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 one block of said group from a second part of said at least one enhancement layer, and reconstructing the at least one block from said residues and from said processed at least one region.