[Asterisk-Users] g729 versus g711

[Steve Underwood]

Latency doesn't vary much with the codec. Different codecs package 
different amounts of audio per packet, but that is usually a small part 
of the overall latency with VoIP.

If G.711 is used with a reasonable quality PLC algorithm, like the new 
one in *, it beats G.729 hands down in its packet loss tolerance.

snacktime wrote:

>I'm curious which of these codecs is more affected by latency and
>packet loss?  I'm testing both of them out in a scenario where both
>ends of the call have good connectivity, but the distance between them
>is at least 8 hops and some latency is involved.  One end is my * box
>and the other end is teliax/livevoip.  My * box is a 3ghz dell
>poweredge dedicated to * with low call volume and a 100mbps connection
>directly to internap.
>
>So far I seem to get better quality with ulaw.  
>  
>
The high bit rate codec sounds better than the low bit rate one. Now 
there is a surprise. :-) Seriously, it should be like this. Sometimes in 
VoIP systems it isn't. Sometimes people are using the customised built 
in PLC for G.729, and some crude and nasty approach for G.711. In those 
cases G.729 might work better. However, that is just a result of lousy 
implementation.

Regards,
Steve