Multi-channel audio decoder, multi-channel audio encoder, methods and computer program using a residual-signal-based adjustment of a contribution of a decorrelated signal

Patent metadata

Field	Value
Publication number	US-10839812-B2
Application number	US-201615004571-A
Country	US
Kind code	B2
Filing date	Jan 22, 2016
Priority date	Jul 22, 2013
Publication date	Nov 17, 2020
Grant date	Nov 17, 2020

Abstract

A multi-channel audio decoder for providing at least two output audio signals on the basis of an encoded representation is configured to perform a weighted combination of a downmix signal, a decorrelated signal and a residual signal, to obtain one of the output audio signals. The multi-channel audio decoder is configured to determine a weight describing a contribution of the decorrelated signal in the weighted combination in dependence on the residual signal. A multi-channel audio encoder for providing an encoded representation of a multi-channel audio signal is configured to obtain a downmix signal on the basis of the multi-channel audio signal, to provide parameters describing dependencies between the channels of the multi-channel audio signal, and to provide a residual signal. The multi-channel audio encoder is configured to vary an amount of residual signal included into the encoded representation in dependence on the multi-channel audio signal.

First claim

The invention claimed is:

1. A multi-channel audio decoder for providing at least two output audio signals on the basis of an encoded representation, comprising:
a weighting combiner configured to perform a weighted combination of a downmix signal, a decorrelated signal and a residual signal, to acquire one of the at least two output audio signals, wherein the downmix signal, the decorrelated signal and the residual signal are derived from the encoded representation; and
a weight determinator configured to determine a weight describing a contribution of the decorrelated signal in the weighted combination in dependence on the residual signal;
wherein the weight determinator is configured to determine the weight describing the contribution of the decorrelated signal in the weighted combination in dependence on the decorrelated signal,
wherein the weighting combiner and the weight determinator are implemented using a hardware apparatus, or a computer, or a combination of a hardware apparatus and a computer.

2. The multi-channel audio decoder according to claim 1 , wherein the weight determinator is configured to acquire upmix parameters on the basis of the encoded representation, and to determine the weight describing the contribution of the decorrelated signal in the weighted combination in dependence on the upmix parameters.

3. The multi-channel audio decoder according to claim 1 , wherein the weight determinator is configured to determine the weight describing in the contribution of the decorrelated signal in the weighted combination such that the weight of the decorrelated signal decreases with increasing energy of the residual signal.

4. The multi-channel audio decoder according to claim 1 , wherein the weight determinator is configured to determine the weight describing the contribution of the decorrelated signal in the weighted combination such that a maximum weight, which is determined by a decorrelated signal upmix parameter, is associated to the decorrelated signal if an energy of the residual signal is zero, and such that a zero weight is associated to the decorrelated signal if an energy of the residual signal weighted with a residual signal weighting coefficient is larger than or equal to an energy of the decorrelated signal, weighted with the decorrelated signal upmix parameter.

5. The multi-channel audio decoder according to claim 1 , wherein the weight determinator is configured to compute a weighted energy value of the decorrelated signal, weighted in dependence on one or more decorrelated signal upmix parameters, and to compute a weighted energy value of the residual signal, weighted using one or more residual signal upmix parameters, to determine a factor in dependence on the weighted energy value of the decorrelated signal and the weighted energy value of the residual signal, and to acquire the weight describing the contribution of the decorrelated signal to one of the at least two output audio signals on the basis of the factor or to use the factor as the weight describing the contribution of the decorrelated signal to one of the at least two output audio signals.

6. The multi-channel audio decoder according to claim 5 , wherein the weight determinator is configured to multiply the factor with a decorrelated signal upmix parameter, to acquire the weight describing the contribution of the decorrelated signal to one of the at least two output audio signals.

7. The multi-channel audio decoder according to claim 5 , wherein the weight determinator is configured to compute an energy of the decorrelated signal, weighted using decorrelated signal upmix parameters, over a plurality of upmix channels and time slots, to acquire the weighted energy value of the decorrelated signal.

8. The multi-channel audio decoder according to claim 5 , wherein the weight determinator is configured to compute the energy of the residual signal, weighted using residual signal upmix parameters, over a plurality of upmix channels and time slots, to acquire the weighted energy value of the residual signal.

9. The multi-channel audio decoder according to claim 5 , wherein the weight determinator is configured to compute the factor in dependence on a difference between the weighted energy value of the decorrelated signal and the weighted energy value of the residual signal.

10. The multi-channel audio decoder according to claim 9 , wherein the weight determinator is configured to compute the factor in dependence on a ratio between
a difference between the weighted energy value of the decorrelated signal and the weighted energy value of the residual signal, and
the weighted energy value of the decorrelated signal.

11. The multi-channel audio decoder according to claim 5 , wherein the weight determinator is configured to determine weights describing contributions of the decorrelated signal to two or more of the at least two output audio signals,
wherein the weight determinator is configured to determine a contribution of the decorrelated signal to a first output audio signal on the basis of the weighted energy value of the decorrelated signal and a first-channel decorrelated signal upmix parameter, and
wherein the weight determinator is configured to determine a contribution of the decorrelated signal to a second output audio channel on the basis of the weighted energy value of the decorrelated signal and a second-channel decorrelated signal upmix parameter.

12. The multi-channel audio decoder according to claim 1 , wherein the weighted combiner is configured to disable a contribution of the decorrelated signal to the weighted combination if a residual energy exceeds a decorrelator energy.

13. The multi-channel audio decoder according to claim 1 , wherein the weighting combiner is configured to compute two output audio signals ch 1 , ch 2 of the at least two output audio signals according to

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Assignees

• Fraunhofer Ges Forschung

Inventors

• Dick Sascha
• Helmrich Christian
• Hilpert Johannes
• Hoelzer Andreas

Classifications

• G10L19/008 Primary

  Multichannel audio signal coding or decoding using interchannel correlation to reduce redundancy, e.g. joint-stereo, intensity-coding or matrixing · CPC title

• G10L19/20

  using sound class specific coding, hybrid encoders or object based coding · CPC title

• H04S2400/03

  Aspects of down-mixing multi-channel audio to configurations with lower numbers of playback channels, e.g. 7.1 -> 5.1 (H04S2400/01 takes precedence) · CPC title

• H04S1/007

  in which the audio signals are in digital form (data reduction aspects thereof based on psychoacoustics G10L19/02) · CPC title

• G10L19/0017

  Lossless audio signal coding; Perfect reconstruction of coded audio signal by transmission of coding error (G10L19/24 takes precedence) · CPC title