1. A method for decoding a scalable stream comprising a base layer and at least one enhancement layer, the method comprising: reconstructing at least one image from said base layer, decoding a first part of said at least one enhancement layer relating to a group of a plurality of blocks into decoded enhancement data which comprise at least one item of information for identifying at least one region of said reconstructed at least one image, processing said at least one region of said reconstructed at least one image identified by said at least one item of information, obtaining residues for at least a first block and a second block of said group from a second part of said at least one enhancement layer, wherein the residues for the first block are obtained from another image previously reconstructed and the residues for the second block are obtained from another image of the enhancement layer, and reconstructing the at least a first block and a second block from said residues and from said processed at least one region.