[Asterisk-video] Video Conferencing Solutions

[Neil Stratford]

Hi,

 >> My guess would be that your video
>> streams don't have key frames at short enough intervals, so you're
>> basically getting p-frames from the new stream, while your endpoint
>> still thinks it is decoding the old stream.
> 
> Your guess sounds like it might be correct, when switching with DTMF I
> often see the new stream "blend" into the old one before it completely
> switches over.  Any suggestions on how to fix this?

The 'correct' solution to this is to ask the source video stream for a 
new key frame when you need it. There are unfortunately several 
mechanisms for doing this (SIP INFO, RTCP etc), and in my experience 
different vendors expect different mechanisms. app_conference attemtps 
this request by sending an Asterisk control frame of 
AST_CONTROL_VIDUPDATE, which *should* result in a key frame request 
being generated, but probably not in the form your phone needs.

My suggestion would be to experiment with VIDUPDATE handling in 
chan_sip, but it's likely to involve some serious hacking.

Neil
-- 
Neil Stratford - http://www.vipadia.com/ - sip:call at vipadia.com
Vipadia Limited :: VoIP Research and Development