Adaptive loudness control
First Claim
Patent Images
1. A method, comprising:
- receiving an input audio signal;
determining a signal energy of the input audio signal;
determining a band energy of the input audio signal for each of multiple frequency bands of the input audio signal;
converting each band energy to a corresponding band loudness to produce multiple band loudnesses;
summing the multiple band loudnesses to produce a signal loudness;
receiving a loudness value specified by a human listener, wherein the loudness value indicates a desired relative audio loudness;
multiplying the loudness value by a ratio of the signal loudness to the signal energy to produce a signal gain;
amplifying the input audio signal by the signal gain to produce an output audio signal; and
providing the output audio signal to a loudspeaker.
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Abstract
Loudness control is performed by estimating the energy and loudness of an audio signal. Loudness of the audio signal is determined by decomposing the audio signal into multiple frequency bands at different center frequencies. The energy of the audio signal in each frequency band is calculated and converted to a loudness, using a function that models human loudness perceptions of audio energies at different frequencies. The loudnesses are summed to obtain the total loudness of the audio signal. A signal gain is calculated as a function of a loudness setting provided by a human listener, the estimated signal energy, and the total loudness of the audio signal.
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Citations
19 Claims
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1. A method, comprising:
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receiving an input audio signal; determining a signal energy of the input audio signal; determining a band energy of the input audio signal for each of multiple frequency bands of the input audio signal; converting each band energy to a corresponding band loudness to produce multiple band loudnesses; summing the multiple band loudnesses to produce a signal loudness; receiving a loudness value specified by a human listener, wherein the loudness value indicates a desired relative audio loudness; multiplying the loudness value by a ratio of the signal loudness to the signal energy to produce a signal gain; amplifying the input audio signal by the signal gain to produce an output audio signal; and providing the output audio signal to a loudspeaker. - View Dependent Claims (2, 3, 4, 5)
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6. A device, comprising:
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one or more processors; computer-readable media storing instructions that are executable by the one or more processors to perform acts comprising; receiving an input audio signal; determining a signal energy of the input audio signal; analyzing the input audio signal at different frequencies of the input audio signal to determine a signal loudness; receiving an input signal specifying a loudness value; determining a signal gain based on the signal loudness and a product of the loudness value and the signal energy; and applying the signal gain to the input audio signal to produce an output audio signal. - View Dependent Claims (7, 8, 9, 10, 11, 12)
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13. A method, comprising:
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determining a signal energy of an input audio signal; analyzing the input audio signal to produce a signal loudness; determining a preliminary value of a signal gain as a function of the signal energy and the signal loudness, wherein the preliminary value of the signal gain is based at least in part on multiplying a loudness value by a ratio of the signal loudness to the signal energy; adjusting the signal gain by applying a function to consecutive values associated with the preliminary value; and applying the signal gain to the input audio signal to produce an output audio signal. - View Dependent Claims (14, 15, 16, 17, 18, 19)
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Specification