Live stream freeze when enabling liveSync with RTSP → MPEG-TS (FFmpeg)

[Forlk4]

Hi, thank you for your great work on mpegts.js.

I’m currently integrating RTSP streaming that is converted to MPEG-TS using FFmpeg. The stream works normally when liveSync is disabled, but once I enable liveSync and related latency-control options, the playback becomes stuck/frozen after running for a short period. Below are the details:

✔️ Working Configuration (no freeze)

{
  "enableWorker": true,
  "enableStashBuffer": true,
  "stashInitialSize": 131072,

  "isLive": true,
  "liveSync": false,
  "liveSyncMaxLatency": 0,
  "liveSyncTargetLatency": 0,
  "liveSyncPlaybackRate": 1,
  "liveBufferLatencyChasing": false,

  "deferLoadAfterSourceOpen": true,
  "lazyLoad": true,

  "autoCleanupSourceBuffer": false,
  "autoCleanupMaxBackwardDuration": 3,
  "autoCleanupMinBackwardDuration": 1,
  "fixAudioTimestampGap": false
}

❌ Problematic Configuration (stream stuck)

{
  "enableWorker": true,
  "enableStashBuffer": false,
  "stashInitialSize": 65536,

  "isLive": true,
  "lazyLoad": false,

  "liveBufferLatencyChasing": true,
  "liveBufferLatencyMaxLatency": 1.4,
  "liveBufferLatencyMinRemain": 0.4,

  "liveSync": true,
  "liveSyncMaxLatency": 1.5,
  "liveSyncTargetLatency": 1.0,
  "liveSyncPlaybackRate": 1.05,

  "deferLoadAfterSourceOpen": false,
  "autoCleanupSourceBuffer": true,
  "autoCleanupMaxBackwardDuration": 3,
  "autoCleanupMinBackwardDuration": 2,
  "fixAudioTimestampGap": true
}

Behavior

• When liveSync is enabled, the stream freezes or stops updating.
• The FFmpeg server performs a reinitialization/recognition every ~30 seconds, which may be related.
• mpegts.js seems unable to recover playback after FFmpeg’s periodic refresh, while the same stream works fine when liveSync is disabled.

Additional Information

• FFmpeg is outputting MPEG-TS over HTTP.
• Browser: Chromium
• OS: Linux
• mpegts.js version: v1.8.0

Question

Is this expected behavior when combining liveSync with an RTSP→TS transcoded stream, or is there a recommended configuration for handling periodic FFmpeg refresh events? Any guidance would be greatly appreciated.

Thank you in advance!