[Iaxclient-devel] some iaxclient additions.

[Steve K. <st...@st...>]

First, I forget if I posted this or not, but the audio quality issues in
the first release I made last friday have been resolved.  The current
code has pretty good audio quality.

Second, IAX2 support has been added to iaxclient; it's a compile-time
option (set in lib/Makefile), and there are currently a few problems
with it (it works, but only due to some ugly hacks; the main problem is
that the call never gets into the "answered" state; I think this is a
protocol parsing problem, but I'm not sure :)

Third, I've added some DSP functionality to iaxclient and testcall:

1) Audio level support:  via a callback mechanism, a client (like
testcall), can request audio volume level updates, and in a GUI client,
they'd use this for "volume meters".  Both input and output audio
volumes are calculated and passed back.

2) Dynamic range compression:  This needs some tuning, but should help a
bit in keeping good volume levels when people are close to/far from a
microphone, and/or don't have their soundcard mic settings set up just
right.  

3) Silence detection/suppression:  You can set a threshold (in DB, 0 is
full volume, -35 or -40 is a good threshold), below which iaxclient
won't send any audio to the remote side.  Asterisk seems OK with this,
although it doesn't add comfort noise (so, I guess the remote caller
will be "uncomfortable" with this turned on :)).  

These are all implemented via the "compand" effect, from sox, which has
been ported to run inside iaxclient and outside of SOX.

-SteveK



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