diff --git a/src/core/AnonymizedFile.ts b/src/core/AnonymizedFile.ts
index 4de0861..01c4b19 100644
--- a/src/core/AnonymizedFile.ts
+++ b/src/core/AnonymizedFile.ts
@@ -271,7 +271,16 @@ export default class AnonymizedFile {
         } else if (isTextFile(this.anonymizedPath)) {
           res.contentType("text/plain");
         }
-        res.header("Accept-Ranges", "none");
+        // For text files we anonymize on the fly and the output length can
+        // differ from the upstream, so byte ranges aren't meaningful — keep
+        // Accept-Ranges: none. For binary files (images, video, archives)
+        // the transformer is a passthrough, so omitting the explicit "none"
+        // lets <video>/<audio> elements use the standard fallback to a full
+        // download instead of refusing to play (#538).
+        const isTextEntry = isTextFile(this.anonymizedPath) === true;
+        if (isTextEntry) {
+          res.header("Accept-Ranges", "none");
+        }
         anonymizer.once("transform", (data) => {
           if (!mime && data.isText) {
             res.contentType("text/plain");
diff --git a/src/streamer/route.ts b/src/streamer/route.ts
index 273d3cd..1266bde 100644
--- a/src/streamer/route.ts
+++ b/src/streamer/route.ts
@@ -66,7 +66,13 @@ router.post("/", async (req: express.Request, res: express.Response) => {
     } else if (isTextFile(filePath)) {
       res.contentType("text/plain");
     }
-    res.header("Accept-Ranges", "none");
+    // Only declare Accept-Ranges: none for text files — they get rewritten on
+    // the fly so byte ranges aren't meaningful. For binary entries the
+    // transformer is a passthrough; let <video>/<audio> fall back to a full
+    // download instead of refusing to play (#538).
+    if (isTextFile(filePath)) {
+      res.header("Accept-Ranges", "none");
+    }
     anonymizer.once("transform", (data) => {
       if (!mime && data.isText) {
         res.contentType("text/plain");