Distorted incoming audio on ChanSpy and MixMonitor


I’m running (compiled from source) and I’m haunted by a very annoying problem.
On ChanSpy and MixMonitor recordings, on some of the destinations that we’re dialing out, the party we’re calling sounds very distorted.
The local phone is connected to asterisk via SIP (and using alaw), the outgoing trunk is also SIP (using g729).
I must also mention that on Yealink phones we’re using, everything is crystal clear
Tried the following:
-Change the format in which the recordings are made (from Wav to Ogg)
-Changed the recording destination to a tmpfs directory
-Enable/disable transcode_via_sln
-Force a jitter buffer
-Tried various timing modules (dahdi - there is a PRI, timerfd and pthread)
-Changed our SIP clients (the Yealink phones) to g729
As a last resort, moved the g729 transcoding to another machine with two trunks only:
SIP to the VoIP provider and IAX to the previous machine (which is now only handling alaw). Still no improvement.
Must mention that the CPU load is insignificant in both scenarios.
Again, only certain destinations (local landlines) are affected by this problem.
The VoIP provider insists on the fact that they are only using g729.a (so in theory not a VAD problem).

I can provide audio samples for anyone interested.

Thank you for your time.

Also I would like to mention that even when disabling the MixMonitor, the problem will still occur in ChanSpy.
(I know that there was a problem with ChanSpying a MixMonitored channel few versions ago).
I haven’t tried Monitor ,m) but I really don’t think this will solve the problem.

Anyone experiencing similar issues?

Hi nmirceac,

I have the same problem. Were you able to solve the problem?

I’m running 1.8.9

Hi all, same problem here:
Asterisk 13.1.1
CentOS 6.5 x86

If I Chanspy with whisper to an IAX peer from my SIP phone, the IAX receive my voice with a very poor audio quality.
I’m still looking for a solution but until now I’ve found that this bug\problem is unsolved from almost 10 years
comments.gmane.org/gmane.comp.te … ser/151538
nobody have found a possible solution?
Thanks all that can help!