[Live-devel] track synchronization with live555

[Ross Finlayson]

>I know live555 library uses RTCP SR reports to synchronize audio and 
>video streams, but doesn't use the rtp-info header present in the 
>PLAY response.

It does, however, make this header information available for clients 
to use - see "MediaSession.hh".

You're correct, though, that the RTP-Info header information is the 
only way to generate a proper presentation time for RTP packets that 
arrive before the first RTCP SR packet.  The VLC developers (in 
particular, Derk-Jan Hartman) tell me that they are currently 
modifying VLC to use the RTP-Info header information upon 
initialization.  At some point I should probably modify the LIVE555 
"RTSPClient" code to do this automatically, so that each client 
application developer doesn't have to deal with this himself.

Note, though, that not all RTP receivers use RTSP (or SIP) for 
set-up, and so not all will have "RTP-Info" information available. 
These receivers must be prepared to deal with inaccurate presentation 
times prior to the arrival of the first RTCP SR.
-- 

Ross Finlayson
Live Networks, Inc.
http://www.live555.com/