Audio encoder, audio decoder, method for encoding and audio information, method for decoding an audio information and computer program using a modification of a number representation of a numeric previous context value
First Claim
1. An audio decoder for providing a decoded audio information on the basis of an encoded audio information, the audio decoder comprising:
- an arithmetic decoder for providing a plurality of decoded spectral values on the basis of an arithmetically-encoded representation of the spectral values comprised in the encoded audio information; and
a frequency-domain-to-time-domain converter for providing a time-domain audio representation using the decoded spectral values, in order to acquire the decoded audio information;
wherein the arithmetic decoder is configured to select a mapping rule describing a mapping of a code value of the arithmetically-encoded representation of spectral values onto a symbol code representing one or more of the decoded spectral values or at least a portion of one or more of the decoded spectral values in dependence on a context state described by a numeric current context value; and
wherein the arithmetic decoder is configured to determine the numeric current context value in dependence on a numeric previous context value and in dependence on a plurality of previously-decoded spectral values,wherein the arithmetic decoder is configured to modify a number representation of the numeric previous context value, describing a context state for the decoding of one or more previously decoded spectral values, in dependence on a context subregion value describing a subregion of a context, to acquire a number representation of a numeric current context value describing a context state for the decoding of one or more spectral values to be decoded,wherein correlations between the numeric previous context value and the numeric current context value are exploited;
wherein the audio decoder is implemented using a hardware apparatus, or using a computer, or using a combination of a hardware apparatus and a computer.
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Abstract
An audio decoder includes an arithmetic decoder for providing decoded spectral values on the basis of an arithmetically-encoded representation of the spectral values and a frequency-domain-to-time-domain converter for providing a time-domain audio representation using the decoded spectral values. The arithmetic decoder selects a mapping rule describing a mapping of a code value onto a symbol code in dependence on a context state described by a numeric current context value, and determines the numeric current context value in dependence on a plurality of previously-decoded spectral values. The arithmetic decoder modifies a number representation of a numeric previous context value, describing a context state associated with one or more previously decoded spectral values, in dependence on a context subregion value, to acquire a number representation of a numeric current context value describing a context state associated with one or more spectral values to be decoded. An audio encoder uses a similar concept.
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Citations
26 Claims
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1. An audio decoder for providing a decoded audio information on the basis of an encoded audio information, the audio decoder comprising:
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an arithmetic decoder for providing a plurality of decoded spectral values on the basis of an arithmetically-encoded representation of the spectral values comprised in the encoded audio information; and a frequency-domain-to-time-domain converter for providing a time-domain audio representation using the decoded spectral values, in order to acquire the decoded audio information; wherein the arithmetic decoder is configured to select a mapping rule describing a mapping of a code value of the arithmetically-encoded representation of spectral values onto a symbol code representing one or more of the decoded spectral values or at least a portion of one or more of the decoded spectral values in dependence on a context state described by a numeric current context value; and wherein the arithmetic decoder is configured to determine the numeric current context value in dependence on a numeric previous context value and in dependence on a plurality of previously-decoded spectral values, wherein the arithmetic decoder is configured to modify a number representation of the numeric previous context value, describing a context state for the decoding of one or more previously decoded spectral values, in dependence on a context subregion value describing a subregion of a context, to acquire a number representation of a numeric current context value describing a context state for the decoding of one or more spectral values to be decoded, wherein correlations between the numeric previous context value and the numeric current context value are exploited; wherein the audio decoder is implemented using a hardware apparatus, or using a computer, or using a combination of a hardware apparatus and a computer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. An audio encoder for providing an encoded audio information on the basis of an input audio information, the audio encoder comprising:
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an energy-compacting time-domain-to-frequency-domain converter for providing a frequency-domain audio representation on the basis of a time-domain representation of the input audio information, such that the frequency-domain audio representation comprises a set of spectral values; and an arithmetic encoder configured to encode a spectral value or a preprocessed version thereof, using a variable length codeword, wherein the arithmetic encoder is configured to map one or more spectral values, or a value of a most significant bitplane of one or more spectral values, onto a code value, wherein the encoded audio information comprises a plurality of variable length codewords, wherein the arithmetic encoder is configured to select a mapping rule describing a mapping of one or more spectral values, or of a value of a most significant bitplane of one or more spectral values, onto a code value in dependence on a context state described by a numeric current context value; and wherein the arithmetic encoder is configured to determine the numeric current context value in dependence on a numeric previous context value and in dependence on a plurality of previously-encoded spectral values, wherein the arithmetic encoder is configured to modify a number representation of the numeric previous context value, describing a context state for the encoding of one or more previously-encoded spectral values, in dependence on a context subregion value describing a subregion of a context, to acquire a number representation of a numeric current context value describing a context state for the encoding of one or more spectral values to be encoded; wherein correlations between the numeric previous context value and the numeric current context value are exploited; wherein the audio encoder is implemented using a hardware apparatus, or using a computer, or using a combination of a hardware apparatus and a computer.
