DYNAMIC RANGE AND PEAK CONTROL IN AUDIO USING NONLINEAR FILTERS

摘要

An audio encoding device is described herein. The audio encoding device includes a compressor that is based on a nonlinear filter. In particular, the nonlinear filter may be selected from the class of edge-preserving smoothing filters, which avoids common artifacts of conventional compressors. Edge-preserving smoothing filters have been used in image processing algorithms for their de-noising properties while preserving edges in the image. These properties are useful for audio compression because macro-dynamic loudness changes can be tracked precisely while micro-dynamic loudness changes can be ignored for the compression. Due to these advantages, more aggressive compression can be achieved with less distortion.

主权项

1. A method for encoding an audio signal, comprising:
processing samples of the audio signal using a loudness model to determine the instantaneous loudness of the audio signal for a set of the samples; processing the instantaneous loudness using a primary nonlinear filter to generate a smoothed loudness; mapping the smoothed loudness to a dynamic range compression gain value; and combining the dynamic range compression gain value with the audio signal to generate a compressed audio signal.