Method and device for processing a stereo audio signal

US7260225B2 · kind B2 · utility

Assignee

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

Inventors

• Bodo Teichmann · Ergolding, DE
• Oliver Kunz · Seßlach, DE
• Juergen Herre · Erlangen, DE
• Klaus Peichl · Fürth, DE
• Michael Beer · Erlangen, DE

Key dates

• Filing date: Dec 7, 2000
• Grant date: Aug 21, 2007
• Expiry date: Nov 18, 2022

Classification

• Technology area (CPC G): Physics
• CPC primary: G10L19/008
• WIPO field: Audio-visual technology
• WIPO sector: Electrical engineering

Abstract

In a device for processing a stereo audio signal having a first channel and a second channel the stereo signal is at first analyzed to obtain a measure for a quantity of bits required by a coder to code the stereo audio signal using a coding algorithm. The first channel and the second channel are then modified when the measure for the quantity of bits is larger than a predetermined value, the modification being performed in such a way that the energy of a sum signal of the first and the second modified channel is in a predetermined relation to the energy of a sum signal of the first and the second channel and that a difference signal of the first and the second modified channel is attenuated in contrast to the difference signal of the first and the second channel. Especially for audio coders requiring a constant output bit rate the side channel is attenuated in the case of stereo audio signals, the coding of which cannot meet the output bit rate of the coder, by which a stereo channel separation is abandoned for the benefit of an increased audio bandwidth or a reduction of quantizing disturbances, respectively.