Noise filling concept
First Claim
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1. An apparatus configured to perform a method, comprising:
- performing noise filling on a spectrum of an audio signal in a manner dependent on a tonality of the audio signal by filling a contiguous spectral zero-portion of the audio signal'"'"'s spectrum with noise spectrally shaped by one of;
using a function assuming a maximum in an inner of the contiguous spectral zero-portion, and comprising outwardly falling edges and setting an absolute slope of the function'"'"'s outwardly falling edges negatively depending on the tonality,using a function assuming a maximum in an inner of the contiguous spectral zero-portion, and comprising outwardly falling edges and setting a spectral width of the function positively depending on the tonality, andusing a unimodal function having a local maximum surrounded by two outwardly falling flanks and adjusting the unimodal function depending on the tonality such that an integral of the unimodal function, normalized to an integral of 1, over outer quarters of the contiguous spectral zero-portion negatively depends on the tonality; and
dequantizing the spectrum, as derived by the noise-filling, usinga spectrally varying and signal-adaptive quantization step size controlled via a linear prediction spectral envelope signaled via linear prediction coefficients in a data stream into which the spectrum is coded, orscale factors relating to scale factor bands, signaled in the data stream into which the spectrum is coded;
wherein the apparatus comprises any of a microprocessor, an electronic circuit, or a programmable computer.
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Abstract
Noise filling of a spectrum of an audio signal is improved in quality with respect to the noise filled spectrum so that the reproduction of the noise filled audio signal is less annoying, by performing the noise filling in a manner dependent on a tonality of the audio signal.
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Citations
23 Claims
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1. An apparatus configured to perform a method, comprising:
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performing noise filling on a spectrum of an audio signal in a manner dependent on a tonality of the audio signal by filling a contiguous spectral zero-portion of the audio signal'"'"'s spectrum with noise spectrally shaped by one of; using a function assuming a maximum in an inner of the contiguous spectral zero-portion, and comprising outwardly falling edges and setting an absolute slope of the function'"'"'s outwardly falling edges negatively depending on the tonality, using a function assuming a maximum in an inner of the contiguous spectral zero-portion, and comprising outwardly falling edges and setting a spectral width of the function positively depending on the tonality, and using a unimodal function having a local maximum surrounded by two outwardly falling flanks and adjusting the unimodal function depending on the tonality such that an integral of the unimodal function, normalized to an integral of 1, over outer quarters of the contiguous spectral zero-portion negatively depends on the tonality; and dequantizing the spectrum, as derived by the noise-filling, using a spectrally varying and signal-adaptive quantization step size controlled via a linear prediction spectral envelope signaled via linear prediction coefficients in a data stream into which the spectrum is coded, or scale factors relating to scale factor bands, signaled in the data stream into which the spectrum is coded; wherein the apparatus comprises any of a microprocessor, an electronic circuit, or a programmable computer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. Audio encoder configured to perform a method for noise filling, the method comprising:
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quantizing and coding a spectrum of an audio signal into a data stream; setting and coding into the data stream, a spectrally global noise filling level for performing noise filling on the spectrum of the audio signal, by spectrally shaping, dependent on the tonality of the audio signal, contiguous spectral zero-portions of the audio signal'"'"'s spectrum by one of; using a function assuming a maximum in an inner of the contiguous spectral zero-portion, and comprising outwardly falling edges and setting an absolute slope of the function'"'"'s outwardly falling edges negatively depending on the tonality, using a function assuming a maximum in an inner of the contiguous spectral zero-portion, and comprising outwardly falling edges and setting a spectral width of the function positively depending on the tonality, and using a unimodal function having a local maximum surrounded by two outwardly falling flanks and adjusting the unimodal function depending on the tonality such that an integral of the unimodal function, normalized to an integral of 1, over outer quarters of the contiguous spectral zero-portion negatively depends on the tonality, and tonality; and measuring a level of the audio signal within the contiguous spectral zero-portions of the spectrum having been spectrally shaped dependent on the tonality of the audio signal; wherein the audio encoder comprises any of a microprocessor, an electronic circuit, or a programmable computer. - View Dependent Claims (15, 16, 17, 18)
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19. Method comprising:
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performing noise filling on a spectrum of an audio signal in a manner dependent on a tonality of the audio signal by filling a contiguous spectral zero-portion of the audio signal'"'"'s spectrum with noise spectrally shaped by one of; using a function assuming a maximum in an inner of the contiguous spectral zero-portion, and comprising outwardly falling edges and setting an absolute slope of the function'"'"'s outwardly falling edges negatively depending on the tonality, using a function assuming a maximum in an inner of the contiguous spectral zero-portion, and comprising outwardly falling edges and setting a spectral width of the function positively depending on the tonality, and using a unimodal function having a local maximum surrounded by two outwardly falling flanks and adjusting the unimodal function depending on the tonality such that an integral of the unimodal function, normalized to an integral of 1, over outer quarters of the contiguous spectral zero-portion negatively depending on the tonality; and dequantizing the spectrum, as derived by the noise-filling, using; a spectrally varying and signal-adaptive quantization step size controlled via a linear prediction spectral envelope signaled via linear prediction coefficients in a data stream into which the spectrum is coded, or scale factors relating to scale factor bands, signaled in the data stream into which the spectrum is coded. - View Dependent Claims (21)
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20. Method for audio encoding supporting noise filling, the method comprising:
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quantizing and coding a spectrum of an audio signal into a data stream; setting and coding into the data stream, a spectrally global noise filling level for performing noise filling on the spectrum of the audio signal, by; spectrally shaping, dependent on the tonality of the audio signal, contiguous spectral zero-portions of the audio signal'"'"'s spectrum by one of; using a function assuming a maximum in an inner of the contiguous spectral zero-portion, and comprising outwardly falling edges and setting an absolute slope of the function'"'"'s outwardly falling edges negatively depending on the tonality, using a function assuming a maximum in an inner of the contiguous spectral zero-portion, and comprising outwardly falling edges and setting a spectral width of the function positively depending on the tonality, and using a unimodal function having a local maximum surrounded by two outwardly falling flanks and adjusting the unimodal function depending on the tonality such that an integral of the unimodal function, normalized to an integral of 1, over outer quarters of the contiguous spectral zero-portion negatively depends on the tonality; and measuring of a level of the audio signal within the contiguous spectral zero-portions of the spectrum having been spectrally shaped dependent on the tonality of the audio signal. - View Dependent Claims (22, 23)
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Specification