feat(downloads): add FLAC - Max Compression option and refactor transcoding logic

index.html

@@ -5117,11 +5117,7 @@
                                         <span class="label">Lossless Container</span>
                                         <span class="description">Container format for lossless downloads</span>
                                     </div>
-                                    <select id="lossless-container-setting">
-                                        <option value="flac">FLAC</option>
-                                        <option value="alac">Apple Lossless</option>
-                                        <option value="nochange">Don't change</option>
-                                    </select>
+                                    <select id="lossless-container-setting"></select>
                                 </div>
                                 <div class="setting-item">
                                     <div class="info">

js/api.js

@@ -12,9 +12,15 @@ import { addMetadataToAudio, prefetchMetadataObjects } from './metadata.js';
 import { DashDownloader } from './dash-downloader.js';
 import { HlsDownloader } from './hls-downloader.js';
 import { MP3EncodingError } from './mp3-encoder.js';
-import { ffmpeg, loadFfmpeg, FfmpegError } from './ffmpeg.js';
+import { loadFfmpeg, FfmpegError } from './ffmpeg.js';
 import { rebuildFlacWithoutMetadata } from './metadata.flac.js';
-import { isCustomFormat, getCustomFormat, transcodeWithCustomFormat } from './customFormats.ts';
+import {
+    isCustomFormat,
+    getCustomFormat,
+    transcodeWithCustomFormat,
+    getContainerFormat,
+    transcodeWithContainerFormat,
+} from './ffmpegFormats.ts';
 
 export const DASH_MANIFEST_UNAVAILABLE_CODE = 'DASH_MANIFEST_UNAVAILABLE';
 const TIDAL_V2_TOKEN = 'txNoH4kkV41MfH25';
@@ -1437,33 +1443,18 @@ export class LosslessAPI {
 
                 if (quality.endsWith('LOSSLESS')) {
                     try {
-                        switch (losslessContainerSettings.getContainer()) {
-                            case 'flac':
-                                if ((await getExtensionFromBlob(blob)) != 'flac') {
-                                    blob = await ffmpeg(
-                                        blob,
-                                        { args: ['-vn', '-map_metadata', '-1', '-map', '0:a', '-c:a', 'flac'] },
-                                        'output.flac',
-                                        'audio/flac',
-                                        onProgress,
-                                        options.signal
-                                    );
-                                } else {
-                                    blob = await rebuildFlacWithoutMetadata(blob);
-                                }
-                                break;
-                            case 'alac':
-                                blob = await ffmpeg(
+                        const containerFmt = getContainerFormat(losslessContainerSettings.getContainer());
+                        if (containerFmt) {
+                            if (await containerFmt.needsTranscode(blob)) {
+                                blob = await transcodeWithContainerFormat(
                                     blob,
-                                    { args: ['-c:a', 'alac'] },
-                                    'output.m4a',
-                                    'audio/mp4',
+                                    containerFmt,
                                     onProgress,
                                     options.signal
                                 );
-                                break;
-                            default:
-                                break;
+                            } else if ((await getExtensionFromBlob(blob)) == 'flac') {
+                                blob = await rebuildFlacWithoutMetadata(blob);
+                            }
                         }
                     } catch (error) {
                         if (error?.name === 'AbortError') {

