CodecPro G.729 Codec
ITU-T standard codec

Based on the Code Excited Linear Prediction (CELP) coding model, the G.729 codec delivers toll-quality speech, similar in quality to 32-kbps ADPCM but at one-quarter the bitrate. With the low rate of 8 kbps, G.729 is the lowest-bitrate 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 VoIP, where quality, delay and bandwidth are all important, benefit substantially from this codec.

Annex A (G.729A) has approximately half the complexity of G.729. G.729 and G.729A are totally interoperable.

Annex B (G.729B) is a discontinuous transmission (DTX) functionality that interrupts the transmission during silence for VoIP communication. This functionality can be merged with G.729A to form G.729AB.

Annex D (G.729D) is a 6.4-kbps CS-ACELP speech coding algorithm.

Annex E (G.729E) is an 11.8-kbps CS-ACELP speech coding algorithm.

Annexes F, G, H and I are combinations respectively of annexes B&D, B&E, D&E and B&D&E.


The memory and CPU details are generic Standard specifications, for more detail and information about CodecPro's G.729 optimisation, please contact us at

Bandwidth 200-3400 Hz
Standardized ITU-T 1995
Technology ACELP
Bit rate 8 kbps
Delay (msec) 15
Frame size (msec) 10
Lookahead (msec) 5
Quality Narrowband / PSTN
Complexity (MIPS) 20
ROM (bytes) 50K
RAM (bytes) 4K + 3K/ch

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Phone: +1.514.916.3663