  @override
+  String get dialogDisableAndClear => 'Turn off and clear';
+
+  @override
+  String get openInOtherServices => 'Open in Other Services';
+
+  @override
+  String get shareSheetNoExtensions => 'No other compatible services';
+
+  @override
+  String get shareSheetNotFound => 'Not found';
+
+  @override
+  String get shareSheetCopyLink => 'Copy Link';
+
+  @override
+  String shareSheetLinkCopied(Object service) {
+    return '$service link copied';
+  }
 }

lib/l10n/arb/app_en.arb

@@ -174,9 +174,9 @@
   "@optionsDefaultSearchTabSubtitle": {
     "description": "Subtitle for the preferred default search tab setting"
   },
-  "optionsSwitchBack": "Tap Deezer or Spotify to switch back from extension",
+  "optionsSwitchBack": "Choose the default search provider to switch back from an extension",
   "@optionsSwitchBack": {
-    "description": "Hint to switch back to built-in providers"
+    "description": "Hint to switch back from extension search"
   },
   "optionsAutoFallback": "Auto Fallback",
   "@optionsAutoFallback": {
@@ -188,15 +188,15 @@
   },
   "optionsUseExtensionProviders": "Use Extension Providers",
   "@optionsUseExtensionProviders": {
-    "description": "Enable extension download providers"
+    "description": "Legacy setting label for extension download providers"
   },
-  "optionsUseExtensionProvidersOn": "Extensions will be tried first",
+  "optionsUseExtensionProvidersOn": "Extension providers are enabled",
   "@optionsUseExtensionProvidersOn": {
     "description": "Status when extension providers enabled"
   },
-  "optionsUseExtensionProvidersOff": "Using built-in providers only",
+  "optionsUseExtensionProvidersOff": "Extension providers are required",
   "@optionsUseExtensionProvidersOff": {
-    "description": "Status when extension providers disabled"
+    "description": "Legacy status when extension providers would be disabled"
   },
   "optionsEmbedLyrics": "Embed Lyrics",
   "@optionsEmbedLyrics": {
@@ -226,6 +226,64 @@
   "@optionsReplayGainSubtitleOff": {
     "description": "Subtitle when ReplayGain is disabled"
   },
+  "trackReplayGain": "Rescan ReplayGain",
+  "@trackReplayGain": {
+    "description": "Three-dot menu option to scan loudness and write ReplayGain tags"
+  },
+  "trackReplayGainSubtitle": "Analyze loudness and write ReplayGain tags",
+  "@trackReplayGainSubtitle": {
+    "description": "Subtitle for the rescan ReplayGain menu option"
+  },
+  "trackReplayGainScanning": "Analyzing loudness...",
+  "@trackReplayGainScanning": {
+    "description": "Snackbar/progress message while scanning ReplayGain for a single track"
+  },
+  "trackReplayGainSuccess": "ReplayGain tags added",
+  "@trackReplayGainSuccess": {
+    "description": "Snackbar message after ReplayGain tags written for a single track"
+  },
+  "trackReplayGainFailed": "Failed to add ReplayGain tags",
+  "@trackReplayGainFailed": {
+    "description": "Snackbar message when ReplayGain scan/write fails"
+  },
+  "selectionReplayGainCount": "ReplayGain ({count})",
+  "@selectionReplayGainCount": {
+    "description": "Batch selection action button label for ReplayGain",
+    "placeholders": {
+      "count": {
+        "type": "int"
+      }
+    }
+  },
+  "replayGainBatchConfirmTitle": "Add ReplayGain",
+  "@replayGainBatchConfirmTitle": {
+    "description": "Title of the batch ReplayGain confirmation dialog"
+  },
+  "replayGainBatchConfirmMessage": "Analyze loudness and write ReplayGain tags to {count} track(s)?",
+  "@replayGainBatchConfirmMessage": {
+    "description": "Message of the batch ReplayGain confirmation dialog",
+    "placeholders": {
+      "count": {
+        "type": "int"
+      }
+    }
+  },
+  "replayGainBatchAnalyzing": "Analyzing ReplayGain...",
+  "@replayGainBatchAnalyzing": {
+    "description": "Progress dialog title while batch scanning ReplayGain"
+  },
+  "replayGainBatchSuccess": "ReplayGain added to {success} of {total} tracks",
+  "@replayGainBatchSuccess": {
+    "description": "Snackbar after batch ReplayGain completes",
+    "placeholders": {
+      "success": {
+        "type": "int"
+      },
+      "total": {
+        "type": "int"
+      }
+    }
+  },
   "optionsArtistTagMode": "Artist Tag Mode",
   "@optionsArtistTagMode": {
     "description": "Setting title for how artist metadata is written into files"
@@ -250,27 +308,6 @@
   "@optionsArtistTagModeSplitVorbisSubtitle": {
     "description": "Subtitle for split Vorbis artist tag mode"
   },
-  "optionsConcurrentDownloads": "Concurrent Downloads",
-  "@optionsConcurrentDownloads": {
-    "description": "Number of parallel downloads"
-  },
-  "optionsConcurrentSequential": "Sequential (1 at a time)",
-  "@optionsConcurrentSequential": {
-    "description": "Download one at a time"
-  },
-  "optionsConcurrentParallel": "{count} parallel downloads",
-  "@optionsConcurrentParallel": {
-    "description": "Multiple parallel downloads",
-    "placeholders": {
-      "count": {
-        "type": "int"
-      }
-    }
-  },
-  "optionsConcurrentWarning": "Parallel downloads may trigger rate limiting",
-  "@optionsConcurrentWarning": {
-    "description": "Warning about rate limits"
-  },
   "optionsExtensionStore": "Extension Repo",
   "@optionsExtensionStore": {
     "description": "Show/hide store tab"
@@ -486,11 +523,11 @@
   "@aboutVersion": {
     "description": "Version info label"
   },
-  "aboutBinimumDesc": "The creator of QQDL & HiFi API. Without this API, Tidal downloads wouldn't exist!",
+  "aboutBinimumDesc": "The creator of QQDL & HiFi API. This project helped shape lossless download support.",
   "@aboutBinimumDesc": {
     "description": "Credit description for binimum"
   },
-  "aboutSachinsenalDesc": "The original HiFi project creator. The foundation of Tidal integration!",
+  "aboutSachinsenalDesc": "The original HiFi project creator. A foundation for lossless-source integration.",
   "@aboutSachinsenalDesc": {
     "description": "Credit description for sachinsenal0x64"
   },
@@ -498,7 +535,7 @@
   "@aboutSjdonadoDesc": {
     "description": "Credit description for sjdonado"
   },
-  "aboutAppDescription": "Download Spotify tracks in lossless quality from Tidal and Qobuz.",
+  "aboutAppDescription": "Search music metadata, manage extensions, and organize your library.",
   "@aboutAppDescription": {
     "description": "App description in header card"
   },
@@ -961,6 +998,10 @@
   "@errorNoTracksFound": {
     "description": "Error - search returned no results"
   },
+  "searchEmptyResultSubtitle": "Try another keyword",
+  "@searchEmptyResultSubtitle": {
+    "description": "Subtitle shown under the empty search result state on the home screen"
+  },
   "errorUrlNotRecognized": "Link not recognized",
   "@errorUrlNotRecognized": {
     "description": "Error title - URL not handled by any extension or service"
@@ -1231,9 +1272,9 @@
   "@providerPriorityFallbackExtensionsHint": {
     "description": "Hint below the extension fallback selection list"
   },
-  "providerBuiltIn": "Built-in",
+  "providerBuiltIn": "Legacy",
   "@providerBuiltIn": {
-    "description": "Label for built-in providers (Tidal/Qobuz)"
+    "description": "Legacy label retained for old generated localization compatibility"
   },
   "providerExtension": "Extension",
   "@providerExtension": {
@@ -1587,6 +1628,15 @@
   "@trackCopyLyrics": {
     "description": "Action - copy lyrics to clipboard"
   },
+  "trackLyricsSource": "Source: {source}",
+  "@trackLyricsSource": {
+    "description": "Label showing the lyrics source/provider",
+    "placeholders": {
+      "source": {
+        "type": "String"
+      }
+    }
+  },
   "trackLyricsNotAvailable": "Lyrics not available for this track",
   "@trackLyricsNotAvailable": {
     "description": "Message when lyrics not found"
@@ -1746,11 +1796,11 @@
   "@storeEmptyNoResults": {
     "description": "Message when search/filter returns no results"
   },
-  "extensionDefaultProvider": "Default (Deezer)",
+  "extensionDefaultProvider": "Default Search",
   "@extensionDefaultProvider": {
     "description": "Default search provider option"
