Coding arrangement including variable length encoder incorporating a buffer filling control based on averaged block quality, and an associated decoding device

Claim 1

A coding arrangement having an input for receiving packets of information blocks and an output terminal, said arrangement comprising: (a) a variable length coding means coupled to said input, for providing coded information at a coder output; (b) buffer means coupled to said coder output, for receiving said coded information and for providing said coded information at said output terminal at a fixed rate; (c) regulating means coupled to said variable length coding means and said buffer means, for defining for each information block, a quality value as a function of the real number of bits utilized by said variable length coding means to code the information block and a residual quantity defining the number of bits contained in the buffer means after said coding, said regulating means comprising in combination: i. means for determining an average quality for each packet of information blocks; ii. means for providing for each information block the number of bits corresponding to the average quality of its respective packet and for calculating for each information block a difference value between its said respective number of bits and the real number of bits of its respective packet; iii. means for accumulating for each packet, the difference values calculated for its respective information blocks; iv. means for supplying a fill quantity to said buffer means which represents the ratio between said accumulated difference values and said residual quantity; and v. means for supplying a corrected said average quality value as a function of said fill quantity.