Reconstructing an audio signal having a baseband and high frequency components above the baseband
First Claim
1. An audio decoder for reconstructing an original audio signal having a baseband up to a cutoff frequency and high-frequency components not included in the baseband above the cutoff frequency, the audio decoder comprising:
- a bitstream deformatter that extracts a representation of the baseband, an estimated spectral envelope, and noise-blending parameters from an audio bitstream, wherein the representation of the baseband is a frequency domain representation that includes baseband spectral components, and wherein the cutoff frequency is capable of being varied dynamically;
a spectral component regenerator that copies or translates all or at least some of the baseband spectral components to non-overlapping frequency ranges of the high-frequency components not included in the baseband to generate regenerated spectral components;
a gain adjuster that modifies a spectral envelope of the regenerated spectral components based at least in part on the estimated spectral envelope and the noise-blending parameters to generate gain-adjusted regenerated spectral components, wherein the noise-blending parameters include a noise parameter for each of a plurality of frequency bands above the cutoff frequency; and
a synthesis filterbank that;
combines a frequency domain representation of the baseband with the gain-adjusted regenerated spectral components to form a frequency-domain representation of a reconstructed audio signal, andtransforms the frequency-domain representation of the reconstructed audio signal into a time domain,wherein the audio decoder comprises one or more hardware elements.
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Abstract
A method and system for reconstructing an original audio signal is disclosed. The original audio signal has a baseband up to a cutoff frequency and high-frequency components not included in the baseband above the cutoff frequency. The system includes a bitstream deformatter that extracts a representation of the baseband, an estimated spectral envelope, and noise-blending parameters from an audio bitstream. The system also includes a spectral component regenerator that copies or translates all or at least some of the baseband spectral components to non-overlapping frequency ranges of the high-frequency components not included in the baseband to generate regenerated spectral components. The system further includes a gain adjuster that modifies a spectral envelope of the regenerated spectral components based at least in part on the estimated spectral envelope and the noise-blending parameters to generate gain-adjusted regenerated spectral components.
79 Citations
9 Claims
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1. An audio decoder for reconstructing an original audio signal having a baseband up to a cutoff frequency and high-frequency components not included in the baseband above the cutoff frequency, the audio decoder comprising:
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a bitstream deformatter that extracts a representation of the baseband, an estimated spectral envelope, and noise-blending parameters from an audio bitstream, wherein the representation of the baseband is a frequency domain representation that includes baseband spectral components, and wherein the cutoff frequency is capable of being varied dynamically; a spectral component regenerator that copies or translates all or at least some of the baseband spectral components to non-overlapping frequency ranges of the high-frequency components not included in the baseband to generate regenerated spectral components; a gain adjuster that modifies a spectral envelope of the regenerated spectral components based at least in part on the estimated spectral envelope and the noise-blending parameters to generate gain-adjusted regenerated spectral components, wherein the noise-blending parameters include a noise parameter for each of a plurality of frequency bands above the cutoff frequency; and a synthesis filterbank that; combines a frequency domain representation of the baseband with the gain-adjusted regenerated spectral components to form a frequency-domain representation of a reconstructed audio signal, and transforms the frequency-domain representation of the reconstructed audio signal into a time domain, wherein the audio decoder comprises one or more hardware elements. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for reconstructing an original audio signal having a baseband up to a cutoff frequency and high-frequency components not included in the baseband above the cutoff frequency, the method comprising:
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extracting a representation of the baseband, an estimated spectral envelope, and noise-blending parameters from an audio bitstream, wherein the representation of the baseband is a frequency domain representation that includes baseband spectral components, and wherein the cutoff frequency is capable of being varied dynamically; copying or translating all or at least some of the baseband spectral components to non-overlapping frequency ranges of the high-frequency components not included in the baseband to generate regenerated spectral components; modifying a spectral envelope of the regenerated spectral components based at least in part on the estimated spectral envelope and the noise-blending parameters to generate gain-adjusted regenerated spectral components, wherein the noise-blending parameters include a noise parameter for each of a plurality of frequency bands above the cutoff frequency; combining a frequency domain representation of the baseband with the gain-adjusted regenerated spectral components to form a frequency-domain representation of a reconstructed audio signal; and transforming the frequency-domain representation of the reconstructed audio signal into a time domain, wherein the method is implemented with one or more hardware elements.
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Specification