feat: Implement hardware-accelerated HLS transcoding with granular controls, smart stereo downmixing, and robust support for MKV and 10-bit HEVC playback.

server/routes/probe.js

@@ -112,11 +112,15 @@ function analyzeProbeResult(probeResult, url) {
         }));
 
     // Determine what processing is needed
-    // 1. Incompatible audio -> Transcode (highest priority)
-    const needsTranscode = !audioOk;
+    // 4. MKV files often cause OOM/decoding issues in browser fMP4 remux, 
+    // so we force them to "needsTranscode" which uses HLS (more robust).
+    // The frontend will still use "copy" mode if codecs are compatible.
+    const isMkv = container.includes('matroska') || container.includes('webm') || url.endsWith('.mkv');
 
-    // 2. Compatible audio/video but incompatible container -> Remux
-    // This catches raw TS, MKV, AVI, etc. that have H.264/AAC but wrong container
+    // 1. Incompatible audio/video OR MKV -> Transcode (or HLS Copy)
+    const needsTranscode = !audioOk || !videoOk || isMkv;
+
+    // 2. Compatible audio/video but incompatible container (non-MKV) -> Remux (fMP4 pipe)
     const needsRemux = !needsTranscode && (!containerOk || isRawTs);
 
     const compatible = !needsTranscode && !needsRemux;

server/routes/remux.js

@@ -34,9 +34,10 @@ router.get('/', async (req, res) => {
         '-hide_banner',
         '-loglevel', 'warning',
         '-user_agent', userAgent,
-        // Low-latency startup: reduce probe/analyze time for faster first bytes
-        '-probesize', '32768',
-        '-analyzeduration', '500000', // 0.5 seconds - enough to detect audio
+        '-user_agent', userAgent,
+        // Standard probe size to handle complex containers (MKV) correctly
+        '-probesize', '5000000',
+        '-analyzeduration', '5000000',
         // Error resilience: discard corrupt packets, generate timestamps, ignore DTS, no buffering
         '-fflags', '+genpts+discardcorrupt+igndts+nobuffer',
         // Ignore errors in stream and continue
@@ -58,6 +59,8 @@ router.get('/', async (req, res) => {
         '-sn', '-dn',
         // Copy streams without re-encoding
         '-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
         // That filter only works for AAC audio and breaks AC3/EAC3/MP3.
         // If AAC audio from MPEG-TS fails in MP4, use /api/transcode instead.

server/routes/transcode.js

@@ -29,7 +29,7 @@ transcodeSession.startCleanupInterval();
  * Body: { url: string, seekOffset?: number }
  */
 router.post('/session', async (req, res) => {
-    const { url, seekOffset } = req.body;
+    const { url, seekOffset, videoMode, videoCodec } = req.body;
 
     if (!url) {
         return res.status(400).json({ error: 'URL is required' });
@@ -46,7 +46,9 @@ router.post('/session', async (req, res) => {
             seekOffset: seekOffset || 0,
             hwEncoder: settings.hwEncoder || 'software',
             maxResolution: settings.maxResolution || '1080p',
-            quality: settings.quality || 'medium'
+            quality: settings.quality || 'medium',
+            videoMode: videoMode, // 'copy' or 'encode'
+            videoCodec: videoCodec // 'h264', 'hevc', etc.
         });
 
         await session.start();