| Although we are able to support multiple codecs, our route selection has been optimized for the G.729 codec. If you set this as your primary choice codec, you will get the best quality and ASR possible.
Based on the renowned Code Excited Linear Prediction (CELP) coding model, the G.729 speech compression standard delivers toll-quality speech, similar in quality to 32-kbps ADPCM but at one-quarter the bit rate. With the low rate of 8 kbps, G.729 is the lowest bit rate ITU-T standard with toll quality, offering opportunities for significant increases in bandwidth utilization in existing telephony and wireless applications. G.729 operates on 10-ms frames, allowing moderate transmission delays, so applications such as teleconferencing or visual telephony, where quality, delay and bandwidth are all important, will benefit substantially from this codec |
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There are three variants to the G.729 codec:
- G.729A - The G.729 Annex A: DSVD (Digital Simultaneous Voice and Data) – is a low-complexity version of the G.729 standard. G.729 Annex A offers the best complexity/quality ratio in the industry.
- G.729B – The G.729 Annex B adds VAD/CNG/DTX (Voice Activity Detection/Comfort Noise Generator/Discontinuous Transmission)and acts to define the VAD/DTX/CNG features for G.729 and G.729A.
- G.729E - G.729 Annex E operates at a bit rate of 11.8 kbps using CS-ACELP (Conjugate-Structure Algebraic Code Excited Linear Prediction)
