Method and coding and decoding devices for picture transmission through a variable rate network

US4933762A · kind A · utility

Assignee

• Etat Francais, Represente par le Ministre des Pos Tes, Destelecommunicati ons et de l'Space-Centre National d'Etudes des Telecommunications (C.N.E.T.) · FR

Inventors

• Jacques Guichard · Paris, FR
• Gerard Eude · Torcy, FR

Key dates

• Filing date: Nov 28, 1988
• Grant date: Jun 12, 1990
• Expiry date: Nov 28, 2008

Classification

• Technology area (CPC H): Electricity
• CPC primary: H04N19/30
• WIPO field: Audio-visual technology
• WIPO sector: Electrical engineering

Abstract

The coding and decoding devices embodying the invention are connected by two paths, a main path and an auxiliary path, of a variable rate digital transmission network. When the main path is capable of dispatching the totality of the information rate that the coding device is able to issue, only a main coder and a main decoder, respectively of the coding and decoding devices, are active. When the main path is not capable of dispatching the totality of the picture information, an auxiliary coder and an auxiliary decoder, respectively of the coding and decoding devices, are also active and the auxiliary path dispatches the part of the information rate that cannot be dispatched by the main path. A decoder and a subtracter are provided in the coding device so as to estimate the part of information not transmitted by the main path.