js/customFormats.ts

@@ -1,148 +1,13 @@
-import { ffmpeg } from './ffmpeg';
-
-export interface ProgressEvent {
-    stage?: string;
-    message?: string;
-    progress?: number;
-    receivedBytes?: number;
-    totalBytes?: number;
-}
-
-export interface CustomFormat {
-    /** Human-readable label shown in the UI */
-    displayName: string;
-    /** Internal identifier, must start with `FFMPEG_` */
-    internalName: string;
-    /** Arguments passed to ffmpeg (excluding input/output file args) */
-    ffmpegArgs: string[];
-    /** Output filename used when calling ffmpeg */
-    outputFilename: string;
-    /** MIME type of the encoded output */
-    outputMime: string;
-    /** File extension of the encoded output */
-    extension: string;
-    /** Category label used for grouping in the UI (e.g. 'MP3', 'OGG', 'AAC') */
-    category: string;
-}
-
-export const customFormats: CustomFormat[] = [
-    {
-        displayName: 'MP3 320kbps',
-        internalName: 'FFMPEG_MP3_320',
-        ffmpegArgs: ['-map_metadata', '-1', '-c:a', 'libmp3lame', '-b:a', '320k', '-ar', '44100'],
-        outputFilename: 'output.mp3',
-        outputMime: 'audio/mpeg',
-        extension: 'mp3',
-        category: 'MP3',
-    },
-    {
-        displayName: 'MP3 256kbps',
-        internalName: 'FFMPEG_MP3_256',
-        ffmpegArgs: ['-map_metadata', '-1', '-c:a', 'libmp3lame', '-b:a', '256k', '-ar', '44100'],
-        outputFilename: 'output.mp3',
-        outputMime: 'audio/mpeg',
-        extension: 'mp3',
-        category: 'MP3',
-    },
-    {
-        displayName: 'MP3 128kbps',
-        internalName: 'FFMPEG_MP3_128',
-        ffmpegArgs: ['-map_metadata', '-1', '-c:a', 'libmp3lame', '-b:a', '128k', '-ar', '44100'],
-        outputFilename: 'output.mp3',
-        outputMime: 'audio/mpeg',
-        extension: 'mp3',
-        category: 'MP3',
-    },
-    {
-        displayName: 'OGG 320kbps',
-        internalName: 'FFMPEG_OGG_320',
-        ffmpegArgs: [
-            '-map_metadata',
-            '-1',
-            '-c:a',
-            'libvorbis',
-            '-b:a',
-            '320k',
-            '-minrate',
-            '320k',
-            '-maxrate',
-            '320k',
-        ],
-        outputFilename: 'output.ogg',
-        outputMime: 'audio/ogg',
-        extension: 'ogg',
-        category: 'OGG',
-    },
-    {
-        displayName: 'OGG 256kbps',
-        internalName: 'FFMPEG_OGG_256',
-        ffmpegArgs: [
-            '-map_metadata',
-            '-1',
-            '-c:a',
-            'libvorbis',
-            '-b:a',
-            '256k',
-            '-minrate',
-            '256k',
-            '-maxrate',
-            '256k',
-        ],
-        outputFilename: 'output.ogg',
-        outputMime: 'audio/ogg',
-        extension: 'ogg',
-        category: 'OGG',
-    },
-    {
-        displayName: 'OGG 128kbps',
-        internalName: 'FFMPEG_OGG_128',
-        ffmpegArgs: [
-            '-map_metadata',
-            '-1',
-            '-c:a',
-            'libvorbis',
-            '-b:a',
-            '128k',
-            '-minrate',
-            '128k',
-            '-maxrate',
-            '128k',
-        ],
-        outputFilename: 'output.ogg',
-        outputMime: 'audio/ogg',
-        extension: 'ogg',
-        category: 'OGG',
-    },
-    {
-        displayName: 'AAC 256kbps',
-        internalName: 'FFMPEG_AAC_256',
-        ffmpegArgs: ['-map_metadata', '-1', '-c:a', 'aac', '-b:a', '256k'],
-        outputFilename: 'output.m4a',
-        outputMime: 'audio/mp4',
-        extension: 'm4a',
-        category: 'AAC',
-    },
-];
-
-/** Returns true if the quality string identifies a known custom ffmpeg-transcoded format */
-export function isCustomFormat(quality: string): boolean {
-    return getCustomFormat(quality) !== undefined;
-}
-
-/** Looks up a custom format by its internal name, or returns undefined */
-export function getCustomFormat(internalName: string): CustomFormat | undefined {
-    return customFormats.find((f) => f.internalName === internalName);
-}
-
-/**
- * Transcodes an audio blob using the specified custom format via ffmpeg.
- * Throws if ffmpeg fails during transcoding.
- */
-export async function transcodeWithCustomFormat(
-    audioBlob: Blob,
-    format: CustomFormat,
-    onProgress: ((progress: ProgressEvent) => void) | null = null,
-    signal: AbortSignal | null = null
-): Promise<Blob> {
-    return ffmpeg(audioBlob, { args: format.ffmpegArgs }, format.outputFilename, format.outputMime, onProgress, signal);
-}
+// Re-exports for backwards compatibility – canonical source is ffmpegFormats.ts
+export {
+    type ProgressEvent,
+    type CustomFormat,
+    type ContainerFormat,
+    customFormats,
+    containerFormats,
+    isCustomFormat,
+    getCustomFormat,
+    getContainerFormat,
+    transcodeWithCustomFormat,
+    transcodeWithContainerFormat,
+} from './ffmpegFormats';

