[Asterisk-Dev] Echo with iaxcomm

[Steve Kann]

On Mar 25, 2004, at 5:40 PM, Duane wrote:

> sudhir1 at adelphia.net wrote:
>> I tried all combination of echo cancellation, noise reduction and 
>> gain control, but the terrible echo wont go away. It is same with SIP 
>> phone. The problem is only when iaxcomm is one leg of the call.
>
> I think I had the same issue, untick the echo cancellation option...


The echo cancellation in iaxclient [behind iaxcomm, iaxphone, and diax] 
is currently broken.  It is based on the echo cancellation in libspeex, 
written by Jean-Marc Valin.  The "engine" is there, and works pretty 
good, but it doesn't have proper near-end voice detection, and 
therefore it's "learning" mode is always on, and gets confused when 
there's near end signal.

So far, I haven't found a working solution for echo cancellation in 
iaxclient, although I'd like to see it in there.  Jean-Marc's solution 
seems the most promising though, because it scales better to the 
[possibly very long] echo tails that you're likely to see with acoustic 
echo in a softphone.

So, for now, I'd say that iaxclient users shouldn't expect echo 
cancellation to work.  If someone is interested in trying to implement 
echo cancellation, however, there would be lots of grateful people out 
there who want to use iaxclients with either open speakers, or with 
lousy soundcards which always produce echo internally.


-SteveK