   },
-  "extensionDefaultProviderSubtitle": "Use built-in search",
+  "extensionDefaultProviderSubtitle": "Use the default metadata search",
   "@extensionDefaultProviderSubtitle": {
     "description": "Subtitle for default provider"
   },
@@ -1979,43 +2029,51 @@
   },
   "downloadLossy320": "Lossy 320kbps",
   "@downloadLossy320": {
-    "description": "Quality option label for Tidal lossy 320kbps"
+    "description": "Quality option label for lossy 320kbps"
   },
   "downloadLossyFormat": "Lossy Format",
   "@downloadLossyFormat": {
-    "description": "Setting title to pick output format for Tidal lossy downloads"
+    "description": "Setting title to pick output format for lossy downloads"
   },
   "downloadLossy320Format": "Lossy 320kbps Format",
   "@downloadLossy320Format": {
-    "description": "Title of the Tidal lossy format picker bottom sheet"
+    "description": "Title of the lossy format picker bottom sheet"
   },
-  "downloadLossy320FormatDesc": "Choose the output format for Tidal 320kbps lossy downloads. The original AAC stream will be converted to your selected format.",
+  "downloadLossy320FormatDesc": "Choose the output format for 320kbps lossy downloads. The original stream will be converted to your selected format when needed.",
   "@downloadLossy320FormatDesc": {
-    "description": "Description in the Tidal lossy format picker"
+    "description": "Description in the lossy format picker"
   },
   "downloadLossyMp3": "MP3 320kbps",
   "@downloadLossyMp3": {
-    "description": "Tidal lossy format option - MP3 320kbps"
+    "description": "Lossy format option - MP3 320kbps"
   },
   "downloadLossyMp3Subtitle": "Best compatibility, ~10MB per track",
   "@downloadLossyMp3Subtitle": {
-    "description": "Subtitle for MP3 320kbps Tidal lossy option"
+    "description": "Subtitle for MP3 320kbps lossy option"
+  },
+  "downloadLossyAac": "AAC/M4A 320kbps",
+  "@downloadLossyAac": {
+    "description": "Lossy format option - AAC in M4A container at 320kbps"
+  },
+  "downloadLossyAacSubtitle": "Best mobile compatibility, M4A container",
+  "@downloadLossyAacSubtitle": {
+    "description": "Subtitle for AAC/M4A 320kbps lossy option"
   },
   "downloadLossyOpus256": "Opus 256kbps",
   "@downloadLossyOpus256": {
-    "description": "Tidal lossy format option - Opus 256kbps"
+    "description": "Lossy format option - Opus 256kbps"
   },
   "downloadLossyOpus256Subtitle": "Best quality Opus, ~8MB per track",
   "@downloadLossyOpus256Subtitle": {
-    "description": "Subtitle for Opus 256kbps Tidal lossy option"
+    "description": "Subtitle for Opus 256kbps lossy option"
   },
   "downloadLossyOpus128": "Opus 128kbps",
   "@downloadLossyOpus128": {
-    "description": "Tidal lossy format option - Opus 128kbps"
+    "description": "Lossy format option - Opus 128kbps"
   },
   "downloadLossyOpus128Subtitle": "Smallest size, ~4MB per track",
   "@downloadLossyOpus128Subtitle": {
-    "description": "Subtitle for Opus 128kbps Tidal lossy option"
+    "description": "Subtitle for Opus 128kbps lossy option"
   },
   "qualityNote": "Actual quality depends on track availability from the service",
   "@qualityNote": {
@@ -2498,7 +2556,7 @@
   "@libraryAbout": {
     "description": "Section header for about info"
   },
-  "libraryAboutDescription": "Scans your existing music collection to detect duplicates when downloading. Supports FLAC, M4A, MP3, Opus, and OGG formats. Metadata is read from file tags when available.",
+  "libraryAboutDescription": "Scans your existing music collection to detect duplicates when downloading. Supports FLAC, ALAC, M4A, MP3, Opus, OGG, WAV, AIFF, and APE formats. Metadata is read from file tags when available.",
   "@libraryAboutDescription": {
     "description": "Description of local library feature"
   },
@@ -2724,7 +2782,7 @@
   "@tutorialWelcomeTip1": {
     "description": "Tutorial welcome tip 1"
   },
-  "tutorialWelcomeTip2": "Get FLAC quality audio from Tidal, Qobuz, or Deezer",
+  "tutorialWelcomeTip2": "Get FLAC quality audio from installed download extensions",
   "@tutorialWelcomeTip2": {
     "description": "Tutorial welcome tip 2"
   },
@@ -3170,7 +3228,7 @@
   "@trackConvertFormat": {
     "description": "Menu item - convert audio format"
   },
-  "trackConvertFormatSubtitle": "Convert to MP3, Opus, ALAC, or FLAC",
+  "trackConvertFormatSubtitle": "Convert to AAC/M4A, MP3, Opus, ALAC, or FLAC",
   "@trackConvertFormatSubtitle": {
     "description": "Subtitle for convert format menu item"
   },
@@ -3683,7 +3741,7 @@
   "@lyricsProvidersDescription": {
     "description": "Description on the lyrics provider priority page"
   },
-  "lyricsProvidersInfoText": "Extension lyrics providers always run before built-in providers. At least one provider must remain enabled.",
+  "lyricsProvidersInfoText": "Extension lyrics providers run before built-in lyrics providers. At least one provider must remain enabled.",
   "@lyricsProvidersInfoText": {
     "description": "Info tip on lyrics provider priority page"
   },
@@ -3737,6 +3795,10 @@
   "@lyricsProviderQqMusicDesc": {
     "description": "Description for QQ Music provider"
   },
+  "lyricsProviderLyricsPlusDesc": "Word-by-word karaoke lyrics (Apple/Musixmatch/Spotify/QQ, via proxy)",
+  "@lyricsProviderLyricsPlusDesc": {
+    "description": "Description for LyricsPlus provider"
+  },
   "lyricsProviderExtensionDesc": "Extension provider",
   "@lyricsProviderExtensionDesc": {
     "description": "Generic description for extension-based lyrics providers"
@@ -3921,13 +3983,13 @@
   "@downloadNetworkCompatibilityModeDisabled": {
     "description": "Subtitle when network compatibility mode is off"
   },
-  "downloadSelectServiceToEnable": "Select Tidal or Qobuz to enable this option",
+  "downloadSelectServiceToEnable": "Select a provider with quality options to enable this option",
   "@downloadSelectServiceToEnable": {
     "description": "Subtitle when quality picker is disabled due to extension service"
   },
-  "downloadSelectTidalQobuz": "Select Tidal or Qobuz to choose audio quality",
+  "downloadSelectTidalQobuz": "Select a provider with quality options to choose audio quality",
   "@downloadSelectTidalQobuz": {
-    "description": "Info shown when a non-built-in service is selected"
+    "description": "Legacy info shown when a provider does not expose quality options"
   },
   "downloadEmbedLyricsDisabled": "Enable metadata embedding first",
   "@downloadEmbedLyricsDisabled": {
@@ -3969,6 +4031,18 @@
   "@downloadAppleQqMultiPersonDisabled": {
     "description": "Subtitle when multi-person lyrics is off"
   },
+  "downloadAppleElrcWordSync": "Apple Music eLRC Word Sync",
+  "@downloadAppleElrcWordSync": {
+    "description": "Setting for preserving Apple Music word-by-word eLRC timestamps"
+  },
+  "downloadAppleElrcWordSyncEnabled": "Raw word-by-word timestamps preserved",
+  "@downloadAppleElrcWordSyncEnabled": {
+    "description": "Subtitle when Apple Music eLRC word sync is enabled"
+  },
+  "downloadAppleElrcWordSyncDisabled": "Safer line-by-line Apple Music lyrics",
+  "@downloadAppleElrcWordSyncDisabled": {
+    "description": "Subtitle when Apple Music eLRC word sync is disabled"
+  },
   "downloadMusixmatchLanguage": "Musixmatch Language",
   "@downloadMusixmatchLanguage": {
     "description": "Setting for Musixmatch lyrics translation language"
@@ -4243,6 +4317,18 @@
   "@audioAnalysisSampleRate": {
     "description": "Sample rate metric label"
   },
+  "audioAnalysisCodec": "Codec",
+  "@audioAnalysisCodec": {
+    "description": "Audio codec metric label"
+  },
+  "audioAnalysisContainer": "Container",
+  "@audioAnalysisContainer": {
+    "description": "Audio container metric label"
+  },
+  "audioAnalysisDecodedFormat": "Decoded Format",
+  "@audioAnalysisDecodedFormat": {
+    "description": "Decoded sample format metric label"
+  },
   "audioAnalysisBitDepth": "Bit Depth",
   "@audioAnalysisBitDepth": {
     "description": "Bit depth metric label"
@@ -4275,13 +4361,45 @@
   "@audioAnalysisRms": {
     "description": "RMS level metric label"
   },
