Abstract: Improved method and apparatus for vector quantization (VQ) to build a codebook for the compression of data. The codebook or "tree" is initialized by establishing N initial nodes and creating the remainder of the codebook as a binary codebook. Children entries are split upon determination of various attributes, such as maximum distortion, population, etc. Vectors obtained from the data are associated with the children nodes, and then representative children entries are recalculated. This splitting/reassociation continues iteratively until a difference in error associated with the previous children and current children becomes less than a threshold. This splitting and reassociating process continues until the maximum number of terminal nodes is created in the tree, a total error or distortion threshold has been reached or some other criterion. The data may then be transmitted as a compressed bitstream comprising a codebook and indices referencing the codebook.

Abstract: A signal processing system determines the characteristic of a signal for encoding or decoding by examining and classifying such signal, and then applies a transformation or inverse transformation to such signal. Depending on classification of the signal, various transforms or inverse transforms are applicable adaptively thereto.

Abstract: Improved method and apparatus for vector quantization (VQ) to build a codebook for the compression of data. The codebook or "tree" is initialized by establishing N initial nodes and creating the remainder of the codebook as a binary codebook. Children entries are split upon determination of various attributes, such as maximum distortion, population, etc. Vectors obtained from the data are associated with the children nodes, and then representative children entries are recalculated. This splitting/reassociation continues iteratively until a difference in error associated with the previous children and current children becomes less than a threshold. This splitting and reassociating process continues until the maximum number of terminal nodes is created in the tree, a total error or distortion threshold has been reached or some other criterion. The data may then be transmitted as a compressed bitstream comprising a codebook and indices referencing the codebook.

Abstract: Decoding and encoding of variable length data words and data strings is accelerated by testing for and processing more than one word or string per encoding or decoding cycle. In an encoding scheme wherein fixed length data words are encoded into variable length data strings, decoding is carried out by first receiving a data stream having a plurality of encoded data strings contained therein, and then testing at least a portion of the data stream to determine whether the portion contains one of a number of selected sets of multiple data strings. If the portion of the data stream contains one of the selected sets of multiple data strings, the multiple data strings are decoded into a corresponding set of multiple data words. This decoding procedure allows a plurality of encoded data strings to be decoded in a single decoding cycle. The procedure may be implemented using either a single lookup table or a set of split-level lookup tables.