Patent ID: 7136890

Claim:
In an inverse discrete cosine transform (IDCT) device used to decode received data, the IDCT device comprising: a column one-dimensional IDCT for separating input data of a column direction to a primary multiplication matrix and a secondary multiplication matrix, and sharing a multiplier for the same cosine constant so as to sequentially perform a primary multiplication and a secondary multiplication; a first accumulator for storing a primary multiplied result of the column one-dimensional IDCT in a first clock, and for adding the stored result and a secondary multiplied result in a second clock, and outputting the added result; a transpose matrix section for performing a column-row transposition on the output of the first accumulator; a row one-dimensional IDCT for separating data of a row direction outputted from the transpose matrix section to a primary multiplication matrix and a secondary multiplication matrix, and sharing a multiplier for the same cosine constant so as to sequentially perform a primary multiplication and a secondary multiplication; and a second accumulator for storing a primary multiplied result of the row one-dimensional IDCT in a first clock, and for adding the stored result and a secondary multiplied result in a second clock, and outputting the added result.