[Asterisk-video] IAX timestamps, presentation vs transmission time Re: [asterisk-dev] Video packetization proposal

[Sergio Garcia Murillo]

General thoughts on video/audio syncronization, presentation vs transmission
times and the like.

Probably most of you are aware, but just to make sure.

On rtp, the video timestamp is the capture time of the frame, and it's
initialized randomly.
So the use of it is just for display the video at the correc rate and the
only way of doing
audio/video syncronization is via rtcp (correlating both ts).

Said that, I've never used rtcp for it. I have always worked at very low
bitrates, so that
means low fps and increased delay (as the frame usually takes some extra
time to be sent if
you don't want your packet exceed the bandwith and get dropped by the
network).
I've always worked on best efford, decode and display as soon as I can. The
results
were quite good as the fps were low.

Greetings
Sergio