Abstract: A method and apparatus is disclosed for a fast, one-dimensional, discrete cosine transform (1D DCT) of eight samples, and for a fast, one-dimensional, inverse discrete cosine transform (1D IDCT) for eight coefficients, requiring five parallel additions, five parallel subtractions and one parallel multiply operation. According to one embodiment, the parallel additions and subtractions are executed by performing a parallel add/subtract operation. The data are manipulated in a processor operable to execute add, subtract and multiply operations on a plurality of pairs of data values in parallel. According to a preferred embodiment of the invention, this processor is an associative memory array, typically consisting of several thousands of memory words. The inherent scalability of the associative memory enables increasing throughput by simply increasing the size of the associative memory, enabling performing the 1D DCT for large numbers of samples.

Abstract: A method of bit rate control and block allocation for discrete cosine transform (DCT) image signal compression includes the steps of (a) partitioning the image signals in blocks representing portions of the total image, (b) calculating DCT coefficients for image data in all blocks, (c) obtaining a measure of block activity (BACT) for each block based on DCT coefficients and for the total image activity (ACT) as a sum of the measures of all block activity, and (d) determining a code allocation factor (AF) for each block based on the ratio of block activity (BACT) to target code volume (TCV data) for the coded image data. Thereafter, step (e) includes allocating bits for each block using the allocation factor (AF) for each block and the target code volume (DCV data).