Some peculiar properties of the MDCT

Having established the interconnection between MDCT, SDFT (shifted discrete Fourier transform) and DFT, we have successfully applied the results in audio encoder design. This paper presents some new observations and analyses: (1) MDCT is not an orthogonal transform and this has an impact on audio coding, and (2) analysis of time domain alias cancellation (TDAC) during the window switching in the case of MPEG-2 AAC. Finally, we report some experimental results on the energy compaction properties of MDCT.

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