Patent ID: 7570180

Claim:
A method of transforming a description of an encoded bit stream, the encoded bit stream comprising data packets, the description being written in a markup language, a group of one or more data packets being described in the description by an element, the element having at least one attribute containing a transformation tag, the method comprising: scanning the description to check for a transformation tag in accordance with a predetermined condition; generating an adapted description in which the elements, in which a transformation tag does not satisfy the predetermined condition, are removed; and generating an adapted encoded bit stream from the adapted description; wherein the encoded bit stream has a scalable format according to which several data layers are defined, and the transformation tag comprises an indication of the data layer to which the group of one or more data packets belongs; and wherein the transformation tag further comprises a packet identifier, and the predetermined condition is a condition of membership of a set of packet identifiers associated with a specific transformation to be achieved.