js/downloads.js

@@ -16,8 +16,14 @@ import { addMetadataToAudio, prefetchMetadataObjects } from './metadata.js';
 import { rebuildFlacWithoutMetadata } from './metadata.flac.js';
 import { DashDownloader } from './dash-downloader.js';
 import { generateM3U, generateM3U8, generateCUE, generateNFO, generateJSON } from './playlist-generator.js';
-import { ffmpeg, loadFfmpeg } from './ffmpeg.js';
-import { isCustomFormat, getCustomFormat, transcodeWithCustomFormat } from './customFormats.ts';
+import { loadFfmpeg } from './ffmpeg.js';
+import {
+    isCustomFormat,
+    getCustomFormat,
+    transcodeWithCustomFormat,
+    getContainerFormat,
+    transcodeWithContainerFormat,
+} from './ffmpegFormats.ts';
 
 const downloadTasks = new Map();
 const bulkDownloadTasks = new Map();
@@ -455,33 +461,13 @@ async function downloadTrackBlob(
 
     if (quality.endsWith('LOSSLESS')) {
         try {
-            switch (losslessContainerSettings.getContainer()) {
-                case 'flac':
-                    if ((await getExtensionFromBlob(blob)) != 'flac') {
-                        blob = await ffmpeg(
-                            blob,
-                            { args: ['-vn', '-map_metadata', '-1', '-map', '0:a', '-c:a', 'flac'] },
-                            'output.flac',
-                            'audio/flac',
-                            onProgress,
-                            signal
-                        );
-                    } else {
-                        blob = await rebuildFlacWithoutMetadata(blob);
-                    }
-                    break;
-                case 'alac':
-                    blob = await ffmpeg(
-                        blob,
-                        { args: ['-c:a', 'alac'] },
-                        'output.m4a',
-                        'audio/mp4',
-                        onProgress,
-                        signal
-                    );
-                    break;
-                default:
-                    break;
+            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);
+                }
             }
         } catch (error) {
             if (error?.name === 'AbortError') {

