CODEC modules have file names that look like codec_xxxxx.so, such as codec_alaw.so and codec_ulaw.so. CODECs represent mathematical algorithms for encoding (compressing) and decoding (decompression) media streams. Asterisk uses CODEC modules to both send and recieve media (audio and video). Asterisk also uses CODEC modules to convert (or transcode) media streams between different formats. Modules Provided by Default Asterisk is provided with CODEC modules for the following media types: • ADPCM, 32kbit/s • G.711 A-law, 64kbit/s • G.711 µ-law, 64kbit/s • G.722, 64kbit/s • G.726, 32kbit/s • GSM, 13kbit/s • LPC-10, 2.4kbit/s Other Formats and Modules The Asterisk core provides capability for 16 bit Signed Linear PCM, which is what all of the CODECs are encoding from or decoding to.

There is another CODEC module, codec_resample which allows re-sampling of Signed Linear into different sampling rates 12,16,24,32,44,48,96 or 192 kHz to aid translation. Various other CODEC modules will be built and installed if their dependencies are detected during Asterisk compilation. • If the drivers are detected then codec_dahdi will installed. • If the Speex () development libraries are detected, codec_speex will also be installed. • If the iLBC () development libraries are detected, codec_ilbc will also be installed.

The iLBC or Internet Low Bandwidth Codec was developed by Global IP solutions and was included in Asterisk for many years until it was removed due to possible licensing issues. Google bought GIPS in 2011 and made the codec open source. It uses a 20ms frame rate and a fixed 15. Stock Manager Advance 2 Download there. 2kbit/s bitrate in.

Support for the patent-encumbered G.729A or G. Free Nokia 2690 Game Download Mpbus there. 723.1 CODECs is provided by Digium on a commercial basis through software (G.729A) or hardware (G.729A and G.723.1) products. For more information about purchasing licenses or hardware to use the G.729A or G.723.1 CODECs with Asterisk, please see Digium's website. Support for Polycom's patent-encumbered but free G.722.1 Siren7 and G.722.1C Siren14 CODECs, or for Skype's SILK CODEC, can be enabled in Asterisk by from Digium's website.