Unified selectable fixed-coefficient recursive structures for computing DCT, IMDCT and subband synthesis filtering

In this paper, a unified fixed-coefficient recursive structure for computing the general length discrete transforms is proposed. After the regular data preprocessing, the general discrete transforms are simplified and converted into the simpler DCT, which is realized in a second-order infinite-impulse responses (IIR) filter. The proposed recursive structure only requires half the recursive cycles and also achieves more accurate results than the existing ones. Furthermore, the proposed algorithm can be applied to many popular transforms, such as subband synthesis filtering, inverse modified discrete cosine transform (IMDCT) and all discrete cosine transform (DCT) types. The proposed structure is extremely regular and more suitable for VLSI implementation.