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Etablissement Public De Diffusion Dit 'telediffusion De France'

Viacess

Jean-Pierre Vigarie

Gilles Dubroeucq

Yves-Francois Dehery

The invention relates to an access control method controlling access to a broadcast digital dataflow previously scrambled. The method according to the invention includes the following steps:

Method and system for conditional access applied to protection of content

A method and an equipment for allocating to a television program, which is already conditionally accessed, a complementary conditional access. The television program is first received by means provided with access entitlements and the control words are restored. Complementary access control messages and complementary entitlement management messages corresponding to a complementary access control system are built up. The initial unmodified television program is rebroadcast, together with the complementary messages related to the complementary access control system.

Method and equipment for allocating to a television program, which is already conditionally accessed, a complementary conditional access

The device is for use in demultiplexing a MAC/PACKET incoming signal which comprises successive bursts of digital data distributed into packets, each packet consisting of useful data and a header having a channel number indicating one of a plurality of service components to which said packet is assigned, a continuity index IC and a header error protection code. The device has a circuit for generating all error-free configurations of a selected channel number and IC and corresponding to a respective service component; an encoder for encoding all error-free configurations into all possible theoretical header configurations having the error protection code; and a computer for computing the Hamming distances between each packet header in the incoming signal and all theoretical header configurations. Those packets for which the Hamming distance is not greater than a predetermined value are directed to an output interface.

Packet demultiplexing of a mac/packet broadcast signal

An image memory graphic terminal comprising an image memory constituted by memory planes, each plane incorporating a matrix system of memory points, a sequencer, a graphic display processor, a video signal generator, a video display receiver, a management microcomputer. According to the invention, the terminal also comprises a system for writing or recording in the image memory image texture signals, said system comprising

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Cesson-Sevigne, France

Jean-Pierre Vigarie