fix(audio): use_wallclock_as_timestamps on both raw FIFOs to align A/V by arrival time (no deadlock, replaces barrier)

services/capture/src/capture-manager.js

@@ -613,11 +613,22 @@ class CaptureManager {
 
       return {
         inputArgs: [
+          // Both raw FIFOs are timestampless. ffmpeg opens input 0 (video) and
+          // input 1 (audio) at slightly different moments, so PTS-zeroing each
+          // stream's first byte would bake in a fixed A/V offset. Stamping each
+          // input by wall-clock ARRIVAL time aligns them by real time regardless
+          // of FIFO open order — the robust fix for the A/V start offset.
+          // Large thread_queue_size avoids "thread message queue blocking" on
+          // the high-bitrate raw video FIFO.
+          '-use_wallclock_as_timestamps', '1',
+          '-thread_queue_size', '512',
           '-f', 'rawvideo',
           '-pix_fmt',    'uyvy422',
           '-video_size', dcSize,
           '-framerate',  dcFps,
           '-i', videoFifo,
+          '-use_wallclock_as_timestamps', '1',
+          '-thread_queue_size', '512',
           '-f', 's16le',
           '-ar', '48000',
           '-ac', '2',