+  "audioAnalysisLufs": "LUFS",
+  "@audioAnalysisLufs": {
+    "description": "Integrated loudness metric label"
+  },
+  "audioAnalysisTruePeak": "True Peak",
+  "@audioAnalysisTruePeak": {
+    "description": "True peak metric label"
+  },
+  "audioAnalysisClipping": "Clipping",
+  "@audioAnalysisClipping": {
+    "description": "Clipping metric label"
+  },
+  "audioAnalysisNoClipping": "No clipping",
+  "@audioAnalysisNoClipping": {
+    "description": "Displayed when no clipped samples were detected"
+  },
+  "audioAnalysisSpectralCutoff": "Spectral Cutoff",
+  "@audioAnalysisSpectralCutoff": {
+    "description": "Estimated spectral cutoff metric label"
+  },
+  "audioAnalysisChannelStats": "Per-channel Stats",
+  "@audioAnalysisChannelStats": {
+    "description": "Per-channel audio analysis section label"
+  },
   "audioAnalysisSamples": "Samples",
   "@audioAnalysisSamples": {
     "description": "Total samples metric label"
   },
+  "audioAnalysisRescan": "Re-analyze",
+  "@audioAnalysisRescan": {
+    "description": "Tooltip/label for the button that re-runs the audio analysis, discarding cached results"
+  },
+  "audioAnalysisRescanning": "Re-analyzing audio...", 
+  "@audioAnalysisRescanning": {
+    "description": "Loading text while audio is being re-analyzed after an explicit refresh"
+  },
   "extensionsSearchWith": "Search with {providerName}",
   "@extensionsSearchWith": {
-    "description": "Extensions page - subtitle for built-in search provider option",
+    "description": "Extensions page - subtitle for default metadata search provider option",
     "placeholders": {
       "providerName": {
         "type": "String"
@@ -4735,6 +4853,14 @@
   "@queueDownloadCompleted": {
     "description": "Accessibility label for completed download state in queue"
   },
+  "queueRateLimitTitle": "Service rate limited",
+  "@queueRateLimitTitle": {
+    "description": "Title shown on a failed queue item when the download service rate limits requests"
+  },
+  "queueRateLimitMessage": "This track may still be available. Wait a few minutes, reduce parallel downloads, then retry.",
+  "@queueRateLimitMessage": {
+    "description": "Explanation shown on a failed queue item when the download service rate limits requests"
+  },
   "appearanceSelectAccentColor": "Select accent color {hex}",
   "@appearanceSelectAccentColor": {
     "description": "Accessibility label for picking an accent color",
@@ -5001,5 +5127,473 @@
   "downloadFallbackExtensionsSubtitle": "Choose which extensions can be used as fallback",
   "@downloadFallbackExtensionsSubtitle": {
     "description": "Subtitle for fallback extensions item"
+  },
+  "editMetadataFieldDateHint": "YYYY-MM-DD or YYYY",
+  "@editMetadataFieldDateHint": {
+    "description": "Hint text for the edit metadata date field"
+  },
+  "editMetadataFieldTrackTotal": "Track Total",
+  "@editMetadataFieldTrackTotal": {
+    "description": "Label for total tracks field in the edit metadata sheet"
+  },
+  "editMetadataFieldDiscTotal": "Disc Total",
+  "@editMetadataFieldDiscTotal": {
+    "description": "Label for total discs field in the edit metadata sheet"
+  },
+  "editMetadataFieldComposer": "Composer",
+  "@editMetadataFieldComposer": {
+    "description": "Label for composer field in the edit metadata sheet"
+  },
+  "editMetadataFieldComment": "Comment",
+  "@editMetadataFieldComment": {
+    "description": "Label for comment field in the edit metadata sheet"
+  },
+  "editMetadataAdvanced": "Advanced",
+  "@editMetadataAdvanced": {
+    "description": "Expandable section label for advanced metadata fields"
+  },
+  "libraryFilterMetadataMissingTrackNumber": "Missing track number",
+  "@libraryFilterMetadataMissingTrackNumber": {
+    "description": "Filter option - items missing track number"
+  },
+  "libraryFilterMetadataMissingDiscNumber": "Missing disc number",
+  "@libraryFilterMetadataMissingDiscNumber": {
+    "description": "Filter option - items missing disc number"
+  },
+  "libraryFilterMetadataMissingArtist": "Missing artist",
+  "@libraryFilterMetadataMissingArtist": {
+    "description": "Filter option - items missing artist"
+  },
+  "libraryFilterMetadataIncorrectIsrcFormat": "Incorrect ISRC format",
+  "@libraryFilterMetadataIncorrectIsrcFormat": {
+    "description": "Filter option - items with an invalid ISRC format"
+  },
+  "libraryFilterMetadataMissingLabel": "Missing label",
+  "@libraryFilterMetadataMissingLabel": {
+    "description": "Filter option - items missing record label"
+  },
+  "collectionDeletePlaylistsMessage": "Delete {count} {count, plural, =1{playlist} other{playlists}}?",
+  "@collectionDeletePlaylistsMessage": {
+    "description": "Confirmation message for deleting selected playlists",
+    "placeholders": {
+      "count": {
+        "type": "int"
+      }
+    }
+  },
+  "collectionPlaylistsDeleted": "{count} {count, plural, =1{playlist} other{playlists}} deleted",
+  "@collectionPlaylistsDeleted": {
+    "description": "Snackbar after deleting selected playlists",
+    "placeholders": {
+      "count": {
+        "type": "int"
+      }
+    }
+  },
+  "collectionAddedTracksToPlaylist": "Added {count} {count, plural, =1{track} other{tracks}} to {playlistName}",
+  "@collectionAddedTracksToPlaylist": {
+    "description": "Snackbar after adding multiple tracks to a playlist",
+    "placeholders": {
+      "count": {
+        "type": "int"
+      },
+      "playlistName": {
+        "type": "String"
+      }
+    }
+  },
+  "collectionAddedTracksToPlaylistWithExisting": "Added {count} {count, plural, =1{track} other{tracks}} to {playlistName} ({alreadyCount} already in playlist)",
+  "@collectionAddedTracksToPlaylistWithExisting": {
+    "description": "Snackbar after adding multiple tracks to a playlist when some were already present",
+    "placeholders": {
+      "count": {
+        "type": "int"
+      },
+      "playlistName": {
+        "type": "String"
+      },
+      "alreadyCount": {
+        "type": "int"
+      }
+    }
+  },
+  "itemCount": "{count} {count, plural, =1{item} other{items}}",
+  "@itemCount": {
+    "description": "Generic item count label",
+    "placeholders": {
+      "count": {
+        "type": "int"
+      }
+    }
+  },
+  "trackReEnrichSuccessWithFailures": "Metadata re-enriched successfully ({successCount}/{total}) - Failed: {failedCount}",
+  "@trackReEnrichSuccessWithFailures": {
+    "description": "Snackbar summary after batch metadata re-enrichment finishes with failures",
+    "placeholders": {
+      "successCount": {
+        "type": "int"
+      },
+      "total": {
+        "type": "int"
+      },
+      "failedCount": {
+        "type": "int"
+      }
+    }
+  },
+  "selectionDeleteTracksCount": "Delete {count} {count, plural, =1{track} other{tracks}}",
+  "@selectionDeleteTracksCount": {
+    "description": "Button label for deleting selected tracks",
+    "placeholders": {
+      "count": {
+        "type": "int"
+      }
+    }
+  },
+  "queueDownloadSpeedStatus": "Downloading - {speed} MB/s",
+  "@queueDownloadSpeedStatus": {
+    "description": "Queue status while downloading with speed",
+    "placeholders": {
+      "speed": {
+        "type": "String"
+      }
+    }
+  },
+  "queueDownloadStarting": "Starting...",
+  "@queueDownloadStarting": {
+    "description": "Queue status before download progress is available"
+  },
+  "a11ySelectTrack": "Select track",
+  "@a11ySelectTrack": {
+    "description": "Accessibility label for selecting a track"
+  },
+  "a11yDeselectTrack": "Deselect track",
+  "@a11yDeselectTrack": {
+    "description": "Accessibility label for deselecting a track"
+  },
+  "a11yPlayTrackByArtist": "Play {trackName} by {artistName}",
+  "@a11yPlayTrackByArtist": {
+    "description": "Accessibility label for playing a local library track",
+    "placeholders": {
+      "trackName": {
+        "type": "String"
+      },
+      "artistName": {
+        "type": "String"
+      }
+    }
+  },
+  "storeExtensionsCount": "{count} {count, plural, =1{extension} other{extensions}}",
+  "@storeExtensionsCount": {