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17. A method for providing a decoded audio information on the basis of an encoded audio information, the method comprising:
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providing a plurality of decoded spectral values on the basis of an arithmetically-encoded representation of the spectral values comprised in the encoded audio information; and providing a time-domain audio representation using the decoded spectral values, in order to acquire the decoded audio information; wherein providing the plurality of decoded spectral values comprises selecting a mapping rule describing a mapping of a code value of the arithmetically encoded representation of spectral values onto a symbol code representing one or more of the decoded spectral values, or at least a portion of one or more of the decoded spectral values in dependence on a context state described by a numeric current context value; and wherein the numeric current context value is determined in dependence on a numeric previous context value and in dependence on a plurality of previously decoded spectral values, wherein a number representation of the numeric previous context value, describing a context state for the decoding of one or more previously decoded spectral values, is modified in dependence on a context subregion value describing a subregion of a context, to acquire a number representation of a numeric current context value, describing a context state for the decoding of one or more spectral values to be decoded; wherein correlations between the numeric previous context value and the numeric current context value are exploited; wherein the method is performed using a hardware apparatus, or using a computer, or using a combination of a hardware apparatus and a computer. - View Dependent Claims (19)
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18. A method for providing an encoded audio information on the basis of an input audio information, the method comprising:
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providing a frequency-domain audio representation on the basis of a time-domain representation of the input audio information using an energy-compacting time-domain-to-frequency-domain conversion, such that the frequency-domain audio representation comprises a set of spectral values; and arithmetically encoding a spectral value, or a preprocessed version thereof, using a variable-length codeword, wherein a spectral value or a value of a most significant bitplane of a spectral value is mapped onto a code value; wherein a mapping rule describing a mapping of one or more spectral values, or of a most significant bitplane of one or more spectral values, onto a code value is selected in dependence on a context state described by a numeric current context value; and wherein the numeric current context value is determined in dependence on a numeric previous context value and in dependence on a plurality of previously-encoded spectral values; wherein a number representation of the numeric previous context value, describing a context state for the encoding of one or more previously encoded spectral values, is modified in dependence on a context subregion value describing a subregion of a context, to acquire a number representation of a numeric current context value describing a context state for the encoding of one or more spectral values to be encoded; wherein the encoded audio information comprises a plurality of variable-length codewords; wherein correlations between the numeric previous context value and the numeric current context value are exploited; wherein the method is performed using a hardware apparatus, or using a computer, or using a combination of a hardware apparatus and a computer. - View Dependent Claims (20)
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21. An audio decoder for providing a decoded audio information on the basis of an encoded audio information, the audio decoder comprising:
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an arithmetic decoder for providing a plurality of decoded spectral values on the basis of an arithmetically-encoded representation of the spectral values comprised in the encoded audio information; and a frequency-domain-to-time-domain converter for providing a time-domain audio representation using the decoded spectral values, in order to acquire the decoded audio information; wherein the arithmetic decoder is configured to select a mapping rule describing a mapping of a code value of the arithmetically-encoded representation of spectral values onto a symbol code representing one or more of the decoded spectral values or at least a portion of one or more of the decoded spectral values in dependence on a context state described by a numeric current context value; and wherein the arithmetic decoder is configured to determine the numeric current context value in dependence on a numeric previous context value and in dependence on a plurality of previously-decoded spectral values, wherein the arithmetic decoder is configured to modify a number representation of the numeric previous context value, describing a context state for the decoding of one or more previously decoded spectral values, in dependence on a context subregion value describing a subregion of a context, to acquire a number representation of a numeric current context value describing a context state for the decoding of one or more spectral values to be decoded, wherein at least a portion of a number representation of the numeric previous context value is maintained; wherein the audio decoder is implemented using a hardware apparatus, or using a computer, or using a combination of a hardware apparatus and a computer.
