Apply AAC remux filters only to matching audio tracks

Adapted from MikaelKW/nodecast-tv-plus commit 25f7cb636a07a3efb2c409ff182920ae0fbe01bd.

Co-authored-by: Mikael <mikaelkwessel@gmail.com>

public/js/components/VideoPlayer.js

@@ -859,6 +859,8 @@ class VideoPlayer {
 
             // Stop current playback
             this.stop();
+            const playbackGeneration = this.playbackGeneration;
+            let probeInfo = null;
             this.updateTranscodeStatus('hidden');
 
             // Hide "select a channel" overlay
@@ -877,6 +879,8 @@ class VideoPlayer {
                 try {
                     const probeRes = await fetch(`/api/probe?url=${encodeURIComponent(streamUrl)}`);
                     const info = await probeRes.json();
+                    if (this.playbackGeneration !== playbackGeneration) return;
+                    probeInfo = info;
                     console.log(`[Player] Probe result: video=${info.video}, audio=${info.audio}, ${info.width}x${info.height}, compatible=${info.compatible}`);
 
                     // Store probe result for quality badge display
@@ -936,7 +940,7 @@ class VideoPlayer {
                         // Raw .ts container - use remux
                         console.log('[Player] Auto: Using remux (.ts container)');
                         this.updateTranscodeStatus('remuxing', 'Remux (Auto)');
-                        const remuxUrl = `/api/remux?url=${encodeURIComponent(streamUrl)}`;
+                        const remuxUrl = this.getRemuxUrl(streamUrl, info.audioCodecs || [info.audio]);
                         this.currentUrl = remuxUrl;
                         this.video.src = remuxUrl;
                         this.video.play().catch(e => {
@@ -1055,7 +1059,17 @@ class VideoPlayer {
                 console.log('[Player] Force Remux enabled. Routing through FFmpeg remux...');
                 console.log('[Player] Stream type:', isRawTs ? 'Raw TS' : 'Extension-less (assumed TS)');
                 this.updateTranscodeStatus('remuxing', 'Remux (Force)');
-                const remuxUrl = this.getRemuxUrl(streamUrl);
+                if (!probeInfo) {
+                    try {
+                        const response = await fetch(`/api/probe?url=${encodeURIComponent(streamUrl)}`);
+                        probeInfo = await response.json();
+                    } catch (error) {
+                        console.warn('[Player] Remux probe failed:', error.message);
+                    }
+                }
+                if (this.playbackGeneration !== playbackGeneration) return;
+                const remuxUrl = this.getRemuxUrl(streamUrl, probeInfo?.audioCodecs || (probeInfo?.audio ? [probeInfo.audio] : []));
+                this.currentUrl = remuxUrl;
                 this.video.src = remuxUrl;
                 this.video.play().catch(e => {
                     if (e.name !== 'AbortError') console.log('[Player] Autoplay prevented:', e);
@@ -1369,8 +1383,8 @@ class VideoPlayer {
      * Get remuxed URL for a stream (container conversion only, no re-encoding)
      * Used for raw .ts streams that browsers can't play directly
      */
-    getRemuxUrl(url) {
+    getRemuxUrl(url, audioCodecs = []) {
-        return `/api/remux?url=${encodeURIComponent(url)}`;
+        return `/api/remux?url=${encodeURIComponent(url)}&audioCodecs=${encodeURIComponent(audioCodecs.join(','))}`;
     }
 
     /**
@@ -1389,6 +1403,7 @@ class VideoPlayer {
      * Stop playback
      */
     stop() {
+        this.playbackGeneration = (this.playbackGeneration || 0) + 1;
         // Stop any running transcode session first
         this.stopTranscodeSession();
 

public/js/pages/WatchPage.js

@@ -415,6 +415,8 @@ class WatchPage {
 
         // Stop any existing playback
         this.stop();
+        const playbackGeneration = this.playbackGeneration;
+        let probeInfo = null;
 
