Video codec for ISDN

Video codec (01), especially for an integrated services digital network videophone terminal, provided in order to receive, on the one hand, picture signals from a television camera (2) so as to transmit them, after compression and coding, to a remote video decoding unit by way of a digital transmission line (L) and, on the other hand, picture signals, similarly processed, via this line, so as to expand and decode them for a receiver with television screen (4') linked locally thereto. The codec includes a processing unit (054), of integrated circuit type, ensuring, in tandem with a single external memory plane (055), both the compression and coding of the data to be transmitted and the expanding and decoding of the data received, with the aid of time-sharing operational elements for applying known processes, at the transmitting and receiving ends.