A method, comprising encoding a video wherein encoding the video comprises, for at least one current block from a picture of said video: determining a splitting mode for the current block among a set of candidate splitting modes that includes a no splitting, a horizontal splitting, a vertical splitting and a quad-tree splitting, according to rate-distortion costs determined for the current block in each of the candidate splitting modes, the splitting mode determined being the candidate splitting mode that provides a lowest rate-distortion cost, and encoding the current block according to the determined splitting mode; wherein determining the splitting mode for the current block comprises recursively splitting the current block into subblocks according to each of the candidate splitting modes, and for each of the candidate splitting modes, determining a rate-distortion cost for each of the subblocks obtained from the candidate splitting mode, wherein determining a rate-distortion cost for a subblock not being split comprises: determining, for the subblock, if a value of a parameter associated to the subblock, equals to a first value indicating that no coding parameters have been previously determined for the subblock, if the value of the parameter equals to the first value, determining for the subblock the rate-distortion cost by determining coding parameters of the subblock and setting the parameter associated to the subblock to a given value that indicates that coding parameters have been determined for the subblock, wherein the given value equals to a second value when the subblock is a first subblock of a block in a scanning order of subblocks of the block split according to a first splitting mode, and the given value equals to a third value when the subblock is not a first subblock of the block in the scanning order of the subblocks of the block, otherwise, if the value of the parameter associated to the subblock equals to the second value, setting the coding parameters and rate distortion cost of the subblock to coding parameters and rate distortion cost previously determined for another subblock of the block when the block is split according to a second splitting mode, wherein the other subblock is located at a same position in the picture as the subblock and the other subblock has a same width and same height as the subblock; otherwise, the value of the parameter associated to the subblock equalling to the third value, determining the rate-distortion cost for the subblock by determining, for the subblock, coding parameters of the subblock using the coding parameters previously determined for the other subblock as a starting point. determining a splitting mode for the current block among a set of candidate splitting modes that includes a no splitting, a horizontal splitting, a vertical splitting and a quad-tree splitting, according to rate-distortion costs determined for the current block in each of the candidate splitting modes, the splitting mode determined being the candidate splitting mode that provides a lowest rate-distortion cost, and encoding the current block according to the determined splitting mode; wherein determining the splitting mode for the current block comprises recursively splitting the current block into subblocks according to each of the candidate splitting modes, and for each of the candidate splitting modes, determining a rate-distortion cost for each of the subblocks obtained from the candidate splitting mode, wherein determining a rate-distortion cost for a subblock not being split comprises: determining, for the subblock, if a value of a parameter associated to the subblock, equals to a first value indicating that no coding parameters have been previously determined for the subblock, if the value of the parameter equals to the first value, determining for the subblock the rate-distortion cost by determining coding parameters of the subblock and setting the parameter associated to the subblock to a given value that indicates that coding parameters have been determined for the subblock, wherein the given value equals to a second value when the subblock is a first subblock of a block in a scanning order of subblocks of the block split according to a first splitting mode, and the given value equals to a third value when the subblock is not a first subblock of the block in the scanning order of the subblocks of the block, otherwise, if the value of the parameter associated to the subblock equals to the second value, setting the coding parameters and rate distortion cost of the subblock to coding parameters and rate distortion cost previously determined for another subblock of the block when the block is split according to a second splitting mode, wherein the other subblock is located at a same position in the picture as the subblock and the other subblock has a same width and same height as the subblock; otherwise, the value of the parameter associated to the subblock equalling to the third value, determining the rate-distortion cost for the subblock by determining, for the subblock, coding parameters of the subblock using the coding parameters previously determined for the other subblock as a starting point.