         // Show loading spinner
         this.showLoading();
@@ -439,6 +441,8 @@ class WatchPage {
                 const ua = settings.userAgentPreset === 'custom' ? settings.userAgentCustom : settings.userAgentPreset;
                 const probeRes = await fetch(`/api/probe?url=${encodeURIComponent(url)}&ua=${encodeURIComponent(ua || '')}`);
                 const info = await probeRes.json();
+                if (this.playbackGeneration !== playbackGeneration) return;
+                probeInfo = info;
                 console.log(`[WatchPage] Probe result: video=${info.video}, audio=${info.audio}, ${info.width}x${info.height}, compatible=${info.compatible}`);
 
                 // Store early probe info for quality display
@@ -471,7 +475,7 @@ class WatchPage {
                     // TODO: Move remux to session logic if seeking is needed for TS files
                     console.log('[WatchPage] Auto: Using remux (.ts container)');
                     this.updateTranscodeStatus('remuxing', 'Remux (Auto)');
-                    const finalUrl = `/api/remux?url=${encodeURIComponent(url)}`;
+                    const finalUrl = this.getRemuxUrl(url, info.audioCodecs || [info.audio]);
                     this.video.src = finalUrl;
                     this.video.play().catch(e => {
                         if (e.name !== 'AbortError') console.error('[WatchPage] Autoplay error:', e);
@@ -529,7 +533,17 @@ class WatchPage {
         if (settings.forceRemux && isRawTs) {
             console.log('[WatchPage] Force Remux enabled');
             this.updateTranscodeStatus('remuxing', 'Remux (Force)');
-            const finalUrl = `/api/remux?url=${encodeURIComponent(url)}`;
+            if (!probeInfo) {
+                try {
+                    const ua = settings.userAgentPreset === 'custom' ? settings.userAgentCustom : settings.userAgentPreset;
+                    const response = await fetch(`/api/probe?url=${encodeURIComponent(url)}&ua=${encodeURIComponent(ua || '')}`);
+                    probeInfo = await response.json();
+                } catch (error) {
+                    console.warn('[WatchPage] Remux probe failed:', error.message);
+                }
+            }
+            if (this.playbackGeneration !== playbackGeneration) return;
+            const finalUrl = this.getRemuxUrl(url, probeInfo?.audioCodecs || (probeInfo?.audio ? [probeInfo.audio] : []));
             this.video.src = finalUrl;
             this.video.play().catch(e => {
                 if (e.name !== 'AbortError') console.error('[WatchPage] Autoplay error:', e);
@@ -617,7 +631,12 @@ class WatchPage {
         if (this.volumeSlider) this.volumeSlider.value = savedVolume;
     }
 
+    getRemuxUrl(url, audioCodecs = []) {
+        return `/api/remux?url=${encodeURIComponent(url)}&audioCodecs=${encodeURIComponent(audioCodecs.join(','))}`;
+    }
+
     stop() {
+        this.playbackGeneration = (this.playbackGeneration || 0) + 1;
         // Stop history tracking and save final progress
         this.stopHistoryTracking();
         this.saveProgress();

server/routes/probe.js

@@ -133,6 +133,8 @@ function analyzeProbeResult(probeResult, url) {
     return {
         video: videoCodec,
         audio: audioCodec,
+        audioCodecs: streams.filter(s => s.codec_type === 'audio')
+            .map(s => s.codec_name?.toLowerCase() || 'unknown'),
         width: videoStream?.width || 0,
         height: videoStream?.height || 0,
         audioChannels: audioStream?.channels || 0, // For Smart Audio Copy

server/routes/remux.js

@@ -2,6 +2,7 @@ const express = require('express');
 const router = express.Router();
 const { spawn } = require('child_process');
 const db = require('../db');
+const { parseAudioCodecs, audioFilterArgs } = require('../services/remuxAudio');
 
