Process for coding a sequence of images, by a transformation and a plurality of variable-length codes, and devices for implementing this process

摘要

The invention relates to an enhancement to the coding process according to Claim 1 of the main patent, consisting essentially, in order to code each block of cosine coefficients, in: - counting the number n of non-zero coefficients C1...C14 in the block; - calculating, for each non-zero coefficient, a relative address which is the place value of this coefficient relative to the non-zero coefficient which precedes it in the set of coefficients of the block, ordered in a predetermined order; - coding the n relative addresses of the non-zero coefficients of the block, in the form of n variable-length codewords, according to a coding tree which is dependent upon the place value of each relative address of the n relative addresses; - then coding the n non-zero coefficients of the block in the form of n variable-length codewords, according to a coding tree which is dependent on the place value of the coefficient to be coded, in the set of all coefficients of the block, ordered in a predetermined order.