[Asterisk-Users] iaxtel and jitterbuffer

[Andrew Kohlsmith]

On Sunday 29 August 2004 15:52, steve at daviesfam.org wrote:
> The jitter buffer makes all its decisions about dejittering based on the
> timestamps of incoming frames.  There a fundamental expectation that the
> sending side is correctly stamping each frame - 20msec, 40msec etc etc.

Right, this makes sense.  :-)

> The problem is that the sending side doesn't always do that.  Sometimes
> for one reason or another the stamps "jump".  The receiver has no way of
> telling that the sender mangled the timestamps, and assumes that the
> packets with the new stamps have been delayed, or arrived early, or
> whatever.  Either way, the jitter buffer does its thing and unknowingly
> makes things worse.
>
> Unfortunately, this is why you can still be better off without it - but
> the problem really needs to be fixed by fixing the timestamp generation on
> the sender.

Hmm...  I think next CVS update I'm gonna add a bit of code in chan_iax2 that 
tries to verify that timestamps aren't getting sent incorrectly.  Fun fun 
fun.  :-)

-A.