METHOD OF CODING A VIDEO SIGNAL FOR TRANSMISSION IN A RESTRICTED BANDWIDTH

摘要

A video signal is coded for transmission in a restricted bandwidth by sub-dividing a frame of picture information into a set of constituent blocks, measuring the amount of picture activity in each block, sampling the information in each block at a rate related to the amount of picture activity in that block, and adding to the coded block a supplementary signal indicating the sampling rate used for the block. Thus a decision is made on a block-by-block basis as to whether the block is transmitted with full accuracy or whether it can be adequately reconstructed from the previous frames.