Multi-stage vector quantization with efficient codebook search

摘要

A method of using a computer (11) to perform a multi-stage vector quantization process (13a). At each stage of the process (13a) subsequent to the first stage, input vectors from the previous stage are used to search a codebook (13b) for code-vectors that minimize distortion. (FIG. 2) The search is structured so that each stage is performed with an outer loop that calculates components of distortion that do not depend on the input vector value. An inner loop, which does depend on input vector values, is used to calculate distortion values and to maintain a list of the current best output code-vectors. (FIG. 3). The first stage is a special case, having only one input vector, but is otherwise performed like the subsequent stages.