DYNAMIC RANGE CONTROL WITH LARGE LOOK-AHEAD

摘要

A system and method applying Dynamic Range Control/Compression (DRC) to an audio signal. The dynamic range controller presented here differs from conventional DRC techniques by providing a much larger look-ahead time. In particular, the system and method takes advantage of the look-ahead by analyzing macroscopic loudness changes in the order of seconds as opposed to the microscopic changes most conventional DRCs are designed to control. This approach avoids most of the typical DRC distortions associated with conventional DRC techniques and preserves the micro-dynamics of the audio signal. Gain changes are applied at a rate comparable with manual volume adjustments by mixing and mastering engineers to balance a mix. Ideally, the DRC will approach what a professional sound engineer would do to reduce the dynamic range if there were only a volume control to accomplish the task on the final mix.

主权项

1. A method of performing dynamic range control (DRC) with a large look-ahead on an audio signal, comprising:
generating a loudness estimate for the audio signal; generating adaptive time constants by analyzing the loudness estimate during a predefined look-ahead time period; smoothing the loudness estimate using the adaptive time constants; generating DRC gain values to apply to a delayed version of the audio signal based on the smoothed loudness estimate; and applying the DRC gain values to the delayed audio signal.