[asterisk-dev] Echo canceller not working

[Diego Iastrubni]

Hi all,


I am trying to solve the issue of echo canceler issues on Rapid. For 
some reason, we can hear a terrible echo on x100p, as well as our own 
Astribank FXO. Here is what I tried:


I tested it on asterisk 1.0.10 with Zaptel 1.0.10, the default echo 
canceler (KB1). Still I headred echo.

I tested it on asterisk 1.0.10 with Zaptel 1.2.5, with all the echo 
cancellers, one by one. Still I heared echo.


Then, I tested asterisk 1.2.7.1 with zaptel 1.2.5, with all echo 
cancelers available, even MG2 with the aggressive option set on. I 
verified that on the load of zaptel the correct echo canceler is set up. 
The echo canceler reported on the modules loading is correct, and still 
I head echo on all echo cancelers combinations.


On all those tests I see on asterisk, that the specific channel has the 
echo canceler on.


Next step, was recompilig asterisk/chan_zap, with these modifications:

- #define READ_SIZE 160
+ #define READ_SIZE 16

And add this line in zapata.conf:
jitterbuffers=40 

Still no success. (someone told me this would help).

Next step was knowing for sure that I am using a clean source. I recompiled chan_zap from the stock sources, and installed it. I also added also some debug prints to see that chan_zap is trying to ask zaptel to enable the echo canceler. It seems that chan_zap is trying to call the ioctl. (what an ugly code BTW, it gives a new meaning to spaggety code).

Then, I started hacking inside zaptel and print debug information to see that at least the ioctl is working. It is. 

Next was adding some printk to echo_can_create() and echo_can_free() to see that at least the correct functions are beeing called. Well, they are. It seems that on the surface, we are calling the correct functions, and evenything "should" be working. It's still not working, and the echo canceler code still is not working.

What should be my next step? Since I heard all the cool guys are now on Europe, they should be up around now... If any of those gurus are on the irc, I will be glad to get some help on #asterisk or #asterisk-dev as "cuco". Fell free to poke me. If not, I am still happy to get more information via plain old email.

--
diego