G.729自适应码书搜索算法的研究

Study on the Adaptive Codebook Search Algorithm in G.729 Speech Coding

G.729语音编码算法复杂,很大程度上要归因于码书搜索算法。为了降低码书搜索复杂度,G.729的简化版G.729A采用了自适应码书的偶样点开环基音搜索,使得编码复杂度大为降低,不过编码仍要花费很多的时间。通过对G.729码书搜索算法的研究,提出了对自适应码书的改进。改进了自适应码书搜索的G.729编码语音质量不低于G.729A的语音质量,但自适应搜索复杂度大大降低。

G. 729 speech coding algorithm which is complicated greatly ascribes to the codebook search algorithm. In order to reduce the code book search complexiity, G. 729A which is the simplified version of G. 729 adopted the even sample point open loop pitch search of the adaptive codebook. Although this makes the coding complexity significant drop, coding still needs to consume a lot of time. Based on the study of the G. 729 code book search algorithm, put forward to the improvement of adaptive code book. The speech quality of G. 729 of improved adaptive codebook search is not inferior to that of G. 729A, but the adaptive algorithm complexity reduces greatly.