+    "description": "Store extension result count",
+    "placeholders": {
+      "count": {
+        "type": "int"
+      }
+    }
+  },
+  "storeRequiresVersion": "Requires v{version}+",
+  "@storeRequiresVersion": {
+    "description": "Store compatibility badge for minimum app version",
+    "placeholders": {
+      "version": {
+        "type": "String"
+      }
+    }
+  },
+  "actionGo": "Go",
+  "@actionGo": {
+    "description": "Generic action button label"
+  },
+  "logIssueSummary": "Issue Summary",
+  "@logIssueSummary": {
+    "description": "Header for log issue analysis summary"
+  },
+  "logTotalErrors": "Total errors: {count}",
+  "@logTotalErrors": {
+    "description": "Total error count in log issue analysis",
+    "placeholders": {
+      "count": {
+        "type": "int"
+      }
+    }
+  },
+  "logAffectedDomains": "Affected: {domains}",
+  "@logAffectedDomains": {
+    "description": "Affected domains in log issue analysis",
+    "placeholders": {
+      "domains": {
+        "type": "String"
+      }
+    }
+  },
+  "libraryScanCancelled": "Scan cancelled",
+  "@libraryScanCancelled": {
+    "description": "Library scan status when a scan was cancelled"
+  },
+  "libraryScanCancelledSubtitle": "You can retry the scan when ready.",
+  "@libraryScanCancelledSubtitle": {
+    "description": "Library scan status subtitle after cancellation"
+  },
+  "libraryDownloadsHistoryExcluded": "{count} from Downloads history (excluded from list)",
+  "@libraryDownloadsHistoryExcluded": {
+    "description": "Library count note for downloaded history items excluded from the local list",
+    "placeholders": {
+      "count": {
+        "type": "int"
+      }
+    }
+  },
+  "downloadNativeWorker": "Native download worker",
+  "@downloadNativeWorker": {
+    "description": "Setting title for Android native download worker"
+  },
+  "downloadNativeWorkerSubtitle": "Beta Android service worker for extension downloads",
+  "@downloadNativeWorkerSubtitle": {
+    "description": "Setting subtitle for Android native download worker"
+  },
+  "badgeBeta": "BETA",
+  "@badgeBeta": {
+    "description": "Badge label for beta features"
+  },
+  "extensionServiceStatus": "Service Status",
+  "@extensionServiceStatus": {
+    "description": "Extension detail section header for service status"
+  },
+  "extensionServiceHealth": "Service health",
+  "@extensionServiceHealth": {
+    "description": "Extension capability label for service health checks"
+  },
+  "extensionHealthChecksConfigured": "{count} {count, plural, =1{check} other{checks}} configured",
+  "@extensionHealthChecksConfigured": {
+    "description": "Extension service health check count",
+    "placeholders": {
+      "count": {
+        "type": "int"
+      }
+    }
+  },
+  "extensionOauthConnectHint": "Tap Connect to Spotify to fill this field.",
+  "@extensionOauthConnectHint": {
+    "description": "Hint for an OAuth login link field before connecting Spotify"
+  },
+  "extensionLastChecked": "Last checked {time}",
+  "@extensionLastChecked": {
+    "description": "Timestamp for the latest extension service health check",
+    "placeholders": {
+      "time": {
+        "type": "String"
+      }
+    }
+  },
+  "extensionRefreshStatus": "Refresh status",
+  "@extensionRefreshStatus": {
+    "description": "Tooltip for refreshing extension service health status"
+  },
+  "extensionCustomUrlHandling": "Custom URL Handling",
+  "@extensionCustomUrlHandling": {
+    "description": "Extension detail section title for custom URL handling"
+  },
+  "extensionCustomUrlHandlingSubtitle": "This extension can handle links from these sites",
+  "@extensionCustomUrlHandlingSubtitle": {
+    "description": "Extension detail subtitle for custom URL handling"
+  },
+  "extensionCustomUrlHandlingShareHint": "Share links from these sites to SpotiFLAC Mobile and this extension will handle them.",
+  "@extensionCustomUrlHandlingShareHint": {
+    "description": "Extension detail hint explaining share-to-app URL handling"
+  },
+  "extensionSettingsCount": "{count} {count, plural, =1{setting} other{settings}}",
+  "@extensionSettingsCount": {
+    "description": "Count of settings exposed by an extension quality option",
+    "placeholders": {
+      "count": {
+        "type": "int"
+      }
+    }
+  },
+  "extensionHealthOnline": "Online",
+  "@extensionHealthOnline": {
+    "description": "Extension service health status - online"
+  },
+  "extensionHealthDegraded": "Degraded",
+  "@extensionHealthDegraded": {
+    "description": "Extension service health status - degraded"
+  },
+  "extensionHealthOffline": "Offline",
+  "@extensionHealthOffline": {
+    "description": "Extension service health status - offline"
+  },
+  "extensionHealthNotConfigured": "Not configured",
+  "@extensionHealthNotConfigured": {
+    "description": "Extension service health status - not configured"
+  },
+  "extensionHealthUnknown": "Unknown",
+  "@extensionHealthUnknown": {
+    "description": "Extension service health status - unknown"
+  },
+  "extensionHealthRequired": "required",
+  "@extensionHealthRequired": {
+    "description": "Label for a required extension service health check"
+  },
+  "extensionSettingNotSet": "Not set",
+  "@extensionSettingNotSet": {
+    "description": "Value shown when an extension setting has no value"
+  },
+  "extensionActionFailed": "Action failed",
+  "@extensionActionFailed": {
+    "description": "Fallback error when an extension action fails without details"
+  },
+  "extensionEnterValue": "Enter value",
+  "@extensionEnterValue": {
+    "description": "Hint for editing an extension setting value"
+  },
+  "extensionHealthServiceOnline": "Service online",
+  "@extensionHealthServiceOnline": {
+    "description": "Tooltip for online extension service"
+  },
+  "extensionHealthServiceDegraded": "Service degraded",
+  "@extensionHealthServiceDegraded": {
+    "description": "Tooltip for degraded extension service"
+  },
+  "extensionHealthServiceOffline": "Service offline",
+  "@extensionHealthServiceOffline": {
+    "description": "Tooltip for offline extension service"
+  },
+  "extensionHealthServiceUnknown": "Service status unknown",
+  "@extensionHealthServiceUnknown": {
+    "description": "Tooltip for unknown extension service health"
+  },
+  "audioAnalysisStereo": "Stereo",
+  "@audioAnalysisStereo": {
+    "description": "Audio channel layout label - stereo"
+  },
+  "audioAnalysisMono": "Mono",
+  "@audioAnalysisMono": {
+    "description": "Audio channel layout label - mono"
+  },
+  "trackOpenInService": "Open in {serviceName}",
+  "@trackOpenInService": {
+    "description": "Button label to open a track in a named music service",
+    "placeholders": {
+      "serviceName": {
+        "type": "String"
+      }
+    }
+  },
+  "trackLyricsEmbeddedSource": "Embedded",
+  "@trackLyricsEmbeddedSource": {
+    "description": "Lyrics source label for embedded lyrics"
+  },
+  "unknownAlbum": "Unknown Album",
+  "@unknownAlbum": {
+    "description": "Fallback album name when metadata is missing"
+  },
+  "unknownArtist": "Unknown Artist",
+  "@unknownArtist": {
+    "description": "Fallback artist name when metadata is missing"
+  },
+  "permissionAudio": "Audio",
+  "@permissionAudio": {
+    "description": "Audio permission type label"
+  },
+  "permissionStorage": "Storage",
+  "@permissionStorage": {
+    "description": "Storage permission type label"
+  },
+  "permissionNotification": "Notification",
+  "@permissionNotification": {
+    "description": "Notification permission type label"
+  },
+  "errorInvalidFolderSelected": "Invalid folder selected",
+  "@errorInvalidFolderSelected": {
+    "description": "Error when the selected folder is invalid"
+  },
+  "errorCouldNotKeepFolderAccess": "Could not keep access to the selected folder",
+  "@errorCouldNotKeepFolderAccess": {
+    "description": "Error when persistent folder access cannot be saved"
+  },
+  "storeAnyVersion": "Any",
+  "@storeAnyVersion": {
+    "description": "Store detail value when any app version is accepted"
+  },
