Introduce AppRemoteConfigService which fetches a platform/version/locale-aware JSON payload from api.zarz.moe/v1/spotiflac-mobile/config and caches it in SharedPreferences. main_shell shows a one-shot announcement dialog (respecting dismissible, CTA, time window and version gates) when no update prompt is pending; dismissed IDs are persisted so each announcement surfaces only once.
Tweaks bundled in: the service health dot loses its blur halo in favour of solid Material 3 tones, and AppInfo gains the remote config endpoint constant. The share listener and SAF migration hook stay synchronous inside the post-frame callback so share-intent URLs never race the network-bound checks.
New unit tests cover the announcement CTA/active-window rules.
The SAF and local post-download branches used to rush an ffmpeg 'M4A to FLAC' remux whenever the output extension was .flac, which silently upscaled AAC or EAC3 streams into a lossless container. Each branch now mirrors the native worker by probing the primary audio codec before converting: lossless sources (and true FLAC-in-MP4 files) stay in their native container with the right extension, while genuine ALAC/WAV payloads still get remuxed.
Add an outputExt field to DownloadRequestPayload so the Go backend always knows the user-requested container, and use it together with _shouldRequestContainerConversion to pick the right behaviour for shouldPreserveNativeM4a and the Kotlin finalizer. Decryption descriptors no longer force M4A preservation on their own; the codec probe already makes that call correctly.
Bump the history schema on both the Kotlin finalizer and the Dart database to v9, adding bitrate (kbps) and format (codec label) columns, and let the download flow fill them from backend/probe metadata so lossy downloads keep a 'AAC 256kbps' label instead of falling back to the stored placeholder. Library filtering and the track metadata screen now read format/bitrate directly from those columns, which also fixes mis-tagged quality badges after re-downloading a track at a different format.
Additional fixes bundled in: EditFileMetadata now routes ReplayGain writes through the M4A path whenever the file starts with ftyp (fixing .flac files that actually hold MP4 containers); GetM4AQuality falls back to the first trak/mdia/mdhd duration when mvhd is zero so EAC3 streams no longer report 0s; and both Kotlin and Dart reject bitrate values below 16 kbps to prevent probe noise from surfacing as '0 kbps' labels. New unit tests cover the EAC3 mdhd fallback and the mis-named M4A replaygain path.
GetM4AQuality now recognizes fLaC, alac, ec-3, ac-3, and ac-4 sample entries and parses the MP4 FLACSpecificBox so library entries carry the real codec rather than the container extension. The AudioQuality struct exposes Codec and Bitrate fields (with an estimator for compressed streams), and ReadFileMetadata publishes format + audio_codec so Flutter and Kotlin can make format decisions based on the actual stream.
Downstream: library_scan labels M4A-family items as flac/alac/eac3/ac3/ac4/m4a, zeroes the bitrate for lossless formats, and the filter UI + quality badges use the codec-derived format instead of only the file extension. Scans and SAF importers also accept .mp4 and .aac file extensions. New unit tests cover codec name mapping and MP4 FLACSpecificBox decoding.
The audio analysis card used to read from a persistent cache but offered no way to refresh the result when the underlying file had been re-downloaded at a different quality (for example, re-downloading a track as FLAC after capturing it as AAC). Add an explicit rescan control that clears the cached JSON + spectrogram, reruns the FFmpeg probe and analysis pipeline, and swaps in the fresh data while keeping the loading copy distinct from first-run analysis. A retry button is also exposed in the error card so transient failures do not require navigating away.
All audio_analysis strings now have a Re-analyze / Re-analyzing pair in the ARB catalog so every locale can translate them independently.
Add a pair of floating quick-scroll buttons on the library tab so long lists become easier to navigate. The buttons sit above the bottom navigation (or the selection toolbar in selection mode), fade in and out based on the active page's scroll metrics, and share their scroll-target keys per filter mode so switching filters does not carry over the previous page's scroll state.
Downloads from providers that stream FLAC inside an fMP4 container (e.g. Amazon Music) were being written to disk with a .flac extension while the payload still carried ISO-BMFF atoms. The container-conversion guard then saw codec=flac and skipped the remux, leaving native FLAC tag writers to fail with 'fLaC head incorrect'.
Force '-f flac' on the decryption command whenever the target extension is .flac so FFmpeg emits a real FLAC stream, and add an 'fLaC' magic-byte probe on both the Dart and Kotlin container-conversion guards so a FLAC-in-MP4 source is remuxed rather than silently passed through as a tag-writer hazard.
GetM4AQuality previously defaulted to 16-bit whenever the audio sample entry was not ALAC, which silently labeled lossy AAC downloads as CD quality in the library and in extension APIs. Only fill BitDepth when the atom is ALAC (including the ALACSpecificConfig refinement), and leave it as zero for AAC/mp4a, matching how the MP3 and Opus probes already report lossy sources. Tests cover both the ALAC and AAC branches.
The native-worker container conversion used to remux any .m4a download to .flac whenever the user requested a FLAC output, which silently upgraded lossy AAC streams to a FLAC container without adding any information. Guard the remux with an FFmpeg/FFprobe codec probe on both the Dart and Kotlin finalization paths so only genuinely lossless sources (ALAC, WavPack, PCM, etc.) are converted, and expose a requires_container_conversion capability so extensions can force conversion when they know the source is lossless.
When the native worker result advertises a requested non-FLAC output extension (for example '.m4a'), skip the m4a-to-flac container conversion in both the Dart and Kotlin finalizers so the native output container is preserved end-to-end.
- ffmpeg_service: propagate the top-level 'output_extension' hint into the download-result descriptor for both the map-backed and legacy paths; expose a normalized getter for consistent comparisons.
- download_queue_provider: short-circuit the native-worker container-conversion step when the descriptor's requested extension is not '.flac', with a debug log describing the skip.
- NativeDownloadFinalizer: mirror the guard on the Kotlin side so the finalizer does not force a container conversion that would clobber the requested native output.
Staged SAF outputs and library-scan partials now share a single naming pattern: '<name>.partial' regardless of the audio extension. The previous '<name>.partial.<ext>' form caused SAF / media-scanner to surface half-written files as valid audio.
- SafDownloadHandler: force 'application/octet-stream' MIME for staged docs and collapse buildStagedSafFileName to '<name>.partial'. Keep the legacy form behind buildLegacyStagedSafFileName and sweep both via deleteStaleStagedFiles so upgrades clean old residue.
- library_scan: add isLibraryStagingFile that skips both the new and legacy partial patterns during collectLibraryAudioFiles so residual staging files never show up in the library.
- library_scan_supplement_test: seed both legacy and new partial files and assert they are ignored by the scanner.
Use the 3-arg startForeground overload with FOREGROUND_SERVICE_TYPE_DATA_SYNC on API 29+ so the runtime FGS type matches the manifest declaration. Silences the ForegroundServiceTypeLoggerModule warning on targetSdk 36.
Zarz Eleutherius