[Speex-dev] jitter buffer

[Jean-Marc Valin]

> i am using speex in a voip application that has to work on gprs 
> connection. the gprs gives just 9.6 kpbs up. hence, i have an upper limit 
> of 6kpbs on the codec and not more than 5 udp packets per sec. that means, 
> putting in 10 speex frames in every rtp packet.
> 
> i need to jitter compensate for about 50 msec, but that necessarily means 
> holding back 10 frames in the buffer before the next packet arrives. oth, 
> the desktop version will have to dynamically track the settle on rtp 
> packet size by retraining itself with the incoming stream.

>From what you tell me here. You probably want a custom jitter buffer.
The reason is that you want to have a control on times much shorter than
a packet will be. 

> 1) how can i use the VAD at an application level? i would like to make my 
> voip application send packets only when the user speaks and at that point 
> i would like to cut off my playback to avoid echo (voice operated 
> transmit/receive changeover).

Have a look at the VAD included in the 1.1.x preprocessor. (sorry, not
documented yet, though).

> 2) can i control the echo delay ?

What??

	Jean-Marc