+  "storeCategoryMetadata": "Metadata",
+  "@storeCategoryMetadata": {
+    "description": "Store extension category - metadata"
+  },
+  "storeCategoryDownload": "Download",
+  "@storeCategoryDownload": {
+    "description": "Store extension category - download"
+  },
+  "storeCategoryUtility": "Utility",
+  "@storeCategoryUtility": {
+    "description": "Store extension category - utility"
+  },
+  "storeCategoryLyrics": "Lyrics",
+  "@storeCategoryLyrics": {
+    "description": "Store extension category - lyrics"
+  },
+  "storeCategoryIntegration": "Integration",
+  "@storeCategoryIntegration": {
+    "description": "Store extension category - integration"
+  },
+  "artistReleases": "Releases",
+  "@artistReleases": {
+    "description": "Section header for all artist releases"
+  },
+  "editMetadataSelectNone": "None",
+  "@editMetadataSelectNone": {
+    "description": "Button to clear selected fields for auto-fill"
+  },
+  "queueRetryAllFailed": "Retry {count} failed",
+  "@queueRetryAllFailed": {
+    "description": "Button to retry every failed download in the queue",
+    "placeholders": {
+      "count": {
+        "type": "int"
+      }
+    }
+  },
+  "settingsSaveDownloadHistory": "Save download history",
+  "@settingsSaveDownloadHistory": {
+    "description": "Settings switch title for storing completed downloads in history"
+  },
+  "settingsSaveDownloadHistorySubtitle": "Keep completed downloads in history and library views",
+  "@settingsSaveDownloadHistorySubtitle": {
+    "description": "Settings switch subtitle for storing completed downloads in history"
+  },
+  "dialogDisableHistoryTitle": "Turn off download history?",
+  "@dialogDisableHistoryTitle": {
+    "description": "Confirmation dialog title shown before disabling download history"
+  },
+  "dialogDisableHistoryMessage": "Existing history will be cleared. Downloaded files will not be deleted.",
+  "@dialogDisableHistoryMessage": {
+    "description": "Confirmation dialog message shown before disabling download history"
+  },
+  "dialogDisableAndClear": "Turn off and clear",
+  "@dialogDisableAndClear": {
+    "description": "Confirmation action to disable download history and clear existing entries"
+  },
+  "openInOtherServices": "Open in Other Services",
+  "@openInOtherServices": {
+    "description": "Title and tooltip for finding the current collection in other services"
+  },
+  "shareSheetNoExtensions": "No other compatible services",
+  "@shareSheetNoExtensions": {
+    "description": "Empty state when no extensions can be searched for cross-service links"
+  },
+  "shareSheetNotFound": "Not found",
+  "@shareSheetNotFound": {
+    "description": "Cross-service share sheet row subtitle when a service has no match"
+  },
+  "shareSheetCopyLink": "Copy Link",
+  "@shareSheetCopyLink": {
+    "description": "Tooltip for copying a cross-service link"
+  },
+  "shareSheetLinkCopied": "{service} link copied",
+  "@shareSheetLinkCopied": {
+    "description": "Snackbar after copying a cross-service link",
+    "placeholders": {
+      "service": {}
+    }
   }
 }

lib/l10n/arb/app_es.arb

@@ -142,9 +142,9 @@
       }
     }
   },
-  "optionsSwitchBack": "Tap Deezer or Spotify to switch back from extension",
+  "optionsSwitchBack": "Choose the default search provider to switch back from an extension",
   "@optionsSwitchBack": {
-    "description": "Hint to switch back to built-in providers"
+    "description": "Hint to switch back from extension search"
   },
   "optionsAutoFallback": "Auto Fallback",
   "@optionsAutoFallback": {
@@ -156,15 +156,15 @@
   },
   "optionsUseExtensionProviders": "Use Extension Providers",
   "@optionsUseExtensionProviders": {
-    "description": "Enable extension download providers"
+    "description": "Legacy setting label for extension download providers"
   },
-  "optionsUseExtensionProvidersOn": "Extensions will be tried first",
+  "optionsUseExtensionProvidersOn": "Extension providers are enabled",
   "@optionsUseExtensionProvidersOn": {
     "description": "Status when extension providers enabled"
   },
-  "optionsUseExtensionProvidersOff": "Using built-in providers only",
+  "optionsUseExtensionProvidersOff": "Extension providers are required",
   "@optionsUseExtensionProvidersOff": {
-    "description": "Status when extension providers disabled"
+    "description": "Legacy status when extension providers would be disabled"
   },
   "optionsEmbedLyrics": "Embed Lyrics",
   "@optionsEmbedLyrics": {
@@ -182,27 +182,6 @@
   "@optionsMaxQualityCoverSubtitle": {
     "description": "Subtitle for max quality cover"
   },
-  "optionsConcurrentDownloads": "Concurrent Downloads",
-  "@optionsConcurrentDownloads": {
-    "description": "Number of parallel downloads"
-  },
-  "optionsConcurrentSequential": "Sequential (1 at a time)",
-  "@optionsConcurrentSequential": {
-    "description": "Download one at a time"
-  },
-  "optionsConcurrentParallel": "{count} parallel downloads",
-  "@optionsConcurrentParallel": {
-    "description": "Multiple parallel downloads",
-    "placeholders": {
-      "count": {
-        "type": "int"
-      }
-    }
-  },
-  "optionsConcurrentWarning": "Parallel downloads may trigger rate limiting",
-  "@optionsConcurrentWarning": {
-    "description": "Warning about rate limits"
-  },
   "optionsExtensionStore": "Extension Store",
   "@optionsExtensionStore": {
     "description": "Show/hide store tab"
@@ -390,15 +369,15 @@
   "@aboutVersion": {
     "description": "Version info label"
   },
-  "aboutBinimumDesc": "The creator of QQDL & HiFi API. Without this API, Tidal downloads wouldn't exist!",
+  "aboutBinimumDesc": "The creator of QQDL & HiFi API. This project helped shape lossless download support.",
   "@aboutBinimumDesc": {
     "description": "Credit description for binimum"
   },
-  "aboutSachinsenalDesc": "The original HiFi project creator. The foundation of Tidal integration!",
+  "aboutSachinsenalDesc": "The original HiFi project creator. A foundation for lossless-source integration.",
   "@aboutSachinsenalDesc": {
     "description": "Credit description for sachinsenal0x64"
   },
-  "aboutAppDescription": "Download Spotify tracks in lossless quality from Tidal and Qobuz.",
+  "aboutAppDescription": "Search music metadata, manage extensions, and organize your library.",
   "@aboutAppDescription": {
     "description": "App description in header card"
   },
@@ -999,9 +978,9 @@
   "@providerPriorityInfo": {
     "description": "Info tip about fallback behavior"
   },
-  "providerBuiltIn": "Built-in",
+  "providerBuiltIn": "Legacy",
   "@providerBuiltIn": {
-    "description": "Label for built-in providers (Tidal/Qobuz)"
+    "description": "Legacy label retained for old generated localization compatibility"
   },
   "providerExtension": "Extension",
   "@providerExtension": {
@@ -1394,11 +1373,11 @@
   "@storeClearFilters": {
     "description": "Button to clear all filters"
   },
-  "extensionDefaultProvider": "Default (Deezer/Spotify)",
+  "extensionDefaultProvider": "Default Search",
   "@extensionDefaultProvider": {
     "description": "Default search provider option"
   },
-  "extensionDefaultProviderSubtitle": "Use built-in search",
+  "extensionDefaultProviderSubtitle": "Use the default metadata search",
   "@extensionDefaultProviderSubtitle": {
     "description": "Subtitle for default provider"
   },
@@ -2071,43 +2050,43 @@
   },
   "downloadLossy320": "Lossy 320kbps",
   "@downloadLossy320": {
-    "description": "Quality option label for Tidal lossy 320kbps"
+    "description": "Quality option label for lossy 320kbps"
   },
   "downloadLossyFormat": "Lossy Format",
   "@downloadLossyFormat": {
-    "description": "Setting title to pick output format for Tidal lossy downloads"
+    "description": "Setting title to pick output format for lossy downloads"
   },
   "downloadLossy320Format": "Lossy 320kbps Format",
   "@downloadLossy320Format": {
-    "description": "Title of the Tidal lossy format picker bottom sheet"
+    "description": "Title of the lossy format picker bottom sheet"
   },
