An optimized algorithm for computing the modified discrete cosine transform and its inverse transform

This paper presents an optimized algorithm for the modified discrete cosine transform (MDCT) and its inverse transform (IMDCT) computation in MPEG audio. The proposed algorithm is based on the DCT of type II (DCT-II). By extracting a common kernel form from the MDCT and IMDCT, we can obtain an optimized computation of the MDCT and the IMDCT using a unified structure. Also, our proposed structure is more symmetrical and simple than those of the existing researches. Proposed algorithm is, moreover, very useful in implementing the parallel VLSI system structure of the MDCT and IMDCT.