Amazon.com, Inc.
Block-based audio limiter

Abstract:

A system configured to perform audio limiting using block-based processing to reduce acoustic distortion and/or computational cost. While sample-by-sample processing would apply a plurality of gain ramps to a single audio sample, the block-based processing applies a single gain ramp to ensure that the audio sample is below a threshold value. To perform block-based processing, an audio limiter component identifies a maximum amplitude value across all channels for a selected audio frame of an audio signal. Using the maximum amplitude value and the threshold value, the audio limiter component determines a block gain value associated with the selected audio frame and selects between attack processing, hold processing, or release processing. Using the selected processing and the block gain value, the audio limiter component determines instantaneous gain values for the audio samples within the audio frame.