[Asterisk-Users] Re: Asterisk 1.2.4 IAX2 New Jitterbuffer Tuning

[Rich Adamson]

> >> After 2 weeks of messing around with every conceivable IAX2 and
> >> jitterbuffer configuration, I switched to SIP yesterday.  Complaints
> >> went from 10-20 per day to ZERO.  Literally overnight.
> > 
> > I wonder if this is an ILBC frame size issue of some sort?  Seems odd.
> 
> I've got to add my name to the list here.  We're just using GSM over our IAX
> links, and our jitterbuffer values look like this:
> 
> maxjitterbuffer=1000
> resyncthreshold=1000
> maxjitterinterps=10
> 
> For the most part the new jitterbuffer actually yields much better quality
> than the old jitterbuffer, but when the resyncs happen, it's like the call
> has a lot of trouble getting get back on track.  It flounders for quite a
> while, with badly broken audio, sometimes up to 20 seconds before coming
> back.  I've tried hanging up as soon as event starts happening and then
> immediately calling the same number, and the channel comes back with crystal
> clarity.  So it seems to me like there is something askew with the resync.

If memory serves correctly, I believe I remember Mark applying a fix to
the iax jitterbuffer and that fix had something to do with a counter
rollover or something like that. That fix happened in the last week or
so.

I'm not sure if that would have been included in v1.2.4 or not, but might
be worth a little research.

I also opened a bug a month or two ago involving ilbc and iax, and someone
else confirmed it was a bug. Don't have the bug number handy, but the
problem related to a combination of iax trunking, jitterbuffer and ilbc.
Disabling one of those consistently bypassed the problem.