Abstract: A method system for data reduction of digital video signals based on vector quantization of vectors formed from coefficients of a discrete cosine transform of pixel blocks. The coefficients are grouped into subbands and both scalar and vector quantization are used. Vector quantization is implemented either directly on the vectors or on vectors formed from inter-frame differences between the transformed vectors. The vector quantization searching routine is in accordance with the Voronoi regions resulting from an off-line codeword clustering method using a minimum distance criterion.

Abstract: A method and system for video motion compensation in which an overall interframe motion vector is divided into a relative block motion vector and a subblock motion vector. Image reconstruction is achieved by adjusting the delay between the synchronization pulse and the start of the pixel data according to the subblock motion vector, and accessing stored data from memory according to the relative block motion vector. Accessing memory in a block-quantized format ensures that page mode accesses are confined to the same memory row.

Abstract: A scrambler system is provided for the detection and separation of synchronization signals from data signals, and for the scrambling of the data signals such that no long and repeatable series of one's or zero's are present in the data stream. The scrambler provides an exclusive OR operation to a pseudo random number sequence and the data signals prior to their modulation and transmission. At the receiving end, the identical pseudo random sequence is exclusive OR'ed with the demodulated data, causing the data to be restored to its original form. Thus, an undesirable continuous stream of ones or zeros is eliminated by the scrambler prior to its transmission.