US 9,521,502 B2 · Method for determining a stereo signal

A method for determining an output stereo signal based on an input stereo signal, the input stereo signal comprising a first input audio channel signal and a second input audio channel signal, the method comprising:

determining a first differential signal based on a difference of the first input audio channel signal and a filtered version of the second input audio channel signal, and determining a second differential signal based on a difference of the second input audio channel signal and a filtered version of the first input audio channel signal;
determining a first power spectrum based on the first differential signal and determining a second power spectrum based on the second differential signal;
determining a first weighting function and a second weighting function as a function of the first power spectrum and the second power spectrum, wherein the first weighting function and the second weighting function comprise an exponential function;
and
filtering a first signal, which represents a first combination of the first input audio channel signal and the second input audio channel signal, with the first weighting function to obtain a first output audio channel signal of the output stereo signal, and filtering a second signal, which represents a second combination of the first input audio channel signal and the second input audio channel signal, with the second weighting function to obtain a second output audio channel signal of the output stereo signal,
wherein an exponent of the exponential function lies between 0.5 and 2.

3 more elements

A method for determining an output stereo signal based on an input stereo signal, the input stereo signal comprising a first input audio channel signal and a second input audio channel signal, the method comprising:

determining a first differential signal based on a difference of the first input audio channel signal and a filtered version of the second input audio channel signal, and determining a second differential signal based on a difference of the second input audio channel signal and a filtered version of the first input audio channel signal;
determining a first power spectrum based on the first differential signal and determining a second power spectrum based on the second differential signal;
determining a first weighting function and a second weighting function as a function of the first power spectrum and the second power spectrum, wherein the first weighting function and the second weighting function comprise an exponential function;
and
filtering a first signal, which represents a first combination of the first input audio channel signal and the second input audio channel signal, with the first weighting function to obtain a first output audio channel signal of the output stereo signal, and filtering a second signal, which represents a second combination of the first input audio channel signal and the second input audio channel signal, with the second weighting function to obtain a second output audio channel signal of the output stereo signal,
wherein determining the first and the second weighting function comprises:
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or comprises:
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where P1(k,i) denotes the first power spectrum, P2(k,i) denotes the second power spectrum, W1(k,i) denotes the weighting function with respect to the first power spectrum, W2(k,i) denotes the weighting function with respect to the second power spectrum, D(k,i) is a power spectrum of a diffuse sound determined as D(k,i)=Φ(k,i)min (P1(k,i),P2(k,i)), where Φ(k,i) is a normalized cross-correlation between the first and the second differential signals, g is a gain factor, β is an exponent of the exponential function, k is a time index and i is a frequency index.

187 more elements

An apparatus for determining an output stereo signal based on an input stereo signal, the input stereo signal comprising a first input audio channel signal and a second input audio channel signal, the apparatus comprising a processor for generating the output stereo signal from the first input audio channel signal and the second input audio channel signal by applying a method, wherein the method is for determining an output stereo signal based on an input stereo signal, wherein the input stereo signal comprises a first input audio channel signal and a second input audio channel signal, and wherein the method comprises:

determining a first differential signal based on a difference of the first input audio channel signal and a filtered version of the second input audio channel signal, and determining a second differential signal based on a difference of the second input audio channel signal and a filtered version of the first input audio channel signal;
determining a first power spectrum based on the first differential signal and determining a second power spectrum based on the second differential signal;
determining a first weighting function and a second weighting function as a function of the first power spectrum and the second power spectrum, wherein the first weighting function and the second weighting function comprise an exponential function;
and
filtering a first signal, which represents a first combination of the first input audio channel signal and the second input audio channel signal, with the first weighting function to obtain a first output audio channel signal of the output stereo signal, and filtering a second signal, which represents a second combination of the first input audio channel signal and the second input audio channel signal, with the second weighting function to obtain a second output audio channel signal of the output stereo signal,
wherein the apparatus comprises:
a memory for storing a width control parameter controlling a width of the stereo signal, the width control parameter being used by the first weighting function for weighting the first power spectrum and by the second weighting function for weighting the second power spectrum;
and/or
a user interface for providing the width control parameter.

6 more elements

An apparatus for determining an output stereo signal based on an input stereo signal, the input stereo signal comprising a first input audio channel signal and a second input audio channel signal, the apparatus comprising a processor for generating the output stereo signal from the first input audio channel signal and the second input audio channel signal by applying a method, wherein the method is for determining an output stereo signal based on an input stereo signal, wherein the input stereo signal comprises a first input audio channel signal and a second input audio channel signal, and wherein the method comprises:

determining a first differential signal based on a difference of the first input audio channel signal and a filtered version of the second input audio channel signal, and determining a second differential signal based on a difference of the second input audio channel signal and a filtered version of the first input audio channel signal;
determining a first power spectrum based on the first differential signal and determining a second power spectrum based on the second differential signal;
determining a first weighting function and a second weighting function as a function of the first power spectrum and the second power spectrum, wherein the first weighting function and the second weighting function comprise an exponential function;
and
filtering a first signal, which represents a first combination of the first input audio channel signal and the second input audio channel signal, with the first weighting function to obtain a first output audio channel signal of the output stereo signal, and filtering a second signal, which represents a second combination of the first input audio channel signal and the second input audio channel signal, with the second weighting function to obtain a second output audio channel signal of the output stereo signal,
wherein the width control parameter is an exponent applied to the first and the second power spectra, the exponent lying in a range between 0.5 and 2.

3 more elements

Method for determining a stereo signal

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Method for determining a stereo signal

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Abstract

Claims15