LINEAR PREDICTION BASED AUDIO CODING USING IMPROVED PROBABILITY DISTRIBUTION ESTIMATION
First Claim
1. A linear prediction based audio decoder comprising:
- a probability distribution estimator configured to determine, for each of a plurality of spectral components, a probability distribution estimation from linear prediction coefficient information comprised in a data stream into which an audio signal is encoded;
an entropy decoding and dequantization stage configured to entropy decode and dequantize a spectrum composed of the plurality of spectral components from the data stream using the probability distribution estimation as determined for each of the plurality of spectral components; and
a filter configured to shape the spectrum according to a transfer function depending on a linear prediction synthesis filter defined by the linear prediction coefficient information,wherein the probability distribution estimator is configured to determine a spectral fine structure from long-term prediction parameters comprised in the data stream and determine, for each of the plurality of spectral components, a probability distribution parameter such that the probability distribution parameters spectrally follow a function which multiplicatively depends on the spectral fine structure, wherein, for each of the plurality of spectral components, the probability distribution estimation is a parameterizable function parameterized with the probability distribution parameter of the respective spectral component.
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Abstract
Linear prediction based audio coding is improved by coding a spectrum composed of a plurality of spectral components using a probability distribution estimation determined for each of the plurality of spectral components from linear prediction coefficient information. The linear prediction coefficient information is available anyway. Accordingly, it may be used for determining the probability distribution estimation at both encoding and decoding side. The latter determination may be implemented in a computationally simple manner by using, for example, an appropriate parameterization for the probability distribution estimation at the plurality of spectral components. The coding efficiency as provided by the entropy coding is compatible with probability distribution estimations as achieved using context selection, but its derivation is less complex. The derivation may be purely analytically and/or does not require any information on attributes of neighboring spectral lines such as previously coded/decoded spectral values of neighboring spectral lines as is the case in spatial context selection.
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Citations
30 Claims
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1. A linear prediction based audio decoder comprising:
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a probability distribution estimator configured to determine, for each of a plurality of spectral components, a probability distribution estimation from linear prediction coefficient information comprised in a data stream into which an audio signal is encoded; an entropy decoding and dequantization stage configured to entropy decode and dequantize a spectrum composed of the plurality of spectral components from the data stream using the probability distribution estimation as determined for each of the plurality of spectral components; and a filter configured to shape the spectrum according to a transfer function depending on a linear prediction synthesis filter defined by the linear prediction coefficient information, wherein the probability distribution estimator is configured to determine a spectral fine structure from long-term prediction parameters comprised in the data stream and determine, for each of the plurality of spectral components, a probability distribution parameter such that the probability distribution parameters spectrally follow a function which multiplicatively depends on the spectral fine structure, wherein, for each of the plurality of spectral components, the probability distribution estimation is a parameterizable function parameterized with the probability distribution parameter of the respective spectral component. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A linear prediction based audio encoder comprising:
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a linear prediction analyzer configured to determine linear prediction coefficient information; a probability distribution estimator configured to determine, for each of a plurality of spectral components, a probability distribution estimation from the linear prediction coefficient information; and a spectrum determiner configured to determine a spectrum composed of the plurality of spectral components from an audio signal; a quantization and entropy encoding stage configured to quantize and entropy encode the spectrum using the probability distribution estimation as determined for each of the plurality of spectral components, wherein the spectrum determiner is configured to shape an original spectrum of the audio signal according to a transfer function which depends on an inverse of a linear prediction synthesis filter defined by the linear prediction coefficient information, and wherein the linear prediction based audio encoder further comprises a long-term predictor configured to determine long-term prediction parameters and the probability distribution estimator is configured to determine a spectral fine structure from the long-term prediction parameters and determine, for each of the plurality of spectral components, a probability distribution parameter such that the probability distribution parameters spectrally follow a function which depends on a product of a transfer function of the linear prediction synthesis filter, an inverse of a transfer function of a perceptually weighted modification of the linear prediction synthesis filter, and the spectral fine structure, wherein, for each of the plurality of spectral components, the probability distribution estimation is a parameterizable function parameterized with the probability distribution parameter of the respective spectral component. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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27. A method for linear prediction based audio decoding, comprising:
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determining, for each of a plurality of spectral components, a probability distribution estimation from linear prediction coefficient information comprised in a data stream into which an audio signal is encoded; and entropy decoding and dequantizing a spectrum composed of the plurality of spectral components from the data stream using the probability distribution estimation as determined for each of the plurality of spectral components, the method also comprising shaping the spectrum according to a transfer function depending on a linear prediction synthesis filter defined by the linear prediction coefficient information, wherein the determination of the probability distribution estimation comprises determining a spectral fine structure from long-term prediction parameters comprised in the data stream and determining, for each of the plurality of spectral components, a probability distribution parameter such that the probability distribution parameters spectrally follow a function which multiplicatively depends on the spectral fine structure, wherein, for each of the plurality of spectral components, the probability distribution estimation is a parameterizable function parameterized with the probability distribution parameter of the respective spectral component. - View Dependent Claims (29)
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28. A method for linear prediction based audio encoding, comprising:
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determining linear prediction coefficient information; determining, for each of a plurality of spectral components, a probability distribution estimation from the linear prediction coefficient information; and determining a spectrum composed of the plurality of spectral components from an audio signal; quantizing and entropy encoding the spectrum using the probability distribution estimation as determined for each of the plurality of spectral components, wherein the determination of the spectrum comprises shaping an original spectrum of the audio signal according to a transfer function which depends on an inverse of a linear prediction synthesis filter defined by the linear prediction coefficient information, and wherein the method further comprises determining long-term prediction parameters and the determination of the probability distribution comprises determining a spectral fine structure from the long-term prediction parameters and determining, for each of the plurality of spectral components, a probability distribution parameter such that the probability distribution parameters spectrally follow a function which depends on a product of a transfer function of the linear prediction synthesis filter, an inverse of a transfer function of a perceptually weighted modification of the linear prediction synthesis filter, and the spectral fine structure, wherein, for each of the plurality of spectral components, the probability distribution estimation is a parameterizable function parameterized with the probability distribution parameter of the respective spectral component. - View Dependent Claims (30)
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Specification