[vlc-devel] Problems with synchronizing video and audio using RTP (live555)

Jami Pekkanen jami at floobs.com
Thu Jun 18 08:48:20 CEST 2009

On Wed, 2009-06-17 at 22:28 -0700, Ross Finlayson wrote:
> >I have a setup with a homebrew RTP client
> I think you mean *server*

Well sort of. But VLC is waiting for a connection as "server" and the
"client" starts sending data to it. There's no proper RTSP used
currently, so in the protocol's (RTP/RTCP) point of view there really
isn't a server as such. Perhaps it's clearer to just speak about sending
and receiving ends.

> The problem is with your server, not the client (VLC).  Your server 
> is not implementing RTCP correctly (for both the audio and video 
> streams).

I've inspected the RTCP SR data (only thing sent currently) and it seems
that it is fine. Identical (except for timestamp resolution) RTCP for
the video stream is working which would suggest that the problem is in
timing the AMR buffers in VLC/live555. Also the behavior without RTCP
seems quite odd.

> If your server was built using the "LIVE555 Streaming Media" 
> libraries, then you can try using the "live-devel at lists.live555.com" 
> mailing list to help figure out what's wrong with it.  (But if you 
> didn't use the LIVE555 libraries to build your server, then you're 
> going to have to find help somewhere else.)

I'm using VLC for the receiving end and suspecting that the problem is
in it and/or liveMedia and/or their integration, so I thought asking
here was appropriate.

- Jami Pekkanen

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