IntMDCT - a link between perceptual and lossless audio coding
The modified discrete cosine transform (MDCT) is widely used in modern perceptual audio coding schemes. We present an integer approximation of this lapped transform, called IntMDCT, which is derived from the MDCT using the lifting scheme. This reversible integer transform inherits most of the attractive properties of the MDCT, exhibiting a good spectral representation of the audio signal, critical sampling and overlapping of blocks. This makes the IntMDCT well suited for both lossless audio coding as well as for combined perceptual and lossless audio coding. A scalable system is presented providing a lossless enhancement of perceptual audio coding schemes, such as MPEG-2 AAC (advanced audio coding).