Codecs are used to convert an analog voice signal to digitally encoded version. Codecs vary in the sound quality, the bandwidth required, the computational requirements, etc.
Each service, program, phone, gateway, etc typically supports several different codecs, and when talking to each other, negotiate which codec they will use.
As an example, a Cisco ATA-186 supports these codecs:
G.723.1, G.711a, G.711u, G.729a (please note that ATA-186 has x2 FXS ports, there is only one port can run on (G.729) with two simultaneously
active ports, second one will be on G.711a/u)
As an example, a Cisco 7960 supports (Firmware P0S3-06-0-00):
G.711a, G.711u, G.729a
Some codecs require payment of royalities for their use in a product or program. See Codec Patents for more information.
Some tables comparing different codecs:
Each service, program, phone, gateway, etc typically supports several different codecs, and when talking to each other, negotiate which codec they will use.
As an example, a Cisco ATA-186 supports these codecs:
G.723.1, G.711a, G.711u, G.729a (please note that ATA-186 has x2 FXS ports, there is only one port can run on (G.729) with two simultaneously
active ports, second one will be on G.711a/u)
As an example, a Cisco 7960 supports (Firmware P0S3-06-0-00):
G.711a, G.711u, G.729a
Some codecs require payment of royalities for their use in a product or program. See Codec Patents for more information.
- AMR Codec
- BroadVoice Codec 16Kbps narrowband, and 32Kbps wideband
- DoD CELP - 4.8 Kbps
- GIPS Family - 13.3 Kbps and up
- GSM - 13 Kbps (full rate), 20ms frame size
- iLBC - 15Kbps,20ms frame size: 13.3 Kbps, 30ms frame size
- ITU G.711 - 64 Kbps, sample-based Comes in two flavors: A-law and mu-law
- ITU G.722 - 48/56/64 Kbps ADPCM 7Khz audio bandwidth
- ITU G.722.1 - 24/32 Kbps 7Khz audio bandwidth (based on Polycom's SIREN codec)
- ITU G.722.1C - 32 Kbps, a Polycom extension, 14Khz audio bandwidth
- ITU G.722.2 - 6.6Kbps to 23.85Kbps. Also known as AMR-WB. CELP 7Khz audio bandwidth
- ITU G.723.1 - 5.3/6.3 Kbps, 30ms frame size
- ITU G.726 - 16/24/32/40 Kbps
- ITU G.728 - 16 Kbps
- ITU G.729 - 8 Kbps, 10ms frame size
- LPC10 - 2.5 Kbps
- Speex - 2.15 to 44.2 Kbps
Some tables comparing different codecs:
