An Efficient Algebraic Codebook Search For G.729 Standard

• Main Authors: Ying-Jang Su, 蘇盈彰
• Other Authors: Cheng-Yu Yeh
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/36331534793527535039

碩士 === 國立勤益科技大學 === 電子工程系 === 97 === 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. Therefore, the goal of this paper is to reduce the computational complexity of G.729 encoding phase. In the G.729 encoding phase, the algebraic codebook search is employed to obtain the four pulse positions in the codebook. However, it occupies the largest computation in the encoding phase. A sub-optimal search algorithm is employed here to reduce the computation required for the search procedure of fixed codebook. Two experiments including the computational complexity and the speech with PESQ-MOS score were used to examine the proposed method. In comparison with the conventional algorithm, the 80.283% of computation can be eliminated with a slight degradation of PESQ-MOS from 3.923 to 3.591. Experimental results confirm that the proposed method has been implemented successfully.