Koninklijke Philips Corporation N.v.

Fraunhofer-gesellschaft Zur Foerderung Der Angewandten Forschung E.v.

Coding Technologies Ab

Dolby International Ab

Dolby Sweden Ab

Koninklijke Philips International N.v.

Erik Schuijers

Heiko Purnhagen

Jonas Engdegard

Jeroen Dirk Breebaart

Lars Villemoes

Jürgen Herre

Werner Oomen

Sascha Disch

Matthias Neusinger

Kristofer Kjörling

Jonas Roeden

Jonas Röden

Kristofer Kjoerling

Juergen Herre

Johannes Hilpert

Ingrid Christina Maria Flinsenberg

Andreas Hölzer

Steven Van De Par

Jeroen Breebaart

A parametric representation of a multi-channel audio signal having parameters suited to be used together with a monophonic downmix signal to calculate a reconstruction of the multi-channel audio signal can efficiently be derived in a stereo-backwards compatible way when a parameter combiner is used to generate the parametric representation by combining a one or more spatial parameters and a stereo parameter resulting in a parametric representation having a decoder usable stereo parameter and an information on the one or more spatial parameters that represents, together with the decoder usable stereo parameter, the one or more spatial parameters.

Stereo compatible multi-channel audio coding

An apparatus and a method for generating a multi-channel synthesizer control signal, a multi-channel synthesizer, a method of generating an output signal from an input signal and a machine-readable storage medium are provided. On an encoder-side, a multi-channel input signal is analyzed for obtaining smoothing control information, which is to be used by a decoder-side multi-channel synthesis for smoothing quantized transmitted parameters or values derived from the quantized transmitted parameters for providing an improved subjective audio quality in particular for slowly moving point sources and rapidly moving point sources having tonal material such as fast moving sinusoids.

Apparatus and method for generating a multi-channel synthesizer control signal, multi-channel synthesizer, method of generating an output signal from an input signal and machine-readable storage medium

An audio decoder comprises a receiver () for receiving input data comprising an N-channel signal corresponding to a down-mixed signal of an M-channel audio signal, M&#x3e;N, having complex valued subband encoding matrices applied in frequency subbands and parametric multi-channel data. A subband filter bank () generates real-valued frequency subbands for the N-channel signal. A matrix processor () determines real-valued subband decoding matrices for compensating the application of the encoding matrices in response to the parametric multi-channel data. A compensation processor () generates down-mix data corresponding to the down-mixed signal by a matrix multiplication of the real-valued subband decoding matrices and data of the N-channel signal in the at least some real-valued frequency subbands. The down-mix data can be used to regenerate the down-mixed signal and the M-channel audio signal. The decoder may compensate for MPEG Matrix Surround Compatibility operations performed at the encoder using real-valued frequency subbands.

Audio decoding

Parameters being a measure for a characteristic of a channel or of a pair of channels, wherein the parameter is a measure for a characteristic of the channel or of the pair of channels with respect to another channel of a multi-channel signal can be quantized more efficiently using a quantization rule that is generated based on a relation of an energy measure of the channel or the pair of channels and an energy measure of the multi-channel signal. With generation of the quantization rule taking into account a psycho acoustic approach, the size of an encoded representation of the multi-channel signal can be decreased by coarser quantization without significantly disturbing the perceptual quality of the multi-channel signal when reconstructed from the encoded representation.

Energy dependent quantization for efficient coding of spatial audio parameters

A multi-channel signal having at least three channels can be reconstructed such, that the reconstructed channels are at least partly de-correlated from each other using a downmixed signal derived from an original multi-channel signal and a set of de-correlated signals provided by a de-correlator () that derives the set of de-correlated signals from the down-mix signal, wherein the de-correlated signals within the set of de-correlated signals are mutually mostly orthogonal to each other, i.e. an orthogonality relation between channel pairs is satisfied within an orthogonality tolerance range.

Audio coding using de-correlated signals

On an encoder-side, a multi-channel input signal is analyzed for obtaining smoothing control information, which is to be used by a decoder-side multi-channel synthesis for smoothing quantized transmitted parameters or values derived from the quantized transmitted parameters for providing an improved subjective audio quality in particular for slowly moving point sources and rapidly moving point sources having tonal material such as fast moving sinusoids.

Apparatus and method for generating multi-channel synthesizer control signal and apparatus and method for multi-channel synthesizing

A parametric representation of a multi-channel audio signal describes the spatial properties of the audio signal well with compact side information when a coherence information, describing the coherence between a first and a second channel, is derived within a hierarchical encoding process only for channel pairs including a first channel having only information of a left side with respect to a listening position and including a second channel having only information from a right side with respect to a listening position. As within the hierarchical process the multiple audio channels of the audio signal are downmixed iteratively into monophonic channels, one can pick the relevant parameters from an encoding step involving only channel pairs carrying the information needed to describe the spatial properties of the multi-channel audio signal.

Multi-channel hierarchical audio coding with compact side information

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Eindhoven, Netherlands

Erik Schuijers