Briefly, in accordance with one embodiment on the invention, a method of compressing a data set includes the following. In multiple passes, each data signal in the data set is categorized into a category of a predetermined set, and, for selected categories of the predetermined set, the data signals for that category are coded using a codebook for that category. Briefly, in accordance with another embodiment of the invention, a method of decompressing a compressed data set includes the following. For compressed data signals in the data set in one category of a predetermined set of categories, a signal associated with the particular category is employed for the compressed data signal, and, for selected categories of the predetermined set, the compressed data signals for that category are decoded using a codebook for that category.