 /**
  * Allowed input URL schemes for the remux endpoint.
@@ -70,6 +71,13 @@ router.get('/', async (req, res) => {
         return res.status(400).json({ error: 'URL must be an http:// or https:// stream URL' });
     }
 
+    let audioCodecs;
+    try {
+        audioCodecs = parseAudioCodecs(req.query.audioCodecs);
+    } catch (error) {
+        return res.status(400).json({ error: error.message });
+    }
+
     const ffmpegPath = req.app.locals.ffmpegPath || 'ffmpeg';
 
     // Get User-Agent from settings
@@ -118,9 +126,8 @@ router.get('/', async (req, res) => {
         '-c', 'copy',
         // Ensure extradata is correctly extracted/converted (fixes Annex B -> AVCC issues in Firefox)
         '-bsf:v', 'dump_extra',
-        // NOTE: We intentionally do NOT use -bsf:a aac_adtstoasc here
+        // Convert ADTS only on probed AAC tracks; leave MP3/AC3/EAC3 untouched.
-        // That filter only works for AAC audio and breaks AC3/EAC3/MP3.
+        ...audioFilterArgs(audioCodecs),
-        // If AAC audio from MPEG-TS fails in MP4, use /api/transcode instead.
         // Handle timestamp discontinuities at output
         '-fps_mode', 'passthrough',
         '-max_muxing_queue_size', '1024',

server/services/remuxAudio.js

@@ -0,0 +1,17 @@
+// Preserve audio stream order: -map 0:a maps every input audio track.
+function parseAudioCodecs(value) {
+    if (value === undefined || value === '') return [];
+    if (typeof value !== 'string') throw new Error('audioCodecs must be a comma-separated string');
+    const codecs = value.split(',').map(codec => codec.trim().toLowerCase());
+    if (codecs.length > 16 || codecs.some(codec => !/^[a-z0-9][a-z0-9_.-]{0,31}$/.test(codec))) {
+        throw new Error('audioCodecs contains invalid codec names');
+    }
+    return codecs;
+}
+
+function audioFilterArgs(codecs) {
+    return codecs.flatMap((codec, index) => codec === 'aac'
+        ? [`-bsf:a:${index}`, 'aac_adtstoasc'] : []);
+}
+
+module.exports = { parseAudioCodecs, audioFilterArgs };