-  "downloadLossy320FormatDesc": "Choose the output format for Tidal 320kbps lossy downloads. The original AAC stream will be converted to your selected format.",
+  "downloadLossy320FormatDesc": "Choose the output format for 320kbps lossy downloads. The original stream will be converted to your selected format when needed.",
   "@downloadLossy320FormatDesc": {
-    "description": "Description in the Tidal lossy format picker"
+    "description": "Description in the lossy format picker"
   },
   "downloadLossyMp3": "MP3 320kbps",
   "@downloadLossyMp3": {
-    "description": "Tidal lossy format option - MP3 320kbps"
+    "description": "lossy format option - MP3 320kbps"
   },
   "downloadLossyMp3Subtitle": "Best compatibility, ~10MB per track",
   "@downloadLossyMp3Subtitle": {
-    "description": "Subtitle for MP3 320kbps Tidal lossy option"
+    "description": "Subtitle for MP3 320kbps lossy option"
   },
   "downloadLossyOpus256": "Opus 256kbps",
   "@downloadLossyOpus256": {
-    "description": "Tidal lossy format option - Opus 256kbps"
+    "description": "lossy format option - Opus 256kbps"
   },
   "downloadLossyOpus256Subtitle": "Best quality Opus, ~8MB per track",
   "@downloadLossyOpus256Subtitle": {
-    "description": "Subtitle for Opus 256kbps Tidal lossy option"
+    "description": "Subtitle for Opus 256kbps lossy option"
   },
   "downloadLossyOpus128": "Opus 128kbps",
   "@downloadLossyOpus128": {
-    "description": "Tidal lossy format option - Opus 128kbps"
+    "description": "lossy format option - Opus 128kbps"
   },
   "downloadLossyOpus128Subtitle": "Smallest size, ~4MB per track",
   "@downloadLossyOpus128Subtitle": {
-    "description": "Subtitle for Opus 128kbps Tidal lossy option"
+    "description": "Subtitle for Opus 128kbps lossy option"
   },
   "downloadUseAlbumArtistForFolders": "Use Album Artist for folders",
   "@downloadUseAlbumArtistForFolders": {
@@ -2697,7 +2676,7 @@
   "@tutorialWelcomeTip1": {
     "description": "Tutorial welcome tip 1"
   },
-  "tutorialWelcomeTip2": "Get FLAC quality audio from Tidal, Qobuz, or Deezer",
+  "tutorialWelcomeTip2": "Get FLAC quality audio from installed download extensions",
   "@tutorialWelcomeTip2": {
     "description": "Tutorial welcome tip 2"
   },
@@ -3600,7 +3579,7 @@
   "@lyricsProvidersDescription": {
     "description": "Description on the lyrics provider priority page"
   },
-  "lyricsProvidersInfoText": "Extension lyrics providers always run before built-in providers. At least one provider must remain enabled.",
+  "lyricsProvidersInfoText": "Extension lyrics providers run before built-in lyrics providers. At least one provider must remain enabled.",
   "@lyricsProvidersInfoText": {
     "description": "Info tip on lyrics provider priority page"
   },
@@ -3838,13 +3817,13 @@
   "@downloadNetworkCompatibilityModeDisabled": {
     "description": "Subtitle when network compatibility mode is off"
   },
-  "downloadSelectServiceToEnable": "Select Tidal or Qobuz to enable this option",
+  "downloadSelectServiceToEnable": "Select a provider with quality options to enable this option",
   "@downloadSelectServiceToEnable": {
     "description": "Subtitle when quality picker is disabled due to extension service"
   },
-  "downloadSelectTidalQobuz": "Select Tidal or Qobuz to choose audio quality",
+  "downloadSelectTidalQobuz": "Select a provider with quality options to choose audio quality",
   "@downloadSelectTidalQobuz": {
-    "description": "Info shown when a non-built-in service is selected"
+    "description": "Legacy info shown when a provider does not expose quality options"
   },
   "downloadEmbedLyricsDisabled": "Enable metadata embedding first",
   "@downloadEmbedLyricsDisabled": {
@@ -4196,9 +4175,17 @@
   "@audioAnalysisSamples": {
     "description": "Total samples metric label"
   },
+  "audioAnalysisRescan": "Re-analyze",
+  "@audioAnalysisRescan": {
+    "description": "Tooltip/label for the button that re-runs the audio analysis, discarding cached results"
+  },
+  "audioAnalysisRescanning": "Re-analyzing audio...", 
+  "@audioAnalysisRescanning": {
+    "description": "Loading text while audio is being re-analyzed after an explicit refresh"
+  },
   "extensionsSearchWith": "Search with {providerName}",
   "@extensionsSearchWith": {
-    "description": "Extensions page - subtitle for built-in search provider option",
+    "description": "Extensions page - subtitle for default metadata search provider option",
     "placeholders": {
       "providerName": {
         "type": "String"

lib/l10n/arb/app_pt.arb

@@ -142,9 +142,9 @@
       }
     }
   },
-  "optionsSwitchBack": "Tap Deezer or Spotify to switch back from extension",
+  "optionsSwitchBack": "Choose the default search provider to switch back from an extension",
   "@optionsSwitchBack": {
-    "description": "Hint to switch back to built-in providers"
+    "description": "Hint to switch back from extension search"
   },
   "optionsAutoFallback": "Auto Fallback",
   "@optionsAutoFallback": {
@@ -156,15 +156,15 @@
   },
   "optionsUseExtensionProviders": "Use Extension Providers",
   "@optionsUseExtensionProviders": {
-    "description": "Enable extension download providers"
+    "description": "Legacy setting label for extension download providers"
   },
-  "optionsUseExtensionProvidersOn": "Extensions will be tried first",
+  "optionsUseExtensionProvidersOn": "Extension providers are enabled",
   "@optionsUseExtensionProvidersOn": {
     "description": "Status when extension providers enabled"
   },
-  "optionsUseExtensionProvidersOff": "Using built-in providers only",
+  "optionsUseExtensionProvidersOff": "Extension providers are required",
   "@optionsUseExtensionProvidersOff": {
-    "description": "Status when extension providers disabled"
+    "description": "Legacy status when extension providers would be disabled"
   },
   "optionsEmbedLyrics": "Embed Lyrics",
   "@optionsEmbedLyrics": {
@@ -182,27 +182,6 @@
   "@optionsMaxQualityCoverSubtitle": {
     "description": "Subtitle for max quality cover"
   },
-  "optionsConcurrentDownloads": "Concurrent Downloads",
-  "@optionsConcurrentDownloads": {
-    "description": "Number of parallel downloads"
-  },
-  "optionsConcurrentSequential": "Sequential (1 at a time)",
-  "@optionsConcurrentSequential": {
-    "description": "Download one at a time"
-  },
-  "optionsConcurrentParallel": "{count} parallel downloads",
-  "@optionsConcurrentParallel": {
-    "description": "Multiple parallel downloads",
-    "placeholders": {
-      "count": {
-        "type": "int"
-      }
-    }
-  },
-  "optionsConcurrentWarning": "Parallel downloads may trigger rate limiting",
-  "@optionsConcurrentWarning": {
-    "description": "Warning about rate limits"
-  },
   "optionsExtensionStore": "Extension Store",
   "@optionsExtensionStore": {
     "description": "Show/hide store tab"
@@ -390,15 +369,15 @@
   "@aboutVersion": {
     "description": "Version info label"
   },
-  "aboutBinimumDesc": "The creator of QQDL & HiFi API. Without this API, Tidal downloads wouldn't exist!",
+  "aboutBinimumDesc": "The creator of QQDL & HiFi API. This project helped shape lossless download support.",
   "@aboutBinimumDesc": {
     "description": "Credit description for binimum"
   },
-  "aboutSachinsenalDesc": "The original HiFi project creator. The foundation of Tidal integration!",
+  "aboutSachinsenalDesc": "The original HiFi project creator. A foundation for lossless-source integration.",
   "@aboutSachinsenalDesc": {
     "description": "Credit description for sachinsenal0x64"
   },
-  "aboutAppDescription": "Download Spotify tracks in lossless quality from Tidal and Qobuz.",
+  "aboutAppDescription": "Search music metadata, manage extensions, and organize your library.",
   "@aboutAppDescription": {
     "description": "App description in header card"
   },
@@ -999,9 +978,9 @@
   "@providerPriorityInfo": {
     "description": "Info tip about fallback behavior"
   },
-  "providerBuiltIn": "Built-in",
+  "providerBuiltIn": "Legacy",
   "@providerBuiltIn": {
-    "description": "Label for built-in providers (Tidal/Qobuz)"
