Frame-to-frame compression of vector quantized signals and other

Abstract

Post-quantization processing is disclosed in which frames of data are organized into frames of input vectors. For each input vector, the quantizer identifiers a closely matching codebook vector. The quantizer generates a compressed signal by replacing each input vector in a frame with an ID code of a closely matching codebook vector. On subsequent frames, the quantizer further processes ID codes to achieve additional compression. In one embodiment, the ID codes from one frame are compared to the corresponding ID codes in the previous frames. If the ID code from the subsequent frame (new ID code) is the same as the corresponding ID code from the previous frame (old ID code), the new ID code is eliminated from the frame and a tag bit is set to indicate that the ID Code was eliminated. Similarly, if the new ID code represents a vector which is only slightly different from the vector represented by the old ID code, the new ID code is replaced with a tag bit. In this way, transmission of the subsequent frames requires only the transmission of vectors which differ by a significant amount from the prior frame. In other embodiments, other post processing methods are used. For example, lossless coding techniques, such as the socalled Lempel-Ziv and Huffman codes are discussed.