Selective bandwidth extension for encoding/decoding audio/speech signal
First Claim
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1. A method of receiving an audio signal, the method comprising:
- measuring a periodicity of the audio signal to determine a checked periodicity;
if the checked periodicity of the audio signal is lower than a threshold, composing at least one extended subband in a frequency domain, wherein composing comprisesreducing a ratio of copied harmonic components to composed or copied noise components if the checked periodicity is lower than the threshold, andgenerating an extended fine spectral structure in the frequency domain based on adding the copied harmonic components and the composed or copied noise components of at least one subband; and
scaling a magnitude of the at least one extended subband based on a spectral envelope on the audio signal, wherein the steps of measuring, composing, reducing, generating and scaling are performed using a hardware-based audio decoder.
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Abstract
A method of receiving an audio signal includes measuring a periodicity of the audio signal to determine a checked periodicity. At least one best available subband is determined. At least one extended subband is composed, wherein composing includes reducing a ratio of composed harmonic components to composed noise components if the checked periodicity is lower than a threshold, and scaling a magnitude of the at least one extended subband based on a spectral envelope on the audio signal.
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Citations
27 Claims
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1. A method of receiving an audio signal, the method comprising:
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measuring a periodicity of the audio signal to determine a checked periodicity; if the checked periodicity of the audio signal is lower than a threshold, composing at least one extended subband in a frequency domain, wherein composing comprises reducing a ratio of copied harmonic components to composed or copied noise components if the checked periodicity is lower than the threshold, and generating an extended fine spectral structure in the frequency domain based on adding the copied harmonic components and the composed or copied noise components of at least one subband; and scaling a magnitude of the at least one extended subband based on a spectral envelope on the audio signal, wherein the steps of measuring, composing, reducing, generating and scaling are performed using a hardware-based audio decoder. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A method of decoding an encoded audio signal, the method comprising:
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dividing an available low band of the encoded audio signal into a plurality of available subbands; determining if each available subband comprises adequate harmonic content; selecting available subbands that have adequate harmonic content based on the determining; and composing an extended high band from copying the selected available subbands, wherein composing is performed in a frequency domain and the steps of dividing, determining, selecting and composing are performed using a hardware-based audio decoder. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22)
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23. A system for receiving an encoded audio signal, the system comprising:
a receiver configured to receive the encoded audio signal, the receiver comprising a hardware-based audio decoder configured to; measure a periodicity of the audio signal to determine a checked periodicity, and compose at least one extended subband in a frequency domain if the checked periodicity is lower than a threshold by reducing a ratio of copied harmonic components to composed or copied noise components of the least one extended subband, and scaling a magnitude of the at least one extended subband based on a spectral envelope of the audio signal to produce a scaled extended subband. - View Dependent Claims (24, 25, 26, 27)
Specification