A new IDCT-DFT relationship reducing the IDCT computational cost
Chaouki Diab, Mohamad Oueidat, Rémy Prost · IEEE Transactions on Signal Processing · 2002
This paper reconsiders the discrete cosine transform (DCT) algorithm of Narashima and Peterson (1978) in order to reduce the computational cost of the evaluation of N-point inverse discrete cosine transform (IDCT) through an N-point FFT. A new relationship between the IDCT and the discrete Fourier transform (DFT) is established. It allows the evaluation of two simultaneous N-point IDCTs by computing a single FFT of the same dimension. This IDCT implementation technique reduces by half the number of operations.