In order to reduce search space efficiently

the codebook must be rearranged in the fast codeword search algorithms of vector quantization. Two kinds of algorithms are summarized in this paper. One is the codebook sorted by 1D characteristic value; the other is the codebook mapped into 2D adjacent ripples. Comparisons and analysis are conducted for these two kinds of fast algorithms in terms of the search space and encoding time. The criteria about how to use these two rearrangement method reasonably is also given in this paper.