A review of algorithms for perceptual coding of digital audio signals

Abstract

During the last decade, CD-quality digital audio has essentially replaced analog audio. During this same period, new digital audio applications have emerged for network, wireless, and multimedia computing systems which face such constraints as reduced channel bandwidth, limited storage capacity, and low cost. These new applications have creuted(1 demand for high-quality digital audio delivery at low bit rates. In response to this need, considerable research has been devoted to the development of algorithmsfor perceptually transparent coding of high-fidelity (CD-quality) digital audio. As a result, many algorithms have been proposed, and several have now become international and/or commercicil product standards. This paper reviews algorithms for perceptually transparent coding of CD-quality digital audio, including both research and standardization activities. The paper is organized as follows. First, psychoacoustic principles are described with the MPEG psychoacoustic signal analysis model 1 discussed in some detail. Then, we review methodologies which achieve perceptually transparent coding of FM-and CD-quality audio signals, including algorithms which manipulate transform components and subband signal decompositions. The discussion concentrates on architectures and applications of irhose techniques which utilize psychoacoustic models to exploit efficiently masking characteristics of the human receiver. Several algorithms which have become international andlor commercial standards are also presented, including the ISO/MPEG family and the Dolby AC-3 algorithms. The paper concludes with a brief discussion of future research divect i o m

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