+    "description": "Legacy label retained for old generated localization compatibility"
   },
   "providerExtension": "Extension",
   "@providerExtension": {
@@ -1394,11 +1373,11 @@
   "@storeClearFilters": {
     "description": "Button to clear all filters"
   },
-  "extensionDefaultProvider": "Default (Deezer/Spotify)",
+  "extensionDefaultProvider": "Default Search",
   "@extensionDefaultProvider": {
     "description": "Default search provider option"
   },
-  "extensionDefaultProviderSubtitle": "Use built-in search",
+  "extensionDefaultProviderSubtitle": "Use the default metadata search",
   "@extensionDefaultProviderSubtitle": {
     "description": "Subtitle for default provider"
   },
@@ -2071,43 +2050,43 @@
   },
   "downloadLossy320": "Lossy 320kbps",
   "@downloadLossy320": {
-    "description": "Quality option label for Tidal lossy 320kbps"
+    "description": "Quality option label for lossy 320kbps"
   },
   "downloadLossyFormat": "Lossy Format",
   "@downloadLossyFormat": {
-    "description": "Setting title to pick output format for Tidal lossy downloads"
+    "description": "Setting title to pick output format for lossy downloads"
   },
   "downloadLossy320Format": "Lossy 320kbps Format",
   "@downloadLossy320Format": {
-    "description": "Title of the Tidal lossy format picker bottom sheet"
+    "description": "Title of the lossy format picker bottom sheet"
   },
-  "downloadLossy320FormatDesc": "Choose the output format for Tidal 320kbps lossy downloads. The original AAC stream will be converted to your selected format.",
+  "downloadLossy320FormatDesc": "Choose the output format for 320kbps lossy downloads. The original stream will be converted to your selected format when needed.",
   "@downloadLossy320FormatDesc": {
-    "description": "Description in the Tidal lossy format picker"
+    "description": "Description in the lossy format picker"
   },
   "downloadLossyMp3": "MP3 320kbps",
   "@downloadLossyMp3": {
-    "description": "Tidal lossy format option - MP3 320kbps"
+    "description": "lossy format option - MP3 320kbps"
   },
   "downloadLossyMp3Subtitle": "Best compatibility, ~10MB per track",
   "@downloadLossyMp3Subtitle": {
-    "description": "Subtitle for MP3 320kbps Tidal lossy option"
+    "description": "Subtitle for MP3 320kbps lossy option"
   },
   "downloadLossyOpus256": "Opus 256kbps",
   "@downloadLossyOpus256": {
-    "description": "Tidal lossy format option - Opus 256kbps"
+    "description": "lossy format option - Opus 256kbps"
   },
   "downloadLossyOpus256Subtitle": "Best quality Opus, ~8MB per track",
   "@downloadLossyOpus256Subtitle": {
-    "description": "Subtitle for Opus 256kbps Tidal lossy option"
+    "description": "Subtitle for Opus 256kbps lossy option"
   },
   "downloadLossyOpus128": "Opus 128kbps",
   "@downloadLossyOpus128": {
-    "description": "Tidal lossy format option - Opus 128kbps"
+    "description": "lossy format option - Opus 128kbps"
   },
   "downloadLossyOpus128Subtitle": "Smallest size, ~4MB per track",
   "@downloadLossyOpus128Subtitle": {
-    "description": "Subtitle for Opus 128kbps Tidal lossy option"
+    "description": "Subtitle for Opus 128kbps lossy option"
   },
   "downloadUseAlbumArtistForFolders": "Use Album Artist for folders",
   "@downloadUseAlbumArtistForFolders": {
@@ -2697,7 +2676,7 @@
   "@tutorialWelcomeTip1": {
     "description": "Tutorial welcome tip 1"
   },
-  "tutorialWelcomeTip2": "Get FLAC quality audio from Tidal, Qobuz, or Deezer",
+  "tutorialWelcomeTip2": "Get FLAC quality audio from installed download extensions",
   "@tutorialWelcomeTip2": {
     "description": "Tutorial welcome tip 2"
   },
@@ -3600,7 +3579,7 @@
   "@lyricsProvidersDescription": {
     "description": "Description on the lyrics provider priority page"
   },
-  "lyricsProvidersInfoText": "Extension lyrics providers always run before built-in providers. At least one provider must remain enabled.",
+  "lyricsProvidersInfoText": "Extension lyrics providers run before built-in lyrics providers. At least one provider must remain enabled.",
   "@lyricsProvidersInfoText": {
     "description": "Info tip on lyrics provider priority page"
   },
@@ -3838,13 +3817,13 @@
   "@downloadNetworkCompatibilityModeDisabled": {
     "description": "Subtitle when network compatibility mode is off"
   },
-  "downloadSelectServiceToEnable": "Select Tidal or Qobuz to enable this option",
+  "downloadSelectServiceToEnable": "Select a provider with quality options to enable this option",
   "@downloadSelectServiceToEnable": {
     "description": "Subtitle when quality picker is disabled due to extension service"
   },
-  "downloadSelectTidalQobuz": "Select Tidal or Qobuz to choose audio quality",
+  "downloadSelectTidalQobuz": "Select a provider with quality options to choose audio quality",
   "@downloadSelectTidalQobuz": {
-    "description": "Info shown when a non-built-in service is selected"
+    "description": "Legacy info shown when a provider does not expose quality options"
   },
   "downloadEmbedLyricsDisabled": "Enable metadata embedding first",
   "@downloadEmbedLyricsDisabled": {
@@ -4196,9 +4175,17 @@
   "@audioAnalysisSamples": {
     "description": "Total samples metric label"
   },
+  "audioAnalysisRescan": "Re-analyze",
+  "@audioAnalysisRescan": {
+    "description": "Tooltip/label for the button that re-runs the audio analysis, discarding cached results"
+  },
+  "audioAnalysisRescanning": "Re-analyzing audio...", 
+  "@audioAnalysisRescanning": {
+    "description": "Loading text while audio is being re-analyzed after an explicit refresh"
+  },
   "extensionsSearchWith": "Search with {providerName}",
   "@extensionsSearchWith": {
-    "description": "Extensions page - subtitle for built-in search provider option",
+    "description": "Extensions page - subtitle for default metadata search provider option",
     "placeholders": {
       "providerName": {
         "type": "String"

lib/l10n/arb/app_zh.arb

@@ -142,9 +142,9 @@
       }
     }
   },
-  "optionsSwitchBack": "Tap Deezer or Spotify to switch back from extension",
+  "optionsSwitchBack": "Choose the default search provider to switch back from an extension",
   "@optionsSwitchBack": {
-    "description": "Hint to switch back to built-in providers"
+    "description": "Hint to switch back from extension search"
   },
   "optionsAutoFallback": "Auto Fallback",
   "@optionsAutoFallback": {
@@ -156,15 +156,15 @@
   },
   "optionsUseExtensionProviders": "Use Extension Providers",
   "@optionsUseExtensionProviders": {
-    "description": "Enable extension download providers"
+    "description": "Legacy setting label for extension download providers"
   },
-  "optionsUseExtensionProvidersOn": "Extensions will be tried first",
+  "optionsUseExtensionProvidersOn": "Extension providers are enabled",
   "@optionsUseExtensionProvidersOn": {
     "description": "Status when extension providers enabled"
   },
-  "optionsUseExtensionProvidersOff": "Using built-in providers only",
+  "optionsUseExtensionProvidersOff": "Extension providers are required",
   "@optionsUseExtensionProvidersOff": {
-    "description": "Status when extension providers disabled"
+    "description": "Legacy status when extension providers would be disabled"
   },
   "optionsEmbedLyrics": "Embed Lyrics",
   "@optionsEmbedLyrics": {
@@ -182,27 +182,6 @@
   "@optionsMaxQualityCoverSubtitle": {
     "description": "Subtitle for max quality cover"
   },
-  "optionsConcurrentDownloads": "Concurrent Downloads",
-  "@optionsConcurrentDownloads": {
-    "description": "Number of parallel downloads"
-  },
-  "optionsConcurrentSequential": "Sequential (1 at a time)",
-  "@optionsConcurrentSequential": {
-    "description": "Download one at a time"
-  },
-  "optionsConcurrentParallel": "{count} parallel downloads",
-  "@optionsConcurrentParallel": {
-    "description": "Multiple parallel downloads",
-    "placeholders": {
-      "count": {
-        "type": "int"
-      }
-    }
-  },
-  "optionsConcurrentWarning": "Parallel downloads may trigger rate limiting",
-  "@optionsConcurrentWarning": {
