g729 licensing question


I am currently looking at using g729 and have a question. I notice that asterisk requires a per channel license.

If I am only passing through g729 do I really need a license?
If I upload my ivr recordings in g729 format, and the user browses my IVR ( and the devices codec is g729) do I really need a license ?
Is it possible to tell asterisk to make a recording in g729 format instead of trying to convert it to a wav? If I do this, do I really need a license?
Is it safe to assume that Linksys, Grandstream and Snom have all paid the appropriate licensing fees for their devices?



To avoid the need for a G.729 licence you need to remove the Asterisk server from the media stream path and use the same codec (i.e. G.729) end-to-end. This means that the same signalling protocol must be used between the two endpoints and they must have direct IP reachability. Using SIP you would configure canreinvite=yes, which means that the VoIP endpoints would communicate directly rather than through the Asterisk server (see voip-info.org/wiki-Asterisk+sip+canreinvite).

However, there are some disadvantages to removing the Asterisk server from the path, such as losing the ability to record calls, use IVR, and leave voicemails. In your case if you want to use Asterisk to make a recording in G.729 then you will definitely need a licence. However, you only need 1 licence per active call/recording (i.e. not per extension or trunk).

$10 USD per channel is pretty reasonable. However, as an alternative to the Digium provided licences, you can also purchase licences from here asterisk.hosting.lv, however, you may need to pay royalty fees if there is a patent covering your country and the Open Source version is not recommended for business use.


That actually isn’t totally true. Asterisk can stay in the media path between two G.729 devices using the same signalling. It will do pass-thru without requiring a license. The only time asterisk needs a license is when it needs to transcode to/from g.729.

Just make sure your asterisk system isn’t set to transcode all calls to slinear, which is a setting in asterisk.conf

g2010, thank you for the information, I wasn’t aware that this is the case. Having looked into it further it appears that you don’t need a licence for voice mails either if you disable silence detection, although they can’t be accessed via PSTN trunks because it would require transcoding. I guess you could also record IVR prompts using g.729, but again the prompts couldn’t be accessed via PSTN trunks. Do you know if you need a licence for call monitoring/recording if you are using g.729?