diff --git a/src/decrypt-worker/util/audioType.ts b/src/decrypt-worker/util/audioType.ts
index 71b1b58..bff53ee 100644
--- a/src/decrypt-worker/util/audioType.ts
+++ b/src/decrypt-worker/util/audioType.ts
@@ -24,3 +24,17 @@ export function isDataLooksLikeAudio(buffer: Uint8Array): boolean {
   detectResult.free();
   return ok;
 }
+
+const AudioMimeType: Record<string, string> = {
+  mp3: 'audio/mpeg',
+  flac: 'audio/flac',
+  m4a: 'audio/mp4',
+  ogg: 'audio/ogg',
+  wma: 'audio/x-ms-wma',
+  wav: 'audio/x-wav',
+  dff: 'audio/x-dff',
+};
+
+export function getMimeTypeFromExt(ext: string) {
+  return AudioMimeType[ext] || 'application/octet-stream';
+}
diff --git a/src/decrypt-worker/util/buffer.ts b/src/decrypt-worker/util/buffer.ts
index d7d95cf..b6617c5 100644
--- a/src/decrypt-worker/util/buffer.ts
+++ b/src/decrypt-worker/util/buffer.ts
@@ -1,7 +1,7 @@
 export const toArrayBuffer = async (src: Blob | ArrayBuffer | Uint8Array<ArrayBufferLike>) =>
   src instanceof Blob ? await src.arrayBuffer() : src;
-export const toBlob = (src: Blob | ArrayBuffer | Uint8Array<ArrayBufferLike>) =>
-  src instanceof Blob ? src : new Blob([src]);
+export const toBlob = (src: Blob | ArrayBuffer | Uint8Array<ArrayBufferLike>, mimeType?: string) =>
+  src instanceof Blob ? src : new Blob([src], { type: mimeType ?? 'application/octet-stream' });
 
 export function* chunkBuffer(buffer: Uint8Array, blockLen = 4096): Generator<[Uint8Array, number], void> {
   const len = buffer.byteLength;
diff --git a/src/decrypt-worker/worker/decrypt.ts b/src/decrypt-worker/worker/decrypt.ts
index 7c146c9..1b7ee96 100644
--- a/src/decrypt-worker/worker/decrypt.ts
+++ b/src/decrypt-worker/worker/decrypt.ts
@@ -6,7 +6,7 @@ import { DecipherFactory, DecipherInstance, Status } from '~/decrypt-worker/Deci
 import { UnsupportedSourceFile } from '~/decrypt-worker/util/DecryptError.ts';
 import { ready as umCryptoReady } from '@unlock-music/crypto';
 import { go } from '~/util/go.ts';
-import { detectAudioExtension } from '~/decrypt-worker/util/audioType.ts';
+import { getMimeTypeFromExt, detectAudioExtension } from '~/decrypt-worker/util/audioType.ts';
 
 class DecryptCommandHandler {
   private readonly label: string;
@@ -75,7 +75,7 @@ class DecryptCommandHandler {
       audioExt = 'm4a';
     }
 
-    return { decrypted: URL.createObjectURL(toBlob(result.data)), ext: audioExt };
+    return { decrypted: URL.createObjectURL(toBlob(result.data, getMimeTypeFromExt(audioExt))), ext: audioExt };
   }
 }