Audio encoder, audio decoder and related methods for processing multi-channel audio signals using complex prediction

US8655670B2 · kind B2 · utility

Assignees

• Fraunhofer-Gesellschaft zur förderung der angewandten Forschung e.V. · DE
• Dolby International AB · IE

Inventors

• Heiko Purnhagen · Sundbyberg, SE
• Pontus Carlsson · Bromma, SE
• Lars Villemoes · Stockholm, SE
• Julien Robillard · Nuremberg, DE
• Matthias Neusinger · Meiningen, DE
• Christian Helmrich · Erlangen, DE
• Johannes Hilpert · Nuremberg, DE
• Nikolaus Rettelbach · Nuremberg, DE
• Sascha Disch · Bad Mergentheim, DE
• Bernd Edler · Hannover, DE

Key dates

• Filing date: Oct 5, 2012
• Grant date: Feb 18, 2014
• Expiry date: Oct 5, 2032

Classification

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

Abstract

An encoder, based on a combination of two audio channels, obtains a first combination signal as a mid-signal and a residual signal derivable using a predicted side signal derived from the mid signal. The first combination signal and the prediction residual signal are encoded and written into a data stream together with the prediction information. A decoder generates decoded first and second channel signals using the prediction residual signal, the first combination signal and the prediction information. A real-to-imaginary transform may be applied for estimating the imaginary part of the spectrum of the first combination signal. For calculating the prediction signal used in the derivation of the prediction residual signal, the real-valued first combination signal is multiplied by a real portion of the complex prediction information and the estimated imaginary part of the first combination signal is multiplied by an imaginary portion of the complex prediction information.