Using G.729 with Asterisk or other PBX requires a license per channel unless it is used in a way that does not convert the G.729 encoded data to another format; for example : Asterisk G.729 pass-thru mode. A GPLv2 compliant license can be purchased from a company that re-sells G.729 licenses such as:
Digium Synapse Global Corporation - $9.50/ea
Digium Licenses When upgrading the number of licenses, Digium will have to merge the old licences with the new & provide a new license file. Reboot the server to be sure that the license is seen correctly.
Warning In a recent email I received from Digium technical support I was told: "A hostid, is based on the sum of ALL the hardware in the machine, more specifically you are purchasing a license to use G729 on a single hardware set. You are allowed to install on a testing server as well, or if you need save the second hostid incase of needed hardware changes."
While they did allow me one additional change, be aware that if you are using them in a server where ANY hardware might change these aren't much of a valid option. After the one additional change they refused a second, even though in the latter case NO hardware changed.
Study or experiment with G.729 for free Under patent law, it is a legitimate use to study or experiment with a patented technology without paying for a patent license. You only have to pay royalty fees if you sell a product based on the technology or use the technology in products internally (this includes using the codec in a commercial setting, even if you aren't selling your platform, but only a service). Do not depend on this as legal advice, consult your own legal advisor.
Opensource implementation An opensource implementation of G.729 codec can be found at http://www.readytechnology.co.uk/open/ipp-codecs-g729-g723.1/. It is a wrapper around Intel Integrated Performance Primitives. Please note: You might still have to pay royalty fees to the G.729 patent holders for using their algorithm and to Intel for using their libraries!
Binaries can be found at http://asterisk.hosting.lv/
Warning Please see Marks response on the user list (dated 25 Sep 2004) regarding use of non GPL-compliant G.729 codec from other sources. In short, this violates the GPL license and jeopardizes the asterisk project, specifically because the advocacy of its use may be seen by patent lawyers as contributory infringement. If you do choose to use this module, please be aware of the restrictions on using it without purchasing licenses, and do not advocate its use on any Digium-sponsored mailing lists (again, this could be seen as contributory infringement, if Digium resources are used to encourage its use).
There is some disagreement about whether this truly does violate the GPL. The FSF, in particular, has rendered the legal opinion that it does not violate the GPL even if the modules are not GPL compatible. The GPL violation would occur only if GPL and non-GPL compliant code is distributed together or if the module links to GPL code (use ldd to verify what it links to) or is derived from GPL code (see copyright.gov for US copyright law on derivative works; look to your own countries' laws potentially in addition to the US laws since Digium is in the US). There is a page on this wiki that talks about asterisk GPL compliance and another that talks about how to make non GPL modules for asterisk legally.
GPL Myth Note: the GPL is a distribution license, not a use license. If you downloaded Asterisk from someone else and are using it, the person you downloaded Asterisk from must comply with the GPL. If you combine a static G.729 binary (non-GPL compatible licensed) with GPL software, YOU DO NOT VIOLATE THE GPL UNTIL YOU DISTRIBUTE THE COMBINATION. You ARE, however, allowed to use it yourself. Acceptance of the GPL is NOT required to download and use Asterisk, either by itself or in combination with the above G.729 implementation. Therefore, if you're not planning on giving copies of Asterisk away to others, the above GPL violation statement doesn't apply to you. For more information, please see the GPL FAQ.