FAST ALGORITHMS FOR COMPUTATION OF 5-POINT DCT-II, DCT-IV, AND DST-IV, AND ARCHITECTURES

摘要

FIELD: information technology.;SUBSTANCE: more efficient encoder/decoder is provided in which an N-point MDCT transform is mapped into smaller sized N/2-point DCT-IV, DST-IV and/or DCT-II transforms. The MDCT may be systematically decimated by factor of 2 by utilising a uniformly scaled 5-point DCT-II core function as opposed to the DCT-IV or FFT core functions used in many existing MDCT designs in audio codecs. Various transform factorisations of the 5-point transforms may be implemented to more efficiently implement a transform.;EFFECT: efficient implementation of smaller transforms, desirably for implementing a bigger transform, using a smaller basic transform.;52 cl, 32 dwg