PERFORMANCE METHOD FOR INVERSE DISCRETE COSINE TRANSFORMATION PROVIDED WITH SINGLE INSTRUCTION MULTIPLE DATA INSTRUCTION, EXPANSION METHOD FOR COMPRESSED DATA, EXPANSION DEVICE FOR COMPRESSED DATA SIGNAL AND COMPUTER PROGRAM PRODUCT

摘要

PROBLEM TO BE SOLVED: To provide a device and a method for performing inverse discrete cosine transformation(IDCT) relating to the expansion of compressed data.;SOLUTION: A first unidirectional IDCT 158 for bringing plural first unidirectional IDCT coefficients 180 is performed and then, a second unidirectional IDCT 164 for bringing plural second unidirectional IDCT coefficients 184 are performed. At the time of executing the first, and second unidirectional IDCT 158 and 164, first plural intermediate butterfly calculation performs plural intermediate multiplications for bringing plural initial products and plural intermediate additions for bringing intermediate products. The plural intermediate additions are maintained to be 16 bits or less by the rounding scheme of RNP. The rounding and shifting of the plural second unidirectional IDCT coefficients following the second unidirectional IDCT are performed by utilizing the rounding scheme of RAZ for bringing plural output coefficients satisfying an IEEE 1180 standard.;COPYRIGHT: (C)2001,JPO