A proposed fast ACELP codebook search

The ACELP coding algorithm has been widely adopted in standard speech coders due to the advantages of codebook storage and the efficient search schemes. Especially, the focused search and depth first tree search that are very efficient methods to reduce dramatically the search complexity while providing a good sub optimal solution. The pulse location prediction and pulse replacement are already proposed to reduce complexity and provide improvements. In this paper, we propose two fast methods based on pulse replacement and pulse location prediction. In these proposed methods, the total computations are reduced with almost imperceptible degradation in performance and even better efficiency for large number of code replacements. The efficiency and complexity of proposed methods are examined on GSM-EFR coder and compared with depth first tree, pulse replacement and pulse location prediction methods.