A Nonlinear Psychoacoustic Model Applied to ISO/MPEG Layer 3 Coder

Abstract

A psychoacoustic model which approximates the masked threshold evoked by complex sounds is presented. It features nonlinear superposition of masking components in order to generate masked thresholds which closely match known psychoacoustic data. First results obtained with the psychoacoustic model for controlling the quantizers of the ISO MPEG Layer 3 coder are discussed. 1 Introduction Significant improvements of high quality audio bit rate reduction have been achieved by considering the properties of the human auditory perception. This is generally realized by the introduction of a psychoacoustic model which generates the masked threshold evoked by a sound signal and which controls the quantizers of a coding system. The masked threshold for quantization errors is defined as the maximum level of quantization noise which is just non audible in the presence of a masking sound. Therefore, the quantization noise will only become audible if the level exceeds the masked threshold. Bit rate...