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Video codec, for a videophone terminal of an integrated services digital network

  • US 5,367,331 A
  • Filed: 02/23/1993
  • Issued: 11/22/1994
  • Est. Priority Date: 02/24/1992
  • Status: Expired due to Term
First Claim
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1. A video codec particularly for videophone applications, and more particularly for a videophone terminal of an integrated services digital network, said codec being organized to receive firstly image signals coming from a local television camera so as to transmit them, after compressing and encoding them, to a compatible remote video decoding unit, in particular of another video codec, via a digital transmission line, in particular of the telephone type, and secondly image signals similarly compressed and encoded by a remote video encoding unit, in particular of said other video codec, the similarly compressed image signals being received via the digital transmission line, and then being decompressed and decoded for a television screen receiver locally connected to said video codec, wherein said video codec includes a processing unit co-operating with a single external memory plane both to compress and encode data to be transmitted, and also to decompress and decode received data, with the assistance of time-shared internal operational components;

  • wherein the processing unit includes a discrete cosine transform operator and a quantifier connected together in series and time shared in association with a loop filter firstly, directly and then inversely as regards the assembly comprising the transform operator and the quantifier, for processing macroblocks of image to be transmitted, and secondly, inversely as regards said assembly, for processing macroblocks of received image.

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