Supporting independent audio and video demuxers in vlc?

Ross Finlayson finlayson at
Thu Sep 5 09:11:59 CEST 2002

As I noted last month, I have been looking at adding RTP & RTSP streaming 
support to "vlc".

While I can easily add a "rtsp" access plugin module (analogous to the 
existing "http" module), I'm not yet sure how to make vlc receive and play 
the incoming RTP streams, once they've been initiated by the RTSP protocol.

The basic problem is that, for most MPEG/RTP sessions, MPEG audio and video 
will *not* be multiplexed together in a single (transport or program) 
stream.  Instead, there will be two separate RTP (datagram) streams - one 
containing audio Elementary Stream data, and another containing video 
Elementary Stream data.

For "mplayer", this worked well, because mplayer supports independent audio 
and video 'demuxers' (with the player code reading from each demuxer 
independently).  My impression of "vlc", however, is that it assumes that 
there's just a single input stream - which is assumed to be a multiplexed 
MPEG Transport or Program Stream.

If this is the case, then how easily could vlc be made to handle 
independent audio and video streams?

One other question: In "access" plugins, what is the purpose of the 
"pf_set_program" and "pf_set_area: functions?


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