Sican Gmbh

Gerriet Muller

Klaus Gruger

Ulrich Schneider

Sven Fiedrich

A method and circuit for forward and backward transform of a DCT and IDCT, based upon the so called 'Loeffler-architecture, is disclosed. The circuit has a chip area as small as possible. The method has a small number of calculation operations and a high accuracy of calculation. The respective structures of the disclosed DCT and IDCT are as similar as possible. Based upon the high commonality of this DCT and IDCT pair, using three butterfly stages and one correction stage, the algorithms are adapted to the desired processing performance. Two of the butterfly stages are executed in a simple time multiplexed operation in common circuitry. The data is permuted after the computation of one butterfly stage and fedback via delay lines into the common circuitry for the other butterfly stage. The other stages are operated without a stepwise time multiplexed operation.

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Berlin, Germany

Gerriet Muller