Algebraic codebook search implementation on processors with multiple data paths

摘要

A method for codebook search in an algebraic code-excited linear prediction (ACELP) encoder is implemented with a multiple data path processor. The invention is particularly applicable in speech coders based on the ITU standards G.729 and G.723.1, and as applied to GSM adaptive multi-rate WB. Processors with multiple data paths are used efficiently in the present invention, whereby the inner loop search is faster. Pulse positions over which the codeword search is done are expediently grouped into subsets, and the search conducted using the processor parallel data paths. The number of pulses and the number of loops can be four, or chosen as desired. The codebook search expediently includes a second step of conducting a search among the best pulse positions corresponding to the innermost loop to arrive at a final best position.