js/ffmpegFormats.ts

@@ -0,0 +1,229 @@
+import { ffmpeg } from './ffmpeg';
+import { getExtensionFromBlob } from './utils';
+
+export interface ProgressEvent {
+    stage?: string;
+    message?: string;
+    progress?: number;
+    receivedBytes?: number;
+    totalBytes?: number;
+}
+
+export interface CustomFormat {
+    /** Human-readable label shown in the UI */
+    displayName: string;
+    /** Internal identifier, must start with `FFMPEG_` */
+    internalName: string;
+    /** Arguments passed to ffmpeg (excluding input/output file args) */
+    ffmpegArgs: string[];
+    /** Output filename used when calling ffmpeg */
+    outputFilename: string;
+    /** MIME type of the encoded output */
+    outputMime: string;
+    /** File extension of the encoded output */
+    extension: string;
+    /** Category label used for grouping in the UI (e.g. 'MP3', 'OGG', 'AAC') */
+    category: string;
+}
+
+/**
+ * A container format definition for lossless re-muxing/re-encoding.
+ * Extends CustomFormat with a callback that decides whether ffmpeg needs to run
+ * at all (e.g. FLAC can skip if the source is already FLAC).
+ */
+export interface ContainerFormat extends Omit<CustomFormat, 'category'> {
+    /**
+     * Returns true when the source blob must be passed through ffmpeg to produce
+     * the desired container.  Return false to skip the ffmpeg step (the caller
+     * may still apply a lightweight metadata-strip pass instead).
+     */
+    needsTranscode: (blob: Blob) => Promise<boolean>;
+}
+
+export const customFormats: CustomFormat[] = [
+    {
+        displayName: 'MP3 320kbps',
+        internalName: 'FFMPEG_MP3_320',
+        ffmpegArgs: ['-map_metadata', '-1', '-c:a', 'libmp3lame', '-b:a', '320k', '-ar', '44100'],
+        outputFilename: 'output.mp3',
+        outputMime: 'audio/mpeg',
+        extension: 'mp3',
+        category: 'MP3',
+    },
+    {
+        displayName: 'MP3 256kbps',
+        internalName: 'FFMPEG_MP3_256',
+        ffmpegArgs: ['-map_metadata', '-1', '-c:a', 'libmp3lame', '-b:a', '256k', '-ar', '44100'],
+        outputFilename: 'output.mp3',
+        outputMime: 'audio/mpeg',
+        extension: 'mp3',
+        category: 'MP3',
+    },
+    {
+        displayName: 'MP3 128kbps',
+        internalName: 'FFMPEG_MP3_128',
+        ffmpegArgs: ['-map_metadata', '-1', '-c:a', 'libmp3lame', '-b:a', '128k', '-ar', '44100'],
+        outputFilename: 'output.mp3',
+        outputMime: 'audio/mpeg',
+        extension: 'mp3',
+        category: 'MP3',
+    },
+    {
+        displayName: 'OGG 320kbps',
+        internalName: 'FFMPEG_OGG_320',
+        ffmpegArgs: [
+            '-map_metadata',
+            '-1',
+            '-c:a',
+            'libvorbis',
+            '-b:a',
+            '320k',
+            '-minrate',
+            '320k',
+            '-maxrate',
+            '320k',
+        ],
+        outputFilename: 'output.ogg',
+        outputMime: 'audio/ogg',
+        extension: 'ogg',
+        category: 'OGG',
+    },
+    {
+        displayName: 'OGG 256kbps',
+        internalName: 'FFMPEG_OGG_256',
+        ffmpegArgs: [
+            '-map_metadata',
+            '-1',
+            '-c:a',
+            'libvorbis',
+            '-b:a',
+            '256k',
+            '-minrate',
+            '256k',
+            '-maxrate',
+            '256k',
+        ],
+        outputFilename: 'output.ogg',
+        outputMime: 'audio/ogg',
+        extension: 'ogg',
+        category: 'OGG',
+    },
+    {
+        displayName: 'OGG 128kbps',
+        internalName: 'FFMPEG_OGG_128',
+        ffmpegArgs: [
+            '-map_metadata',
+            '-1',
+            '-c:a',
+            'libvorbis',
+            '-b:a',
+            '128k',
+            '-minrate',
+            '128k',
+            '-maxrate',
+            '128k',
+        ],
+        outputFilename: 'output.ogg',
+        outputMime: 'audio/ogg',
+        extension: 'ogg',
+        category: 'OGG',
+    },
+    {
+        displayName: 'AAC 256kbps',
+        internalName: 'FFMPEG_AAC_256',
+        ffmpegArgs: ['-map_metadata', '-1', '-c:a', 'aac', '-b:a', '256k'],
+        outputFilename: 'output.m4a',
+        outputMime: 'audio/mp4',
+        extension: 'm4a',
+        category: 'AAC',
+    },
+];
+
+/**
+ * Container format definitions for lossless re-muxing.  Each entry describes
+ * the ffmpeg arguments needed to produce that container and provides a
