Apparatus and method for scrambling, descrambling and secured distribution of audiovisual sequences stemming from DCT-based video coders

摘要

A process and system for secured distribution of video sequences in accordance with the digital stream format based on a DCT transformation constituted of frames including blocks with a fixed or variable size, at least a part of which blocks is calculated with the aid of temporal prediction and spatial prediction optimized from adjacent blocks, in which the prediction mode, cutting into blocks and decoding and filtering parameters for the display are indicted in the binary stream, wherein an analysis of the stream is made prior to transmission to client equipment to generate a modified main stream with the format of the original stream, and with complementary information of any format comprising the digital information suitable for allowing the reconstruction of these modified frames, then the modified main stream and the complementary information are transmitted separately during the distribution phase from a server to the equipment of an addressee.