test/remux-playback.test.js

@@ -0,0 +1,73 @@
+const test = require('node:test');
+const assert = require('node:assert/strict');
+const fs = require('node:fs');
+const path = require('node:path');
+const vm = require('node:vm');
+const { createRequire } = require('node:module');
+
+test('probe preserves every audio track index including unknown codecs', () => {
+    const filename = path.join(__dirname, '..', 'server/routes/probe.js');
+    const context = vm.createContext({ require: createRequire(filename), module: { exports: {} }, console });
+    vm.runInContext(fs.readFileSync(filename, 'utf8'), context, { filename });
+    const info = context.analyzeProbeResult({ streams: [
+        { codec_type: 'video', codec_name: 'h264' },
+        { codec_type: 'audio', codec_name: 'mp3' },
+        { codec_type: 'subtitle', codec_name: 'srt' },
+        { codec_type: 'audio' }, { codec_type: 'audio', codec_name: 'AAC' }
+    ], format: { format_name: 'mpegts' } }, 'http://provider.test/media.ts');
+    assert.deepEqual(Array.from(info.audioCodecs), ['mp3', 'unknown', 'aac']);
+    assert.equal(info.needsRemux, true);
+});
+
+function playerFixture(name, settings, probe) {
+    const window = { dispatchEvent() {} };
+    const context = { window, console: { log() {}, warn() {}, error() {} },
+        CustomEvent: class {}, document: { getElementById() { return null; } },
+        API: { settings: { get: async () => settings } }, fetch: probe };
+    const file = name === 'VideoPlayer' ? 'components/VideoPlayer.js' : 'pages/WatchPage.js';
+    vm.runInNewContext(fs.readFileSync(path.join(__dirname, '..', 'public/js', file), 'utf8'), context);
+    const player = Object.create(window[name].prototype);
+    const element = { classList: { add() {}, remove() {} } };
+    Object.assign(player, { settings, video: { src: '', play: async () => {}, querySelectorAll: () => [] },
+        overlay: element, nowPlaying: element,
+        stop() { this.playbackGeneration = (this.playbackGeneration || 0) + 1; this.video.src = ''; },
+        updateTranscodeStatus() {}, updateQualityBadge() {}, updateNowPlaying() {},
+        showNowPlayingOverlay() {}, fetchEpgData() {}, setVolumeFromStorage() {}, showLoading() {},
+        showError(message) { throw new Error(message); }
+    });
+    player.start = url => name === 'VideoPlayer' ? player.play({ id: url }, url) : player.loadVideo(url);
+    return player;
+}
+
+for (const name of ['VideoPlayer', 'WatchPage']) {
+    for (const mode of ['autoTranscode', 'forceRemux']) {
+        test(`${name} ${mode} propagates mixed audio codecs to the remux request`, async () => {
+            const requests = [];
+            const player = playerFixture(name, { [mode]: true }, async url => {
+                requests.push(url);
+                return { json: async () => ({ audio: 'mp3', audioCodecs: ['mp3', 'aac'], needsRemux: true }) };
+            });
+            const url = 'http://provider.test/media.ts?password=abc/';
+            await player.start(url);
+            const remux = new URL(player.video.src, 'http://app.test');
+            assert.equal(remux.pathname, '/api/remux');
+            assert.equal(remux.searchParams.get('url'), url);
+            assert.equal(remux.searchParams.get('audioCodecs'), 'mp3,aac');
+            assert.equal(requests.length, 1);
+        });
+    }
+    test(`${name} ignores a remux probe that completes after playback stops`, async () => {
+        let complete, started;
+        const probing = new Promise(resolve => { started = resolve; });
+        const player = playerFixture(name, { forceRemux: true }, () => {
+            started();
+            return new Promise(resolve => { complete = resolve; });
+        });
+        const playing = player.start('http://provider.test/media.ts');
+        await probing;
+        player.stop();
+        complete({ json: async () => ({ audioCodecs: ['aac'] }) });
+        await playing;
+        assert.equal(player.video.src, '');
+    });
+}

test/remux.test.js

@@ -112,6 +112,22 @@ test('remux accepts HTTP(S), preserves query credentials, and restricts nested p
     }
 });
 
