[Asterisk-Users] Re: Why Asterisk can't cope with silence suppression?

[Rich Adamson]

> >> >>Essentially its because * has been architected to send an rtp packet 
> > "after" receiving a packet. If * never "see's" and >>>incoming rtp 
> > packet, then it won't send an rtp packet (which usually contains some 
> > amount of audio). Thus choppy audio >>>in one direction.
> > 
> > So why can’t * just play comfort noise when it doesn’t see any rtp 
> > packets in a particular bearer channel?   Unless I am missing something 
> > fundamental this doesn’t seem to be a huge architectural change.  I’d 
> > have to agree that a lack of proper vad support is a major shortcoming.
> 
> It's more than that, from what I know a *missing* RTP packet could be 
> 'silence' (vad) or it could be 'network related' (jitter).  * not seeing 
> a packet doesn't always mean it was vad, it might mean your network had 
> a split second (subsecond) hiccup that caused the packet to disappear - 
> both 'look the same' to *.  This is why someone had already mentioned 
> the idea that the new jitter-buffer might handle this better/correctly.

Personal opinion (and everyone's got one) is that vad does not produce the
savings that one might expect. People are use to constantly talking (in
many cases full-duplex-style), room background noise, dog barking, etc, 
etc, which reducees the impact. Vad may have some small value for 
residential voip users where their bandwidth is a little on the too-
small side, but asterisk was not designed with the intent of putting a
pbx in every home.