[Asterisk-Dev] More IAX tests with different codecs

[John Todd]

More IAX tests.

1) IAX with GSM
   Works fine, sounds fine.  No dropouts, mild artifacts (but nothing 
that is a "problem")

2) IAX with G711
   Works fine, sounds great.  No dropouts, no artifacts, very very 
faint echo (1/4 second?) - not an issue, but if you crank the volume 
up all the way to 11, you can hear it.

3) IAX2 with GSM
   2-3 second drops often, mild artifacts

4) IAX2 with G711
   2-3 second drops often, mild artifacts


During my calls last night, I was unable to reproduce the total audio 
leg drops, but others have said that it happens frequently with IAX2, 
and I have had it happen often as well.  The network between the two 
ends was unsaturated, and throughput tests were >200kbps with no 
packet loss.

Tests were done with VAD turned on, and turned off on each SIP end 
station.  That didn't seem to make much of a difference, but it was 
interesting to watch bandwidth drop to zero when nobody was talking. 
We did not experiment with jitterbuffer=  - that will be tonight.

JT