Audio encoder, audio decoder, method for encoding an audio information, method for decoding an audio information and computer program using an iterative interval size reduction

US8655669B2 · kind B2 · utility

Assignee

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

Inventors

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

Key dates

• Filing date: Apr 19, 2012
• Grant date: Feb 18, 2014
• Expiry date: Apr 19, 2032

Classification

• Technology area (CPC G): Physics
• CPC primary: G10L19/0208
• WIPO field: Computer technology
• WIPO sector: Electrical engineering

Abstract

An audio decoder has an arithmetic decoder for providing decoded spectral values on the basis of an arithmetically-encoded representation and a frequency-domain-to-time-domain converter for providing a time-domain audio representation. The arithmetic decoder selects a mapping rule describing a mapping of a code value onto a symbol code in dependence on a numeric current context value describing a current context state. The arithmetic decoder determines the numeric current context value in dependence on a plurality of previously decoded spectral values. The arithmetic decoder evaluates at least one table using an iterative interval size reduction to determine whether the numeric current context value is identical to a table context value described by an entry of the table or lies within an interval described by entries of the table, and derives a mapping rule index value describing a selected mapping table.An audio encoder also uses an iterative interval table size reduction.