[asterisk-dev] iLBC packet loss concealment (was: code-cleanup concerns)

[Matt Ranney]

On Apr 15, 2006, at 11:18 PM, John Todd wrote:

> Skype has good quality because of several factors: they are  
> primarily soft-client based, so they can use better-than-telephony  
> sound quality on both sides of the connection to start with, and  
> secondly because they are using a patent-encumbered version of iLBC  
> from Global IP Sound (GIPS) which I assume has both better PLC as  
> well as better compression characteristics.  I'll put my $.02  
> towards Asterisk supporting better codecs at higher bitrates  
> (Speex, notably, has the ability to do much better than "MOS 4", or  
> "toll-quality" sound - stereo, higher bitrates, etc.)  since this  
> is next-generation telephony system implementation, not last- 
> generation telephony system design.

My users tell me that Skype sounds better than asterisk even when  
going to the PSTN, but I think this might be because the headsets  
they are using just sound better than their Cisco 7940 handsets.

They also tell me that they get far fewer dropouts and never any echo  
when using Skype compared to asterisk over the same WAN link.

BTW, my setup is:

Cisco 7940 -- SIP/ulaw -- asterisk -- IAX2/g.729 -- asterisk --  
Digium PRI card