The design of a hybrid filter bank for the psychoacoustic model in ISO/MPEG phases 1,2 audio encoder

Abstract

The ISO/MPEG phases 1 and 2 audio compression are receiving a wide range of applications. In the encoding process of MPEG, the psychoacoustic model exploits audio irrelevancy which is the key role to achieve high compression ratio without losing audio quality. However, the Fourier transform (FT) which has been used by the two psychoacoustic models suggested in standard draft requires high computational complexity, and hence leads to high hardware and software cost for real-time applications. This paper presents a new design named the hybrid filter bank to replace the FT. The hybrid filter bank can be integrated with the psychoacoustic models and provides a much lower complexity than the FT. Also, this paper shows that the hybrid filter is more suitable for the stereo coding and hence can provide a better quality for the intensity stereo coding, which is the key technology for the MPEG 1 to achieve near transparent quality lower than 96x2 kbits for two stereo channels.