Effective complexity reduction for G.729 standard

G.729 standard has been widely used in the VoIP system. But the computational complexity is too large to real-time work via low-end DSP chip or soft-DSP on embedded devices. Even though the G.729A, it is still hard to implement. In this paper, three methodologies for effective complexity reduction of G.729 are proposed. The sub-optimal algorithm is employed to the search procedure of fixed codebook; the discontinuous pitch estimation is used to the open-loop pitch analysis; and the hybrid two-stage VQ is assigned to the quantization of LSP coefficients. Experimental results confirm that the improved G.729 can be easy implemented and makes the real-time work available via soft-DSP on PDA phone (312MHz CPU, 64MB RAM). Totally 80.94% of computations can be eliminated in comparison with the G.729A as well as the performance of speech quality is still good. The efficiency of proposed methodologies is excellent.