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G.723.1 Speech Codeс software implements ITU-T G.723.1. 10-th order Linear Prediction Coder (LPC) filter is calculated and quantized with Predictive Split Vector Quantizer (PSVQ). A fifth order pitch predictor is used. Non-periodic component of the excitation is approximated with Multi-pulse Maximum Likelihood Quantization (MP-MLQ) excitation (for 6.3 kbits/s) or with algebraic-code-excitation (ACELP) (for 5.3 kbits/s) Vocoder G.723.1 Speech Coder processes signal with 30 ms frames length plus 7.5 ms look-ahead, total data processing delay is 37.5 ms. G.723 6.3 kbits/s bit rate provide high speech quality at low bit rate and moderate complexity, 5.3 kbits/s bit rate provide additional design flexibility.
G.723.1 features:
- Bit-exact with G.723.1 Annex A
- 16-bit linear PCM 8 KHz sampled data
- C API, Multichannel code
- Optimized C code
- VAD and CNG
G.723.1 memory/MIPS requirements for Texas Instruments TMS320C6400 platform:
- Coder 26.12/15.05 MIPS (for 6.3/5.3 kbit/s)
- Decoder 0.91/0.91 MIPS (for 6.3/5.3 kbit/s)
- 96.5 KB program and constant memory
- 1920 B data memory per channel,
Further optimization and porting to other DSP platform TI 54XX, 64XX, Blackfin and ARM is possible.
Official ITU-T recommendation G.723 and test vectors are available at G.723 standard
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