Patent ID: 8682681

Claim:
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 plurality of previously decoded spectral values; wherein the arithmetic decoder is configured to acquire a plurality of context subregion values describing sub-regions of the context on the basis of previously decoded spectral values and to store said context subregion values; wherein the arithmetic decoder is configured to derive a numeric current context value associated with one or more spectral values to be decoded in dependence on the stored context subregion values; wherein the arithmetic decoder is configured to compute the norm of a vector formed by a plurality of previously decoded spectral values, in order to acquire a common context subregion value associated with the plurality of previously decoded spectral values; 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.