Abstract: A compressed transcoded digital image signal is formed from a compressed original digital image signal having digital data organized in blocks. A data block in one of the compressed signals between the compressed transcoded digital image signal and the compressed original digital image signal is selected by identifying the spatial position of the data block in one of the compressed signals. The spatial position of a dual data block corresponding to the selected data block is identified in the non selected compressed signal, having regard to a given geometric transformation applied to this block. The data block belonging to the compressed original signal is decoded and the given geometric transformation is applied to the selected, decoded data block. The geometrically transformed data block is coded and the first, coded data block is inserted in the compressed transcoded image signal at the position of its dual block.

Abstract: A method of ordering bits in an N-bit status word (s[c]) adapted to represent the state of a coefficient (c) during an entropic encoding of the coefficient in several passes is adapted to modify the value of the last bit N?1 of the status word (s[c]), representing the sign of the status word (s[c]), according to the significance of the coefficient (c). A method for the entropic encoding of a coefficient (c) in several encoding passes using this status word (s[c]) comprises a step of comparing the value of the status word (s[c]) with the value 0 in order to determine whether a first condition is satisfied and a step of applying the first encoding pass to the coefficient (c) when the first condition is satisfied.

Abstract: A method of ordering bits in an N-bit status word (s[c]) adapted to represent the state of a coefficient (c) during an entropic encoding of the coefficient in several passes is adapted to modify the value of the last bit N-1 of the status word (s[c]), representing the sign of the status word (s[c]), according to the significance of the coefficient (c).