Modified Discrete Cosine Transform: Its Implications for Audio Coding and Error Concealment
Ye Wang, Miikka Vilermo · Journal of the Audio Engineering Society · 2003
A study of the modified discrete cosine transform (MDCT) and its implications for audio coding and error concealment is presented from the perspective of Fourier frequency analysis. A relationship between MDCT and DFT via shifted discrete fourier transform (SDFT) is established, which provides a possible fast implementation of MDCT employing a fast Fourier transform (FFT) routine. The concept of time-domain alias cancellation (TDAC), the symmetric and nonorthogonal properties of MDCT, is analyzed and illustrated with intuitive examples. New insights are given for innovative solutions in audio codec design and MDCT-domain audio processing such as error concealment.