The integer MDCT and its application in the MPEG layer III audio

The MPEG audio layer III is an efficient audio coding scheme which gives perceptually high quality audio while achieving very high compression. The modified discrete cosine transform (MDCT) is a filterbank used by the MPEG audio layer III to provide finer spectral resolution by subdividing in frequency the subband outputs from the previous layers. Recently fast and lossless structures for the MDCT used in the layer III have been developed which use integer coefficients for their implementation. In this paper we evaluate the performance of the integer implementation of the MDCT by incorporating in the MPEG layer III codec and compare with that of a standard implementation. The comparison is done based on the decoded waveform, spectrogram and by conducting a subjective survey. The complexity of the lossless structure is also evaluated.