refactor(downloads/ffmpeg): refactor ffmpeg usage and add additional logging for ffmpeg

index.html

@@ -5139,7 +5139,9 @@
                                         <span class="label">Lossless Container</span>
                                         <span class="description">Container format for lossless downloads</span>
                                     </div>
-                                    <select id="lossless-container-setting"></select>
+                                    <select id="lossless-container-setting">
+                                        <option value="nochange">Don't change</option>
+                                    </select>
                                 </div>
                                 <div class="setting-item">
                                     <div class="info">

js/download-utils.ts

@@ -1,6 +1,6 @@
 import { losslessContainerSettings } from './storage';
-import { rebuildFlacWithoutMetadata } from './metadata.flac';
 import { getExtensionFromBlob } from './utils';
+import { rebuildFlacWithoutMetadata } from './metadata.flac.js';
 import {
     type ProgressEvent,
     isCustomFormat,
@@ -9,7 +9,7 @@ import {
     getContainerFormat,
     transcodeWithContainerFormat,
 } from './ffmpegFormats';
-import { ffmpeg } from './ffmpeg';
+import { ffmpegNewContainer } from './ffmpeg';
 
 /**
  * Triggers a browser file download for the given blob.
@@ -60,12 +60,20 @@ export async function applyAudioPostProcessing(
     if (quality.endsWith('LOSSLESS')) {
         try {
             const containerFmt = getContainerFormat(losslessContainerSettings.getContainer());
-            if (containerFmt) {
-                if (await containerFmt.needsTranscode(blob)) {
-                    blob = await transcodeWithContainerFormat(blob, containerFmt, onProgress, signal);
-                } else if ((await getExtensionFromBlob(blob)) === 'flac') {
-                    blob = await rebuildFlacWithoutMetadata(blob);
-                }
+            const extension = await getExtensionFromBlob(blob);
+
+            if (await containerFmt?.needsTranscode(blob)) {
+                blob = await transcodeWithContainerFormat(blob, containerFmt, onProgress, signal);
+            } else if (extension == 'flac') {
+                blob = await rebuildFlacWithoutMetadata(blob);
+            } else {
+                blob = await ffmpegNewContainer(
+                    blob,
+                    extension == 'm4a' ? 'mp4' : extension,
+                    blob.type,
+                    onProgress,
+                    signal
+                );
             }
         } catch (error) {
             if ((error as Error)?.name === 'AbortError') {

js/ffmpeg.js

@@ -27,7 +27,7 @@ export function loadFfmpeg() {
 
 async function ffmpegWorker(
     audioBlob,
-    args = {},
+    args = [],
     outputName = 'output',
     outputMime = 'application/octet-stream',
     onProgress = null,
@@ -93,7 +93,7 @@ async function ffmpegWorker(
                 {
                     audioData,
                     extraFiles,
-                    ...args,
+                    args,
                     output: {
                         name: outputName,
                         mime: outputMime,
@@ -108,7 +108,7 @@ async function ffmpegWorker(
 
 export async function ffmpeg(
     audioBlob,
-    args = {},
+    args = [],
     outputName = 'output',
     outputMime = 'application/octet-stream',
     onProgress = null,
@@ -128,4 +128,24 @@ export async function ffmpeg(
     }
 }
 
+/**
+ * Creates a new FFmpeg container with copied codec and stripped metadata.
+ * @param {Blob} audioBlob - The audio blob to process
+ * @param {string} outputExtension - The extension for the output file
+ * @param {string} outputMime - The MIME type for the output blob
+ * @param {Function} onProgress - Callback function to track conversion progress
+ * @param {AbortSignal} signal - AbortSignal for cancelling the operation
+ * @returns {Promise<Blob>} A promise that resolves to the processed data blob
+ */
+export async function ffmpegNewContainer(audioBlob, outputExtension, outputMime, onProgress, signal) {
+    return await ffmpeg(
+        audioBlob,
+        ['-map_metadata', '-1', '-c', 'copy', '-strict', '-2'],
+        `output.${outputExtension}`,
+        outputMime,
+        onProgress,
+        signal
+    );
+}
+
 export { FfmpegError };

js/ffmpeg.worker.js

@@ -141,15 +141,21 @@ self.onmessage = async (e) => {
         } finally {
             try {
                 if (audioData) await ffmpeg.deleteFile('input');
-            } catch {}
+            } catch {
+                self.postMessage({ type: 'log', message: 'Failed to delete input file from FFmpeg FS.' });
+            }
             for (const file of extraFiles) {
                 try {
                     await ffmpeg.deleteFile(file.name);
-                } catch {}
+                } catch {
+                    self.postMessage({ type: 'log', message: `Failed to delete ${file.name} from FFmpeg FS.` });
+                }
             }
             try {
                 await ffmpeg.deleteFile(output.name);
-            } catch {}
+            } catch {
+                self.postMessage({ type: 'log', message: `Failed to delete ${output.name} from FFmpeg FS.` });
+            }
         }
     } catch (error) {
         self.postMessage({ type: 'error', message: error.message });

js/ffmpegFormats.ts

@@ -154,14 +154,6 @@ export const containerFormats: Record<string, ContainerFormat> = {
         extension: 'm4a',
         needsTranscode: async () => true,
     },
-    nochange: {
-        displayName: "Don't change",
-        ffmpegArgs: ['-c:a', 'copy', '-strict', '-2'],
-        outputFilename: 'output.mp4',
-        outputMime: 'audio/mp4',
-        extension: 'mp4',
-        needsTranscode: async (blob) => (await getExtensionFromBlob(blob)) == 'm4a',
-    },
 };
 
 /** Returns true if the quality string identifies a known custom ffmpeg-transcoded format */
@@ -192,7 +184,7 @@ export async function transcodeWithCustomFormat(
 ): Promise<Blob> {
     return ffmpeg(
         audioBlob,
-        { args: format.ffmpegArgs },
+        format.ffmpegArgs,
         format.outputFilename,
         format.outputMime,
         onProgress,
@@ -214,7 +206,7 @@ export async function transcodeWithContainerFormat(
 ): Promise<Blob> {
     return ffmpeg(
         audioBlob,
-        { args: format.ffmpegArgs },
+        format.ffmpegArgs,
         format.outputFilename,
         format.outputMime,
         onProgress,

js/settings.js

@@ -877,6 +877,9 @@ export function initializeSettings(scrobbler, player, api, ui) {
     }
 
     if (losslessContainerSetting) {
+        const noChangeOption = losslessContainerSetting.querySelector('option:last-child');
+        noChangeOption.remove();
+
         for (const [internalName, { displayName }] of Object.entries(containerFormats)) {
             const option = document.createElement('option');
             option.value = internalName;
@@ -884,6 +887,8 @@ export function initializeSettings(scrobbler, player, api, ui) {
             losslessContainerSetting.appendChild(option);
         }
 
+        losslessContainerSetting.append(noChangeOption);
+
         losslessContainerSetting.value = losslessContainerSettings.getContainer();
 
         losslessContainerSetting.addEventListener('change', (e) => {