A method and apparatus for performing vector quantization in a video coder. The method includes obtaining a video frame and segmenting it into coding blocks of predetermined size. A predetermined number of the coding blocks is transferred to a first cache memory. A predetermined portion of a codebook is transferred into a first section of a second cache memory which is capable of being rotated or having addresses associated with bytes in the second cache memory interchanged or offset by a specified amount. Concurrently with computing the vector quantization for the first portion of the codebook with respect to the coding blocks in the first cache memory, a second section of the codebook is transferred into a second section of the second cache memory. The number of coding blocks transferred to the first cache memory is selected so that transferral of the second section of the codebook is completed at the same time as or prior to completion of the computation of the vector quantization. The second cache memory may be rotated so that the process may be repeated for the remaining sections of the codebook with minimal or no delay, thereby permitting vector quantization to be performed in real time video coders.
CROSS-REFERNCE TO RELATED APPLICATIONS
This application is related to U.S. patent application Ser. No. 08/399,084, Attorney Docket No. Rosenberg 2, entitled "Apparatus and Methods for Determining an Initial Huffman Coding Rate"; U.S. patent application Ser. No. 08/400,706, Attorney Docket No. Rosenberg 3, entitled "Apparatus and Methods for Selectively Reducing a Huffman Coding Rate"; and U.S. patent application Ser. No. 08/400,707, Attorney Docket No. Rosenberg 4, entitled "Apparatus and Methods for Performing Huffman Coding", which are all commonly assigned to the assignee of the present invention, and which are filed concurrently herewith. The disclosures of these related Applications are incorporated herein by reference in their entirety.
Processing of picture image compression coding is divided into a plurality of processing steps and programs for the respective steps are stored in a memory. Based on capacity of the memory, at least one of a number of frames, a number of lines and a number of block lines is set as a division unit by which each step conducts processing. Processing corresponding to a program stored in the memory is executed for a set division unit.
A method and an apparatus for encoding an image signal. The apparatus includes an acquisition module disposed to receive the image signal. A first processor is coupled to the acquisition module. At least one encoder processor is coupled to the first processor. The at least one encoder processor produces an encoded image signal under control of the first processor. The method includes the steps of converting an input image signal into a predetermined digital format and transferring the digital format image signal to at least one encoder processor. The method further includes the step of applying, at the at least one encoder processor, a hierarchical vector quantization compression algorithm to the digitized image signal. At the next step, a resultant encoded bit stream generated by the application of the algorithm is collected. The method and apparatus of the present invention may be used in conjunction with an ordinary modem to transmit and/or receive audio, video sequences or still images.
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.
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.
Apparatus and methods are provided for generating an output signal representing an initial Huffman Coding rate for use in compressing a received digital signal. The digital signal includes a plurality of digital sets wherein ones of the digital sets are non-unique. Ones of the digital sets are stored and an indicator is associated with each. The indicator represents the probability of occurrence, or frequency, of the associated digital set within the digital signal. While more than one associated indicator remains stored, pairs of the associated indicators are selectively combined and each of the selectively combined pairs of associated indicators are accumulated to determine the initial Huffman Coding rate. The initial Huffman Coding rate is used to compress the digital signal.
