New recursive algorithms for the forward and inverse MDCT

Abstract

Forward and inverse MDCT (modified discrete cosine transform) are two of the most computationally intensive operations in the MPEG audio coding standard. We derive sinusoidal recursive formulas for transforming kernels of the MDCT and IMDCT. Then we efficiently implement general length MDCT and IMDCT using the regressive structure derived from the sinusoidal recursive formulas. The proposed regular structure is particularly suitable for parallel VLSI realization. Our solution requires less hardware than a recently proposed one.