BILINEAR ALGORITHMS AND VLSI IMPLEMENTATIONS OF FORWARD AND INVERSE MDCT WITH APPLICATIONS TO MP3 AUDIO

摘要

Provided herein are hardware efficient bilinear algorithms and methods to compute MDCT/IMDCT of 2̂n and 4.3̂n points. The algorithms and methods for composite lengths have practical applications in MP3 audio encoding and decoding. The MDT/IMDCT can be converted to type-IV discrete cosine transforms (DCT-IV). Using group theory, the methods decomposes DCT-IV transform kernel matrix into groups of cyclic and Hankel product matrices. Bilinear algorithms are then applied to efficiently evaluate these groups. When implemented in VLSI, bilinear algorithms have improved the critical path delays over existing solutions. For MPEG-1/2 layer III (MP3) audio, proposed herein are several different versions of unified hardware architectures for both the short and long blocks and the forward and inverse transforms.