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22. An audio encoder for providing an encoded audio information on the basis of an input audio information, the audio encoder comprising:
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an energy-compacting time-domain-to-frequency-domain converter for providing a frequency-domain audio representation on the basis of a time-domain representation of the input audio information, such that the frequency-domain audio representation comprises a set of spectral values; and an arithmetic encoder configured to encode a spectral value or a preprocessed version thereof, using a variable length codeword, wherein the arithmetic encoder is configured to map one or more spectral values, or a value of a most significant bitplane of one or more spectral values, onto a code value, wherein the encoded audio information comprises a plurality of variable length codewords, wherein the arithmetic encoder is configured to select a mapping rule describing a mapping of one or more spectral values, or of a value of a most significant bitplane of one or more spectral values, onto a code value in dependence on a context state described by a numeric current context value; and wherein the arithmetic encoder is configured to determine the numeric current context value in dependence on a numeric previous context value and in dependence on a plurality of previously-encoded spectral values, wherein the arithmetic encoder is configured to modify a number representation of the numeric previous context value, describing a context state for the encoding of one or more previously-encoded spectral values, in dependence on a context subregion value describing a subregion of a context, to acquire a number representation of a numeric current context value describing a context state for the encoding of one or more spectral values to be encoded; wherein at least a portion of a number representation of the numeric previous context value is maintained; wherein the audio encoder is implemented using a hardware apparatus, or using a computer, or using a combination of a hardware apparatus and a computer.
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23. A method for providing a decoded audio information on the basis of an encoded audio information, the method comprising:
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providing a plurality of decoded spectral values on the basis of an arithmetically-encoded representation of the spectral values comprised in the encoded audio information; and providing a time-domain audio representation using the decoded spectral values, in order to acquire the decoded audio information; wherein providing the plurality of decoded spectral values comprises selecting a mapping rule describing a mapping of a code value of the arithmetically encoded representation of spectral values onto a symbol code representing one or more of the decoded spectral values, or at least a portion of one or more of the decoded spectral values in dependence on a context state described by a numeric current context value; and wherein the numeric current context value is determined in dependence on a numeric previous context value and in dependence on a plurality of previously decoded spectral values, wherein a number representation of the numeric previous context value, describing a context state for the decoding of one or more previously decoded spectral values, is modified in dependence on a context subregion value describing a subregion of a context, to acquire a number representation of a numeric current context value, describing a context state for the decoding of one or more spectral values to be decoded; wherein at least a portion of a number representation of the numeric previous context value is maintained; wherein the method is performed using a hardware apparatus, or using a computer, or using a combination of a hardware apparatus and a computer. - View Dependent Claims (25)
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24. A method for providing an encoded audio information on the basis of an input audio information, the method comprising:
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providing a frequency-domain audio representation on the basis of a time-domain representation of the input audio information using an energy-compacting time-domain-to-frequency-domain conversion, such that the frequency-domain audio representation comprises a set of spectral values; and arithmetically encoding a spectral value, or a preprocessed version thereof, using a variable-length codeword, wherein a spectral value or a value of a most significant bitplane of a spectral value is mapped onto a code value; wherein a mapping rule describing a mapping of one or more spectral values, or of a most significant bitplane of one or more spectral values, onto a code value is selected in dependence on a context state described by a numeric current context value; and wherein the numeric current context value is determined in dependence on a numeric previous context value and in dependence on a plurality of previously-encoded spectral values; wherein a number representation of the numeric previous context value, describing a context state for the encoding of one or more previously encoded spectral values, is modified in dependence on a context subregion value describing a subregion of a context, to acquire a number representation of a numeric current context value describing a context state for the encoding of one or more spectral values to be encoded; wherein the encoded audio information comprises a plurality of variable-length codewords; wherein at least a portion of a number representation of the numeric previous context value is maintained; wherein the method is performed using a hardware apparatus, or using a computer, or using a combination of a hardware apparatus and a computer. - View Dependent Claims (26)
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Specification