G.729 and G.723.1 codecs for Asterisk open source PBX

Primary website / Google group

Asterisk 1.4, 1.6, 1.8, 10, 11, 12, and 13 are supported.

To compile the codecs it is recommended to install Intel IPP libraries for better performance. Alternatively, you need to download and install Bcg729 - a slightly slower implementation written in portable C99. Only G.729 will be available in that case.

The codecs are tested against Bcg729 1.0.0, IPP 5.3, 6.0, 6.1, 7.0, 7.1, 8.0, 8.1. Use IPP 5.3 for Pentium3, and 6.0+ for Atom CPU. AMD processors works with IPP without problems.

Use ./autogen.sh to generate GNU Autoconf files, then ./configure. Check available options with ./configure --help. Specify --prefix in case Asterisk is installed in non-standard location.

G.723.1 send rate is configured in Asterisk codecs.conf file:

; 6.3kbps stream, default
; 5.3kbps

This option is for outgoing voice stream only. It does not affect incoming stream that should be decoded automatically whatever the bit-rate is.

There are also two Asterisk CLI commands g723 debug and g729 debug to print statistics about received frames sizes. This can aid in debugging audio problems. You need to bump Asterisk verbosity level to 3 to see the numbers.

astconv is audio format conversion utility similar to Asterisk file convert command. Build it with supplied build-astconv.sh script against Asterisk 1.8 or later. astconv uses codec_*.so modules directly to perform the conversion. You need codec module that was compiled against same Asterisk version the astconv was built against.

The translation result could be used to: (a) confirm the codec is working properly; (b) prepare voice-mail prompts, for example:

./astconv ./codec_g729.so -e 160 file.slin file.g729
./astconv ./codec_g729.so -d 10  file.g729 file.slin
./astconv ./codec_g723.so -e 480 file.slin file.g723
./astconv ./codec_g723.so -d 24  file.g723 file.slin

file.slin is signed linear 16-bin 8kHz mono audio, you can play it with alsa-utils:

aplay -f S16_LE file.slin

and convert between other formats with SOX:

sox input.wav -e signed-integer -b 16 -c 1 -r 8k -t raw output.slin
sox -t raw -e signed-integer -b 16 -c 1 -r 8k input.slin output.wav


  • codec_g72x.c - GPLv3, code is based on code by Daniel Pocock at http://www.readytechnology.co.uk/open/ipp-codecs/ and various Asterisk bundled codecs;
  • astconv.c, build-astconv.sh - GPLv3;
  • autoconf files initially contributed by Michael.Kromer at computergmbh dot de;
  • g723_slin_ex.h, g729_slin_ex.h, slin_g72x_ex.h - sample speech data;
  • ipp/ files are copied from IPP samples, IPP license apply.

Before reporting problem with the codecs, please read the website and make sure you know what you're doing - compiling the codecs is not a novice task. Asking Asterisk G.729 Google group first is also good idea.