AMD & g729 codecs


We’re trying to activate AMD in a call centre that uses g729 codecs.

We have taken the configuration like for like from a working customer setup in the UK who does not have g729 codecs (alaw or gsm is used). Both centres use VoIP, the only other difference is one is in Canada and the other is in the UK.

Every time a call comes through the answer machine detection fails to correctly mark the call. It doesn’t connect any calls through to the agents and it is causing a problem.

Are there any differences with the g729 codecs and AMD on Asterisk? I spoke to somebody who said that it might need to be transcoded for AMD?

On all centres we use Asterisk 1.4.36.

Thanks in advance! :smiley:

G.729’s far more lossy than alaw, so it could be playing some havoc with app_amd. Have you experimented with not using G.729 for this new setup?

Unfortunately, yes. The customers VoIP provider requested from go that they had g729 codecs.

I’ve never had a g729 codec setup with AMD.

I’m stuck. :frowning:

Just to check the obvious, you do have G.729 codecs installed and licensed on Asterisk? You can’t rely on passthrough if you do things like AMD.


Yes, all g729 codecs are fully installed…all 90 of them.

I have managed to get it working with a bit of tweaking of amd.conf.

A lot of people say that Asterisk’s AMD is not that good and it’s better to use Sangoma CPD.