Method for decoding a coded data stream representative of a sequence of pictures, said pictures being divided into blocks of pixels with each of which at least one picture data is associated, said method comprising: - decoding (600, 700) at least one part of said stream representative of picture data of a current block into decoded data, - selecting (604, 706, 708) at least one brightness variation model from a set of at least two brightness variation models, - reconstructing (606, 710) said picture data of said current block from a reference block of a reference picture and from said decoded data by taking into account said selected brightness variation model, said method being characterized in that, said set of at least two brightness variation models comprising at least an additive brightness variation model and a multiplicative brightness variation model, selecting at least one brightness variation model (604, 706, 708) comprises: - calculating a first sum S1 of previously reconstructed picture data of neighbouring pixels of said current block, - calculating a second sum S2 of picture data of corresponding pixels in the reference picture, - calculating a third sum S3 of squared picture data of corresponding pixels in the reference picture, - calculating a fourth sum S4 of products of the previously reconstructed picture data of the neighbouring pixels of said current block and the picture data of corresponding pixels in the reference picture, and - selecting said multiplicative brightness variation model if Δd is positive and said additive brightness variation model otherwise, with Δ d = (1+ b̂ 2)* S 3 -2* S 4 -N * â 2, where: - b̂ is the parameter of the multiplicative brightness variation model and is equal to S4/S3, - â is the parameter of the additive brightness variation model and is equal to (S1-S2)/N, - N is the number of neighbouring pixels of said current block. - decoding (600, 700) at least one part of said stream representative of picture data of a current block into decoded data, - selecting (604, 706, 708) at least one brightness variation model from a set of at least two brightness variation models, - reconstructing (606, 710) said picture data of said current block from a reference block of a reference picture and from said decoded data by taking into account said selected brightness variation model, - calculating a first sum S1 of previously reconstructed picture data of neighbouring pixels of said current block, - calculating a second sum S2 of picture data of corresponding pixels in the reference picture, - calculating a third sum S3 of squared picture data of corresponding pixels in the reference picture, - calculating a fourth sum S4 of products of the previously reconstructed picture data of the neighbouring pixels of said current block and the picture data of corresponding pixels in the reference picture, and - selecting said multiplicative brightness variation model if Δd is positive and said additive brightness variation model otherwise, with Δ d = (1+ b̂ 2)* S 3 -2* S 4 -N * â 2, where: - b̂ is the parameter of the multiplicative brightness variation model and is equal to S4/S3, - â is the parameter of the additive brightness variation model and is equal to (S1-S2)/N, - N is the number of neighbouring pixels of said current block. - b̂ is the parameter of the multiplicative brightness variation model and is equal to S4/S3, - â is the parameter of the additive brightness variation model and is equal to (S1-S2)/N, - N is the number of neighbouring pixels of said current block.