The G.729 Voice Compression Codec Agreement Understanding And Realization Of The Dsp

H.323 is an ITU standard which provides several services including speech, data and multimedia etc. Being a speech compression coder protocol supported by H.323, G.729 has the advantages of low bit-rate and high speech quality and been selected by ITU-T as 8kb/s standard.Digital Signal Processing is widely applied for its realtime process ability. The principles and implementation of G.729 algorithm on DSP processor are discussed in this paper. To meet the requirement for data large dynamic range, high precision and realtime processing, Texa Instrtument high performance 32-bit floating-point DSP TMS320C6713 is selected.Firstly it introduced the algorithm of G.729 with Conjugate-Structure Algebraic-Code-Excited-Linear-Prediction. It uses three new techniques in order to get low bit-rate and high speech quality, which are quantization and interpolation for LSP coefficients, pre-selection for codebook search and prediction for vector quantization of gains.Secondly this paper discussed the hardware environment.Finally, this paper discussed the software system design based on above hardware platform, including the DSP initialization program, the interrupt request service and speech coding. It also proposed some effective optimized methods according to the characteristics of the algorithm and DSP chip.Simulations show the algorithm can considerably reduce the calculation burden and the output speech has a high reconstructed quality.