+ * `needsTranscode` predicate so callers can skip the ffmpeg step when the
+ * source is already in the correct container.
+ */
+export const containerFormats: ContainerFormat[] = [
+    {
+        displayName: 'FLAC',
+        internalName: 'flac',
+        ffmpegArgs: ['-vn', '-map_metadata', '-1', '-map', '0:a', '-c:a', 'flac', '-compression_level', '12'],
+        outputFilename: 'output.flac',
+        outputMime: 'audio/flac',
+        extension: 'flac',
+        // Only transcode when the source is NOT already a FLAC file.
+        needsTranscode: async (blob) => (await getExtensionFromBlob(blob)) !== 'flac',
+    },
+    {
+        displayName: 'FLAC - Max Compression',
+        internalName: 'flac_max',
+        // `-compression_level 12` is the highest FLAC compression level; audio
+        // data is bit-identical to the source — only the compressed size changes.
+        ffmpegArgs: ['-vn', '-map_metadata', '-1', '-map', '0:a', '-c:a', 'flac', '-compression_level', '12'],
+        outputFilename: 'output.flac',
+        outputMime: 'audio/flac',
+        extension: 'flac',
+        needsTranscode: async () => true,
+    },
+    {
+        displayName: 'Apple Lossless',
+        internalName: 'alac',
+        ffmpegArgs: ['-c:a', 'alac'],
+        outputFilename: 'output.m4a',
+        outputMime: 'audio/mp4',
+        extension: 'm4a',
+        needsTranscode: async () => true,
+    },
+    {
+        displayName: "Don't change",
+        internalName: 'nochange',
+        ffmpegArgs: [],
+        outputFilename: '',
+        outputMime: '',
+        extension: '',
+        needsTranscode: async () => false,
+    },
+];
+
+/** Returns true if the quality string identifies a known custom ffmpeg-transcoded format */
+export function isCustomFormat(quality: string): boolean {
+    return getCustomFormat(quality) !== undefined;
+}
+
+/** Looks up a custom format by its internal name, or returns undefined */
+export function getCustomFormat(internalName: string): CustomFormat | undefined {
+    return customFormats.find((f) => f.internalName === internalName);
+}
+
+/** Looks up a container format by its internal name, or returns undefined */
+export function getContainerFormat(internalName: string): ContainerFormat | undefined {
+    return containerFormats.find((f) => f.internalName === internalName);
+}
+
+/**
+ * Transcodes an audio blob using the specified custom format via ffmpeg.
+ * Throws if ffmpeg fails during transcoding.
+ */
+export async function transcodeWithCustomFormat(
+    audioBlob: Blob,
+    format: CustomFormat,
+    onProgress: ((progress: ProgressEvent) => void) | null = null,
+    signal: AbortSignal | null = null
+): Promise<Blob> {
+    return ffmpeg(audioBlob, { args: format.ffmpegArgs }, format.outputFilename, format.outputMime, onProgress, signal);
+}
+
+/**
+ * Re-muxes / re-encodes an audio blob into the specified container format via ffmpeg.
+ * Throws if ffmpeg fails during transcoding.
+ */
+export async function transcodeWithContainerFormat(
+    audioBlob: Blob,
+    format: ContainerFormat,
+    onProgress: ((progress: ProgressEvent) => void) | null = null,
+    signal: AbortSignal | null = null
+): Promise<Blob> {
+    return ffmpeg(audioBlob, { args: format.ffmpegArgs }, format.outputFilename, format.outputMime, onProgress, signal);
+}

js/settings.js

@@ -42,7 +42,7 @@ import { db } from './db.js';
 import { authManager } from './accounts/auth.js';
 import { syncManager } from './accounts/pocketbase.js';
 import { saveFirebaseConfig, clearFirebaseConfig } from './accounts/config.js';
-import { customFormats } from './customFormats.ts';
+import { containerFormats, customFormats } from './ffmpegFormats.ts';
 
 export function initializeSettings(scrobbler, player, api, ui) {
     // Restore last active settings tab
@@ -867,6 +867,13 @@ export function initializeSettings(scrobbler, player, api, ui) {
 
     const losslessContainerSetting = document.getElementById('lossless-container-setting');
     if (losslessContainerSetting) {
+        for (const { internalName, displayName } of containerFormats) {
+            const option = document.createElement('option');
+            option.value = internalName;
+            option.textContent = displayName;
+            losslessContainerSetting.appendChild(option);
+        }
+
         losslessContainerSetting.value = losslessContainerSettings.getContainer();
 
         losslessContainerSetting.addEventListener('change', (e) => {