LOW COMPLEXITY TRANSFORM CODING USING ADAPTIVE DCT/DST FOR INTRA-PREDICTION

摘要

PURPOSE: A low complexity transform coding method using a discrete cosine transform (DCT) method and a discrete sine transform (DST) method is provided to execute video compression including efficiency and low complexity. CONSTITUTION: A decoder maps coefficients of a video bit string on a coefficient matrix of M by N size according to an intra prediction mode of the inputted video bit string. The decoder determines a DCT method or a DST method according to the intra prediction mode (1220). The decoder determines the DCT method or the DST method in order to calculate the approximation of error prediction residual rates (1240). [Reference numerals] (1210) De-quantize; (1220) Decide which a DCT method or a DST method should be applied as a vertical conversion method based on an internal forecast mode; (1230) Use a M-point DCT method as a vertical conversion method; (1235) Use a M-point DST method as a vertical conversion method; (1240) Decide which a DCT method or a DST method should be applied as a horizontal conversion method based on an internal forecast mode; (1250) Use a N-point DCT method as a horizontal conversion method; (1255) Use a N-point DST method as a horizontal conversion method; (1260) Reorganize by using an internal anti-forecast method