g729a and g711/ulaw CPU

I am considering switching my pbx over to using g729a from ulaw. I have found several sites saying that the bandwidth needed is a bit less for g729, but the cpu usage will increase. Is this cpu increase only the case with codec conversions (ulaw to/from g729a)?

My phones support the g729a codec, my sip provider/trunk support g729a natively, and if i install the g729a coded (from digium for example), my pbx server will support g729a. Would this still result in a big cpu hit, or would the increase be much less?


The hit is irrelevant with modern processors.

If you are not transcoding you do not need licenses.

Several things must happen for this to work. You need to install the Asterisk g.729 sound files and make sure that your trunk is g.729.

I think voicemail will still require you to have a few licenses on your system.

Alright. I wasn’t able to get it to work with no licenses on the system. Not really an issue, was just bored.