The invention relates to a method for encapsulating a plurality of data substreams encoded in a bit stream, an encoded data substream being obtained by means of entropy encoding of a symbol subsequence representing an image or a series of images, said method including a step of creating a bit stream that encapsulates said plurality of substreams. According to the invention, said method is special in that it includes the following steps: - grouping data substreams into substream pairs according to an iterative traversal order predetermined from said plurality of substreams; - from a pair, obtaining a symmetrical pair by means of reversing a data order making up the second substream of the pair; and - concatenating the pairs obtained within a sequence. Said method is also special in that - the step of creating the bit stream includes encapsulating said sequence and information related to a number of substreams and related to the sizes of pairs of symmetrical substreams.