Sync video from multiple IP cameras


When live streaming the same hockey game with two RTSP H.264 cameras, can the two video streams play in sync?

No wall clock in this setup; both cameras are standalone.

I think Yes, in theory.

We expect the clocks on the two cameras accurate enough. (frequent NTP helps)

The two RTCP servers on the cameras map the RTP time stamps to UTC time.

PTS can be calculated from RTP time stamp.

By RTP and RTCP, we have the PTS in UTC, and therefore, sync the two videos.

Problem: packages from RTCP may not inaccurate/missing in reality.

References:

1: https://stackoverflow.com/questions/2439096/h264-rtp-timestamp

[“Non interleaved”, in which, you must set the RTP timestamp to the PTS + offset]

2: https://groups.google.com/forum/#!msg/discuss-webrtc/npLmOesI8A4/oL2p_HbhAgAJ

[synchronization between two RTP streams using RTCP SR]

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