H.264 RTSP Absolute TIMESTAMP

Question

Can an absolute timestamp be read from an RTSP stream transmitted over an H.264 stream from an Axis camera?

You need to know when the shot was taken by the camera.

Thanks Andrea

Answer 1

as Ralf already said, “RTP timestamps refer to random clocks,” they are only useful for calculating the difference between two frames (or RTP packets in general). You can use the RTCP sender to synchronize these relative values ​​with the wall clock - just look at the links provided by Ralf.

For Axis products using H.264, this works very well. If you also use MPEG4, the Axis firmware does not work, and the absolute timestamps in RTCP SR are unreliable - in this case you need to synchronize the relative RTP timestamps with your clock on the wall.

Answer 2

Timestamps are contained in the RTP stream. RTSP is a protocol that can be used to start / manage an RTP session. I assume RTP is used, and you can see the RTP header here .