Study on the Algebraic Codebook Optimization Search Method based on Grade and Subsection
Jing Li · Journal of Signal Processing · 2013
Algebraic codebook is a popular fixed codebook structure;its searching method directly influences decoding speech quality and computational complexity.The paper puts forward a kind of algebraic codebook GSOS(Graded and Subsection Optimization Search) Method.The method fuses the advantages of pulse replacement,subsection searching and grade optimization method.It first creates good initial codebooks;then proceeds codebook searching by subsection for replacing multiplication by the operation of addition;at the same time,the pulses are graded according to contribution degrees for improving the efficiencies of pulses replacement optimization.By using the proposed method to fixed codebook searching stage of AMR-WB(Adaptive Multi-Rate Wideband Speech Codec),the experiment results showed that the proposed method can make the computational complexities of fixed codebook searching down to 13.75% of depth-first tree search procedure,but the decoding speech qualities were only reduced by 4.01%.The subjective auditory almost did not feel the difference.