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ITU-T G.729 Annex D Speech Coder for the TMS320C55x Generation |
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The ITU-T G.729 Annex D fixed-rate speech coder provides toll quality at very low bandwidth. G.729 compresses narrowband linear speech signals at a sample rate of 8kHz to 8kbps, using Conjugate-Structure, Algebraic Code-Excited Linear Prediction (CS-ACELP). The encoder extracts the parameters of the CELP coding model from 10-msec frames. G.729 Annex D compresses speech to a lower bit-rate of 6.4kbps with somewhat lower fidelity compared to the original 8.0kbps rate.
G.729 Annex D encoder is widely used in applications that require robust quality over low bandwidth, including videoconferencing, internet, multimedia communications, satellite communications, and store/forward.
The G.729 Annex D is part of the DSP Wizard G.729 suite for TMS320C55x, which is comprised of five separate products:
| Algorithm | Complexity | SID Frames | Bit-rate |
|---|---|---|---|
| G.729 | High | No | 8.0kbps |
| G.729 Annex A | Low | No | 8.0kbps |
| G.729 Annex B | High | Yes | 8.0kbps |
| G.729 Annex A Annex B | Low | Yes | 8.0kbps |
| G.729 Annex D | Medium | No | 6.4kbps |
DSP Wizard’s G.729 Annex D implementation was designed for low resource requirements without sacrificing quality. It executes at 9.0 mips for worst-case data.
| G.729 Annex D | Encoder | Decoder | Full Duplex |
|---|---|---|---|
| Program Code Memory (Kbytes) | 10.5 | 5.5 | 14.6 |
| Program Table Memory (Kbytes) | 0.0 | 0.0 | 0.0 |
| Data Table Memory (Kbytes) | 5.4 | 4.8 | 6.1 |
| Per Channel Data Memory (Kbytes) | 1.2 | 0.8 | 2.0 |
| Stack Memory (Kbytes) | 0.3 | 0.3 | 0.3 |
| Interrupt Latency (cycles) | 0 | 240 | 240 |
| Call Period (ms) | 10 | 10 | 10 |
| Processor Load: Worst-Case (MHz) | 7.0 | 2.0 | 9.0 |