A direct computation of DCT coefficients for a signal block taken from two adjacent blocks

A direct computational algorithm for obtaining the DCT (discrete cosine transform) coefficients of a signal block taken from two adjacent blocks is proposed. This algorithm reduces the number of both multiplications and additions/subtractions compared to the traditional method, which requires inverse transforms of two received coefficient blocks followed by a forward transform. The proposed algorithm is efficient and useful for speech coding and image processing, especially for real-time applications