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

US8898068B2 · kind B2 · utility

Assignee

• Fraunhofer-Gesellschaft zur förderung der angewandten Forschung e.V. · DE

Inventors

• Vignesh Subbaraman · Erlangen, DE
• Guillaume Fuchs · Erlangen, DE
• Markus Multrus · Nuremberg, DE
• Nikolaus Rettelbach · Nuremberg, DE
• Oliver Weiss · Nuremberg, DE
• Marc Gayer · Erlangen, DE
• Patrick Warmbold · Emskirchen, DE
• Christian Griebel · Nuremberg, DE

Key dates

• Filing date: Jul 12, 2012
• Grant date: Nov 25, 2014
• Expiry date: Jul 12, 2032

Classification

• Technology area (CPC G): Physics
• CPC primary: G10L19/002
• WIPO field: Computer technology
• WIPO sector: Electrical engineering

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.