[vlc-devel] [PATCH] Merge VoD module into RTP stream output module

Pierre Ynard linkfanel at yahoo.fr
Sat Oct 30 20:54:23 CEST 2010

> Le samedi 30 octobre 2010 09:00:29 Pierre Ynard, vous avez écrit :
> > > Why do you need to a specific PTS?
> > 
> > The RTSP headers already give the initial RTP timestamps to the
> > client, before the instance and the rtp sout are started. So I need
> > to use a common reference, and I need to pass it somewhere.
> Might as well create a value that can be recomputed from the infos
> that the vod stream already has. The use of mdate() was purely
> arbitrary.

Yeah, I guess the timestamp can be derived from the p_media address
and/or the session identifier. Any security issue with that?

> > We could also implement streaming several payload types in the same
> > RTP session,
> Yes, but that's rarely useful. First, the design of RTP implicitly
> limits this to payload types with equal timestamp frequency. Otherwise
> delay jitter computations and synchronization would go crazy. Second,
> I have to expect many receivers will fail miserably, including current
> VLC.

RFC 3550 §5.2 suggests using different SSRC for each payload type in the
same RTP session to avoid these problems.

Pierre Ynard
"Une âme dans un corps, c'est comme un dessin sur une feuille de papier."

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