Patent ID: 9647624
Date: 2017-05-09
CPC Classifications: H03G

Claim:
1. A frequency-domain system for modifying an amplitude of an input digital audio signal, comprising: a frequency analysis module configured to segment the input digital audio signal into overlapping frames and to apply an analysis window to each frame, and configured to then convert each frame to the frequency domain; a peak loudness value estimation module configured to estimate a peak loudness value used to derive an adaptive gain for each frame; an automatic gain control module configured to compute a wideband gain based on the peak loudness values to provide an adjusted digital audio signal in the frequency domain; a frequency synthesis module configured to convert the adjusted digital audio signal to the time domain; an overlap-and-add module configured to apply a synthesis window to the adjusted digital audio signal in the time domain to provide an output digital audio signal; and a multi-band dynamic compressor module configured to separate each frame into signals for sub-bands, each sub-band including at least one frequency bin and the multi-band dynamic compressor module further configured to compute a multi-band gain to compress the signal of each sub-band at a faster speed than the automatic gain control nodule computes the wideband gain, and wherein the multi-band dynamic compressor module is further configured to compute the gain of each bin based on linear interpolation and to then provide linear phase low-pass finite impulse response filtering to generate a gain for each frequency bin.