1. A method of merging entropy codebook application ranges within an audio signal, comprising: obtaining an audio signal that includes quantization indexes, identification of segments of said quantization indexes, and indexes of entropy codebooks that have been assigned to said segments, with a single entropy codebook index having been assigned to each said segment; identifying potential merging operations in which specified segments potentially would be merged with each other; estimating bit penalties for the potential merging operations; and performing the potential merging operation having the lowest estimated bit penalty.