Abstract: A video encoder and decoder are provided for processing a sequence of animated pictures in such a way that an interactive game, such as a puzzle for instance, may be played. Each picture of a movie sequence is divided into a predetermined number of pieces that are then randomly coded (according to the MPEG-4 standard), transmitted and/or stored, decoded and displayed. It is then possible to play with the pieces to reorder them while they are in motion (with possible associated audio), according to predefined rules and ends of scenarios. The left and right buttons of a mouse, or a similar control device, are used to displace either one piece, or a group of attached pieces respectively, in order to verify if the proposed location for a piece is free and possible (no contradiction with any other surrounding piece) and then to drop said piece on the new spot, or, on the contrary, if some contradiction is detected, send back the piece (or, respectively, the group of attached pieces) to its previous location.

Abstract: The invention relates to the domain of multi-media scene description. In a conventional manner a scene description stream comprises coded data relating to scene descriptions and coded data relating to scene modifications. Access points to the stream are provided to permit a user to get into the stream at whatever instant. These access points are formed by data relating to a complete scene description. In accordance with the invention, when a scene description is coded, the coded data resulting therefrom are stored in a memory. And access points inserted into the stream are formed by the coded data stored in this memory. One thus avoids to code a new scene description every time an access point is to be inserted into the stream.