Patent ID: 9633664
Date: 2017-04-25
CPC Classifications: G10L

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.