METHOD FOR ENCODING AND DECODING IMAGES, ENCODING AND DECODING DEVICE, AND CORRESPONDING COMPUTER PROGRAMS

摘要

The invention relates to an encoding method including cutting out (C1) the image from a plurality of blocks (MB) capable of containing symbols belonging to a predetermined set of symbols, grouping (C2) blocks in a predetermined number (P) of subsets of blocks (SE1, SE2,...SEk,...,SEP), encoding (C3), using an entropic module, each of said subsets of blocks, by combining digital information with the symbols of each block of a subset in question, said encoding step including, for the first block of the image, a sub-step (C33) of initializing status variables of said entropic encoding module, and then generating at least one sub-stream of data representative of at least one of said subsets of encoded blocks. In the event the current block is the first block being encoded of a subset of blocks in question, the probabilities of a symbol appearing for said first current block are those determined for a predetermined encoded and decoded block of at least one other subset. In the event the current unit is the last encoded unit of the subset in question, all of the digital information that was associated with the symbols during the encoding of the blocks of the said subset in question are written (C45) in the sub-stream representative of at least said subset in question, and the initialization sub-step is implemented (C46).