-    "description": "Warning about rate limits"
-  },
   "optionsExtensionStore": "Extension Store",
   "@optionsExtensionStore": {
     "description": "Show/hide store tab"
@@ -390,15 +369,15 @@
   "@aboutVersion": {
     "description": "Version info label"
   },
-  "aboutBinimumDesc": "The creator of QQDL & HiFi API. Without this API, Tidal downloads wouldn't exist!",
+  "aboutBinimumDesc": "The creator of QQDL & HiFi API. This project helped shape lossless download support.",
   "@aboutBinimumDesc": {
     "description": "Credit description for binimum"
   },
-  "aboutSachinsenalDesc": "The original HiFi project creator. The foundation of Tidal integration!",
+  "aboutSachinsenalDesc": "The original HiFi project creator. A foundation for lossless-source integration.",
   "@aboutSachinsenalDesc": {
     "description": "Credit description for sachinsenal0x64"
   },
-  "aboutAppDescription": "Download Spotify tracks in lossless quality from Tidal and Qobuz.",
+  "aboutAppDescription": "Search music metadata, manage extensions, and organize your library.",
   "@aboutAppDescription": {
     "description": "App description in header card"
   },
@@ -999,9 +978,9 @@
   "@providerPriorityInfo": {
     "description": "Info tip about fallback behavior"
   },
-  "providerBuiltIn": "Built-in",
+  "providerBuiltIn": "Legacy",
   "@providerBuiltIn": {
-    "description": "Label for built-in providers (Tidal/Qobuz)"
+    "description": "Legacy label retained for old generated localization compatibility"
   },
   "providerExtension": "Extension",
   "@providerExtension": {
@@ -1394,11 +1373,11 @@
   "@storeClearFilters": {
     "description": "Button to clear all filters"
   },
-  "extensionDefaultProvider": "Default (Deezer/Spotify)",
+  "extensionDefaultProvider": "Default Search",
   "@extensionDefaultProvider": {
     "description": "Default search provider option"
   },
-  "extensionDefaultProviderSubtitle": "Use built-in search",
+  "extensionDefaultProviderSubtitle": "Use the default metadata search",
   "@extensionDefaultProviderSubtitle": {
     "description": "Subtitle for default provider"
   },
@@ -2071,43 +2050,43 @@
   },
   "downloadLossy320": "Lossy 320kbps",
   "@downloadLossy320": {
-    "description": "Quality option label for Tidal lossy 320kbps"
+    "description": "Quality option label for lossy 320kbps"
   },
   "downloadLossyFormat": "Lossy Format",
   "@downloadLossyFormat": {
-    "description": "Setting title to pick output format for Tidal lossy downloads"
+    "description": "Setting title to pick output format for lossy downloads"
   },
   "downloadLossy320Format": "Lossy 320kbps Format",
   "@downloadLossy320Format": {
-    "description": "Title of the Tidal lossy format picker bottom sheet"
+    "description": "Title of the lossy format picker bottom sheet"
   },
-  "downloadLossy320FormatDesc": "Choose the output format for Tidal 320kbps lossy downloads. The original AAC stream will be converted to your selected format.",
+  "downloadLossy320FormatDesc": "Choose the output format for 320kbps lossy downloads. The original stream will be converted to your selected format when needed.",
   "@downloadLossy320FormatDesc": {
-    "description": "Description in the Tidal lossy format picker"
+    "description": "Description in the lossy format picker"
   },
   "downloadLossyMp3": "MP3 320kbps",
   "@downloadLossyMp3": {
-    "description": "Tidal lossy format option - MP3 320kbps"
+    "description": "lossy format option - MP3 320kbps"
   },
   "downloadLossyMp3Subtitle": "Best compatibility, ~10MB per track",
   "@downloadLossyMp3Subtitle": {
-    "description": "Subtitle for MP3 320kbps Tidal lossy option"
+    "description": "Subtitle for MP3 320kbps lossy option"
   },
   "downloadLossyOpus256": "Opus 256kbps",
   "@downloadLossyOpus256": {
-    "description": "Tidal lossy format option - Opus 256kbps"
+    "description": "lossy format option - Opus 256kbps"
   },
   "downloadLossyOpus256Subtitle": "Best quality Opus, ~8MB per track",
   "@downloadLossyOpus256Subtitle": {
-    "description": "Subtitle for Opus 256kbps Tidal lossy option"
+    "description": "Subtitle for Opus 256kbps lossy option"
   },
   "downloadLossyOpus128": "Opus 128kbps",
   "@downloadLossyOpus128": {
-    "description": "Tidal lossy format option - Opus 128kbps"
+    "description": "lossy format option - Opus 128kbps"
   },
   "downloadLossyOpus128Subtitle": "Smallest size, ~4MB per track",
   "@downloadLossyOpus128Subtitle": {
-    "description": "Subtitle for Opus 128kbps Tidal lossy option"
+    "description": "Subtitle for Opus 128kbps lossy option"
   },
   "downloadUseAlbumArtistForFolders": "Use Album Artist for folders",
   "@downloadUseAlbumArtistForFolders": {
@@ -2697,7 +2676,7 @@
   "@tutorialWelcomeTip1": {
     "description": "Tutorial welcome tip 1"
   },
-  "tutorialWelcomeTip2": "Get FLAC quality audio from Tidal, Qobuz, or Deezer",
+  "tutorialWelcomeTip2": "Get FLAC quality audio from installed download extensions",
   "@tutorialWelcomeTip2": {
     "description": "Tutorial welcome tip 2"
   },
@@ -3600,7 +3579,7 @@
   "@lyricsProvidersDescription": {
     "description": "Description on the lyrics provider priority page"
   },
-  "lyricsProvidersInfoText": "Extension lyrics providers always run before built-in providers. At least one provider must remain enabled.",
+  "lyricsProvidersInfoText": "Extension lyrics providers run before built-in lyrics providers. At least one provider must remain enabled.",
   "@lyricsProvidersInfoText": {
     "description": "Info tip on lyrics provider priority page"
   },
@@ -3838,13 +3817,13 @@
   "@downloadNetworkCompatibilityModeDisabled": {
     "description": "Subtitle when network compatibility mode is off"
   },
-  "downloadSelectServiceToEnable": "Select Tidal or Qobuz to enable this option",
+  "downloadSelectServiceToEnable": "Select a provider with quality options to enable this option",
   "@downloadSelectServiceToEnable": {
     "description": "Subtitle when quality picker is disabled due to extension service"
   },
-  "downloadSelectTidalQobuz": "Select Tidal or Qobuz to choose audio quality",
+  "downloadSelectTidalQobuz": "Select a provider with quality options to choose audio quality",
   "@downloadSelectTidalQobuz": {
-    "description": "Info shown when a non-built-in service is selected"
+    "description": "Legacy info shown when a provider does not expose quality options"
   },
   "downloadEmbedLyricsDisabled": "Enable metadata embedding first",
   "@downloadEmbedLyricsDisabled": {
@@ -4196,9 +4175,17 @@
   "@audioAnalysisSamples": {
     "description": "Total samples metric label"
   },
+  "audioAnalysisRescan": "Re-analyze",
+  "@audioAnalysisRescan": {
+    "description": "Tooltip/label for the button that re-runs the audio analysis, discarding cached results"
+  },
+  "audioAnalysisRescanning": "Re-analyzing audio...", 
+  "@audioAnalysisRescanning": {
+    "description": "Loading text while audio is being re-analyzed after an explicit refresh"
+  },
   "extensionsSearchWith": "Search with {providerName}",
   "@extensionsSearchWith": {
-    "description": "Extensions page - subtitle for built-in search provider option",
+    "description": "Extensions page - subtitle for default metadata search provider option",
     "placeholders": {
       "providerName": {
         "type": "String"

lib/l10n/supported_locales.dart

@@ -14,23 +14,27 @@ const int translationThreshold = 70;
 /// Only these languages will be available in the app.
 const List<Locale> filteredSupportedLocales = <Locale>[
   Locale('en'),
-  Locale('ru'),
+  Locale('fr'),
+  Locale('de'),
   Locale('es', 'ES'),
-  Locale('id'),
-  Locale('pt', 'PT'),
-  Locale('ja'),
-  Locale('tr'),
   Locale('uk'),
+  Locale('ru'),
+  Locale('tr'),
+  Locale('id'),
+  Locale('ja'),
+  Locale('pt', 'PT'),
 ];
 
 /// Set of locale codes for quick lookup.
 const Set<String> filteredLocaleCodes = <String>{
   'en',
-  'ru',
+  'fr',
+  'de',
   'es_ES',
-  'id',
-  'pt_PT',
-  'ja',
-  'tr',
   'uk',
+  'ru',
+  'tr',
+  'id',
+  'ja',
+  'pt_PT',
 };