Continuously signal-adaptive filterbank for high-quality perceptual audio coding

Abstract

Historically, the choice of the optimum filterbank has been the subject of much research and discussion in the development of perceptual audio coders. Desirable properties of a good filterbank include both a good extraction of the signal's redundancy and effective utilization of that redundancy while maintaining control over perceptual demands. Often, there is a conflict between the use of perceptual constraints and the redundancy extraction, in that a filterbank with good resolution in both time and frequency is needed. Recently, a method for performing temporal noise shaping (TNS) of the error signal of a perceptual audio coder has been proposed, providing control over both the time and frequency structure of the coding noise. This paper focuses on the core part of the scheme, forming a continuously adaptive filterbank, and discusses its theoretical background, properties and limitations.