[Live-devel] Is it possible to enable RFC 6051 extended headers for rapid stream synchronization

[Ross Finlayson]

> On Jan 19, 2021, at 2:20 AM, David Gessel <gessel at blackrosetech.com> wrote:
> 
> Dear Live555 list,
> 
> I am trying to sync multiple mobotix IP cameras, which use Live555 as the RTSP server.  I'm having a little trouble getting multiple streams to sync at all

Before answering the rest of your question, we should step back and ask why you - as a RTSP client - are having trouble getting audio/video to sync at all.  First, read
	http://live555.com/liveMedia/faq.html#separate-rtp-streams
If the RTSP server really is using our implementation, then audio/video synchronization (using standard RFC 3550 RTP/RTCP) should work OK.  Try running VLC <http://www.videolan.org/vlc/> (which uses the LIVE555 RTSP client implementation) as your RTSP client.  Do you get proper A/V synchronization using this client (perhaps after the first second or so, until the first RTCP “SR” packet arrives)?

If not, then the problem is your RTSP server (the ‘Mobitex’ IP camera).  Please make sure that they are using the latest version of the LIVE555 software.  (Note that, under the conditions of the LGPL, they are required to provide a way for you to upgrade the LIVE555 software.)

If, however, regular RFC 3550 RTP/RTCP audio/video synchronization is working OK, but - for some reason - you want the faster synchronization mechanism described by RFC 6051, then let us know, and we can discuss this.  But first we need to make sure that regular RFC 3550 RTP/RTCP synchronization is working OK for you.


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