H.264 RTSP Absolute TIMESTAMP

timestamp h.264 rtsp rtp
Grifo picture Grifo · May 27, 2011 · Viewed 10.1k times · Source

Is it possible to read an absolute timestamp from an H.264 stream sent trough RTSP from an Axis camera?

It will be necessary to know when the frame has been taken by the camera.

Thanks Andrea

Answer

jenseb picture jenseb · May 28, 2011

as Ralf already said - the RTP timestamps are relative to a random clock - they are only useful for computing the difference between two frames (or RTP-packets in general). For synchronizing these relative values to a wall clock you can use the RTCP sender - just have a look on the links Ralf provided.

For Axis-products using H.264 this works pretty good. In case you're also using MPEG4, the Axis firmware is buggy and the absolute timestamps in RTCP SR are not reliable - in this case you have to synchronize the relative RTP timestamps to your clients wall clock.

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