+test('remux filters only AAC output tracks and rejects malformed codec hints', async t => {
+    const { base, calls } = await routeFixture(t);
+    const url = `${base}/api/remux?url=http%3A%2F%2Fprovider.test%2Fmedia.ts`;
+    assert.equal((await request(`${url}&audioCodecs=mp3%2CAAC%2Cunknown%2Caac%2Cac3`)).status, 200);
+    const args = calls.at(-1).args;
+    assert.equal(args[args.indexOf('-bsf:a:1') + 1], 'aac_adtstoasc');
+    assert.equal(args[args.indexOf('-bsf:a:3') + 1], 'aac_adtstoasc');
+    assert.equal(args.filter(arg => arg.startsWith('-bsf:a')).length, 2);
+    for (const query of ['audioCodecs=aac&audioCodecs=mp3', 'audioCodecs[x]=aac',
+        'audioCodecs=aac,,mp3', 'audioCodecs=-i',
+        `audioCodecs=${Array(17).fill('aac').join(',')}`]) {
+        assert.equal((await request(`${url}&${query}`)).status, 400, query);
+    }
+    assert.equal(calls.length, 1);
+});
+
 function findFFmpeg() {
     // Match server/index.js: prefer system FFmpeg, then the optional binary.
     if (spawnSync('ffmpeg', ['-version'], { stdio: 'ignore' }).status === 0) return 'ffmpeg';
@@ -153,11 +169,17 @@ test('real FFmpeg remuxes encrypted HLS over HTTP and blocks local HLS segments'
             '-c:v', 'libx264', '-threads', '1', '-preset', 'ultrafast', '-tune', 'zerolatency',
             '-c:a', 'libmp3lame', '-f', 'mpegts', sample]);
         assert.equal(generated.code, 0, generated.stderr);
+        const mixedSample = path.join(dir, 'mixed.ts');
+        const mixedGenerated = await runFFmpeg(ffmpeg, ['-hide_banner', '-loglevel', 'error', '-y',
+            '-i', sample, '-map', '0:v', '-map', '0:a', '-map', '0:a',
+            '-c:v', 'copy', '-c:a:0', 'libmp3lame', '-c:a:1', 'aac', '-f', 'mpegts', mixedSample]);
+        assert.equal(mixedGenerated.code, 0, mixedGenerated.stderr);
         const media = fs.readFileSync(sample), key = Buffer.alloc(16, 0x5a), iv = Buffer.alloc(16);
         const cipher = crypto.createCipheriv('aes-128-cbc', key, iv);
         const header = '#EXTM3U\n#EXT-X-VERSION:3\n#EXT-X-TARGETDURATION:12\n#EXT-X-MEDIA-SEQUENCE:0\n';
         const resources = {
             '/media.ts': media,
+            '/mixed.ts': fs.readFileSync(mixedSample),
             '/key.bin': key,
             '/encrypted.ts': Buffer.concat([cipher.update(media), cipher.final()]),
             '/plain.m3u8': Buffer.from(`${header}#EXTINF:12,\nmedia.ts\n#EXT-X-ENDLIST\n`),
@@ -174,9 +196,10 @@ test('real FFmpeg remuxes encrypted HLS over HTTP and blocks local HLS segments'
         t.after(() => new Promise(resolve => server.close(resolve)));
         const base = await listen(server);
         const { base: routeBase, calls } = await routeFixture(t);
-        for (const file of ['media.ts', 'plain.m3u8', 'encrypted.m3u8', 'local.m3u8']) {
+        for (const file of ['media.ts', 'mixed.ts', 'plain.m3u8', 'encrypted.m3u8', 'local.m3u8']) {
             const url = `${base}/${file}`;
-            assert.equal((await request(`${routeBase}/api/remux?url=${encodeURIComponent(url)}`)).status, 200);
+            const hints = file === 'mixed.ts' ? '&audioCodecs=mp3,aac' : '';
+            assert.equal((await request(`${routeBase}/api/remux?url=${encodeURIComponent(url)}${hints}`)).status, 200);
             const result = await runFFmpeg(ffmpeg, calls.at(-1).args);
             assert.equal(result.timedOut, false, file);
             if (file === 'local.m3u8') {
@@ -187,6 +210,13 @@ test('real FFmpeg remuxes encrypted HLS over HTTP and blocks local HLS segments'
                 assert.equal(result.code, 0, `${file} (${ffmpeg}, signal=${result.signal}): ${result.stderr}`);
                 assert.ok(result.stdout.includes(Buffer.from('ftyp')), `${file}: no MP4 output`);
                 assert.ok(result.stdout.includes(Buffer.from('mdat')), `${file}: no media packets`);
+                if (file === 'mixed.ts') {
+                    const output = path.join(dir, 'mixed.mp4');
+                    fs.writeFileSync(output, result.stdout);
+                    const decoded = await runFFmpeg(ffmpeg, ['-hide_banner', '-loglevel', 'error',
+                        '-i', output, '-map', '0:a', '-f', 'null', '-']);
+                    assert.equal(decoded.code, 0, decoded.stderr);
+                }
             }
         }
     });