Using the CS decomposition to compute the 8-point DCT

The aim of this paper is to evaluate the cosine-sine (CS) decomposition as a means for computing the 8-point Discrete Cosine Transform (DCT). By iteratively decomposing matrices after reordering their columns or rows, novel factorizations of the DCT matrix have been obtained that describe interesting algorithms for computing the transform. Some of them are only characterized by regular, symmetric data-flows, whereas others require a few computations. This suggests that our method can be used to search for innovative algorithms for other block transforms and to optimize hardware implementations.