[EMAIL PROTECTED] wrote:
On Tue, 3 Aug 2004, Steve Underwood wrote:
Eh? G.729 has no particular features to allow more effective packet loss
concealment. iLBC has, but at the cost of a substantially higher bit
rate. In fact G.711 is a little ahead of G.729 in the regard, since
packets are completely independant. The smoothing in G.729 means you
need the previous packet to decode the current one properly.
For IAX2, at least, Asterisk oes not use the lost-packet-concealment of
any codec. This is because the incoming frames "clock" Asterisk. For
iLBC's lost packet concealment to work, Asterisk would have to start
calling the decoder with a NULL at the point when the missing packet shold
have arrived.
This certainly explains why we get terrible audio at 10% packet loss
between Asterisk servers between 2 end points using iLBC, but if we use
2 SPA2000s using G.729 to commincate directly with each other (and
having the same 10% packet loss), they sound pretty good. We had been
trying to figure why iLBCs loss concealment wasn't helping much. I was
never able to explain this until now:)
Thanks.
--
Andres
Network Admin
http://www.telesip.net
_______________________________________________
Asterisk-Users mailing list
[EMAIL PROTECTED]
http://lists.digium.com/mailman/listinfo/asterisk-users
To UNSUBSCRIBE or update options visit:
http://lists.digium.com/mailman/listinfo/asterisk-users
