Contract DSP software development

Vocoder G.723.1

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
  • Loop System Co. Ltd.
  • Improv Systems, Inc
  • 74ZE Engineering, Inc
  • Parabyte Co. Ltd.
  • Pulsar Group of companies
  • EasyPQ Technologies Pvt. Ltd.
  • NIC Test Electro
  • Telecomequipment