Lag root cause: vPipe/aPipe were objectMode PassThrough HWM 128 → the pipe
held up to 128 frames ≈ 4.3s of video before backpressure reached the encoder.
The viewer was watching a 4+ second stale backlog.
Fixes (both faithful to @dank074/discord-video-stream):
1. vPipe/aPipe HWM 2 — at most ~1-2 frames in flight (~66ms @ 30fps), so the
writeFrame() backpressure pauses ffmpeg stdout almost immediately and the
whole chain (encoder → NUT → demuxer → vPipe → BaseMediaStream → WebRTC)
runs at the sender's real pace, exactly like dank's 'resume &&= vPipe.write'.
2. Wire vStream.syncStream = aStream — audio is the master clock; video
sleeps/wakes on ptsDelta like upstream newApi.js. Prevents A/V drift under
variable encoder throughput.
asepharyana
11f2ad5f23