G.729 Annex D is a low bit-rate variant of the G.729 speech codec. G.729 Annex D encodes a 10ms (80 sample) frame into 64 bits, while G.729 (and G.729 Annex A) encodes a frame into 80 bits.
- Mobile, VoIP and Voice Conferencing Applications
- Real-time multi-channel implementation
- Multi-tasking environment compatible
- Optimized for DSPs, RiSC, CISC processors
- DTX functionality, Silence Injection, Comfort Noise Generation (Annex F)
- ITU-T G.729 Annex D and Annex F compliant
- Full and half duplex modes of operation
G.729 Annex D does have a lower bit rate than the main body G.729. G.729 Annex D is able to achieve a lower bit rate by using a sparser ACELP codebook, further quantization on the codebook gains and pitch delay. The tradeoff for this lower bit rate is lower result speech quality, but is still higher quality than many narrowband codecs, such as GSM-HR. This allows a system integrator to select between G.729 or G.729 Annex D based on network conditions.
Configurations
- DAA interface using linear codec at 8.0 kHz sample rate
- Direct interface to 8.0 kHz PCM data stream (A-law or μ-law)
- Common compressed speech frame stream interface to support systems with multiple speech coders
- Dynamic speech coders selection if multiple speech codecs available
- Can be integrated with Acoustic Echo Canceller, G.168 Line Echo Canceller and Tone Detection/Regeneration modules
- Multiple ports can be executed on a single DSP
- Available with VoIP stack
VOCAL’s G.729 Annex D voice compression algorithm is optimized for performance on leading DSPs and RISC/CISC processors from TI, ADI, AMD, ARM, Intel and other vendors. VOCAL offers the G.729 codec as a standalone algorithm, as part of a modular software library suite, as well as with a VoIP stack. Contact us to discuss your G.729 vocoder application requirements.
Platforms
VOCAL’s G.729 Annex D voice compression algorithm is optimized for performance on leading DSPs and RISC/CISC processors from TI, ADI, AMD, ARM, Intel and other vendors. VOCAL offers the G.729 codec as a standalone algorithm, as part of a modular software library suite, as well as with a VoIP stack. Please contact us to discuss your G.729 vocoder application requirements.
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