Audio encoder, audio decoder, method for encoding and audio information, method for decoding an audio information and computer program using a hash table describing both significant state values and interval boundaries

US8645145B2 · 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
• Marc Gayer · Erlangen, DE
• Oliver Weiss · Nuremberg, DE
• Christian Griebel · Nuremberg, DE
• Patrick Warmbold · Emskirchen, DE

Key dates

• Filing date: Jul 12, 2012
• Grant date: Feb 4, 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 a plurality of 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. The arithmetic decoder determines the numeric current context value in dependence on a plurality of previously decoded spectral values. The arithmetic decoder evaluates a hash table, entries of which define both significant state values and boundaries of intervals of numeric context values, in order to select the mapping rule. A mapping rule index value is individually associated to a numeric context value being a significant state value.