Multi-channel decorrelator, multi-channel audio decoder, multi-channel audio encoder, methods and computer program using a premix of decorrelator input signals

A method for providing a plurality of decorrelated audio signals on the basis of a plurality of decorrelator input audio signals, the method comprising:

• premixing a first set {circumflex over (Z)} of N decorrelator input audio signals into a second set {circumflex over (Z)}mix of K decorrelator input audio signals, wherein K<N;
• decorrelating the second set {circumflex over (Z)}mix of K decorrelator input audio signals, to provide a first set {circumflex over (Z)}mixdec of K′ decorrelator output audio signals on the basis of the second set {circumflex over (Z)}mix of K decorrelator input audio signals;
• and
• upmixing the first set {circumflex over (Z)}mixdec of K′ decorrelator output audio signals into a second set of N′ decorrelator output audio signals, wherein N′>K′;
• wherein the first set {circumflex over (Z)} of N decorrelator input audio signals is premixed into the second set {circumflex over (Z)}mix of K decorrelator input audio signals using a premixing matrix Mpre according to
• {circumflex over (Z)}mix=Mpre{circumflex over (Z)}
• wherein the first set {circumflex over (Z)}mixdec of K′ decorrelator output audio signals is acquired on the basis of the second set {circumflex over (Z)}mix of K decorrelator input audio signals, and
• wherein the first set {circumflex over (Z)}mixdec of K′ decorrelator output audio signals is upmixed into the second set W of N′ decorrelator output audio signals using a postmixing matrix Mpost according to
• W=Mpost{circumflex over (Z)}mixdec;
• wherein the premixing matrix Mpre is selected in dependence on correlation characteristics or covariance characteristics of signals of the first set {circumflex over (Z)} of N decorrelator input audio signals.

A multi-channel decorrelator for providing a plurality of decorrelated audio signals on the basis of a plurality of decorrelator input audio signals, comprising:

• a premixer configured to premix a first set {circumflex over (Z)} of N decorrelator input audio signals into a second set {circumflex over (Z)}mix of K decorrelator input audio signals, wherein K<N;
• a decorrelator core configured to decorrelate the second set {circumflex over (Z)}mix of K decorrelator input audio signals, to provide a first set {circumflex over (Z)}mixdec of K′ decorrelator output audio signals on the basis of the second set {circumflex over (Z)}mix of K decorrelator input audio signals;
• and
• wherein the multi-channel decorrelator comprises an upmixer configured to upmix the first set {circumflex over (Z)}mixdec of K′ decorrelator output audio signals into a second set W of N′ decorrelator output audio signals, wherein N′>K′;
• wherein the premixer is configured to premix the first set {circumflex over (Z)} of N decorrelator input audio signals into the second set {circumflex over (Z)}mix of K decorrelator input audio signals using a premixing matrix Mpre according to
• {circumflex over (Z)}mix=Mpre{circumflex over (Z)}
• wherein the decorrelator core is configured to acquire the first set {circumflex over (Z)}mixdec of K′ decorrelator output audio signals on the basis of the second set {circumflex over (Z)}mix of K decorrelator input audio signals, and
• wherein the upmixer is configured to upmix the first set {circumflex over (Z)}mixdec of K′ decorrelator output audio signals into the second set W of N′ decorrelator output audio signals using a postmixing matrix Mpost according to
• W=Mpost{circumflex over (Z)}mixdec;
• wherein the multi-channel decorrelator further comprises a matrix selector configured to select the premixing matrix Mpre in dependence on correlation characteristics or covariance characteristics of channel signals of the first set {circumflex over (Z)} of N decorrelator input audio signals,
• wherein the multi-channel decorrelator is configured to acquire the postmixing matrix Mpost according to
• Mpost=MpreH(MpreMpreH)−1;
• wherein the multi-channel decorrelator is implemented using a hardware apparatus, or using a computer, or using a combination of a hardware apparatus and a computer.

A method for providing a plurality of decorrelated audio signals on the basis of a plurality of decorrelator input audio signals, the method comprising:

• premixing a first set {circumflex over (Z)} of N decorrelator input audio signals into a second set {circumflex over (Z)}mix of K decorrelator input audio signals, wherein K<N;
• decorrelating the second set {circumflex over (Z)}mix of K decorrelator input audio signals, to provide a first set {circumflex over (Z)}mixdec of K′ decorrelator output audio signals on the basis of the second set {circumflex over (Z)}mix of K decorrelator input audio signals;
• and
• upmixing the first set {circumflex over (Z)}mix of of K′ decorrelator output audio signals into a second set W of N′ decorrelator output audio signals, wherein N′>K′;
• wherein the first set {circumflex over (Z)} of N decorrelator input audio signals is premixed into the second set {circumflex over (Z)}mix of K decorrelator input audio signals using a premixing matrix Mpre according to
• {circumflex over (Z)}mix=Mpre{circumflex over (Z)}
• wherein the first set {circumflex over (Z)}mixdec of K′ decorrelator output audio signals is acquired on the basis of the second set {circumflex over (Z)}mix of K decorrelator input audio signals, and
• wherein the first set {circumflex over (Z)}mixdec of K′ decorrelator output audio signals is upmixed into the second set W of N′ decorrelator output audio signals using a postmixing matrix Mpostaccording to
• W=Mpost{circumflex over (Z)}mixdec;
• wherein the premixing matrix Mpre is selected in dependence on correlation characteristics or covariance characteristics of channel signals of the first set {circumflex over (Z)} of N decorrelator input audio signals;
• wherein the method comprises acquiring the postmixing matrix Mpost according to
• Mpost=MpreH(MpreMpreH)−1.

A multi-channel decorrelator for providing a plurality of decorrelated audio signals on the basis of a plurality of decorrelator input audio signals, comprising:

• a premixer configured to premix a first set {circumflex over (Z)} of N decorrelator input audio signals into a second set {circumflex over (Z)}mix of K decorrelator input audio signals, wherein K<N;
• a decorrelator core configured to decorrelate the second set {circumflex over (Z)}mix of K decorrelator input audio signals to provide a first set {circumflex over (Z)}mixdec of K′ decorrelator output audio signals;
• and
• an upmixer configured to upmix the first set {circumflex over (Z)}mixdec of K′ decorrelator output audio signals into a second set W of N′ decorrelator output audio signals, wherein N′>K′;
• wherein the premixer is configured to premix the first set {circumflex over (Z)} of N decorrelator input audio signals into the second set {circumflex over (Z)}mix of K decorrelator input audio signals using a premixing matrix Mpre according to
• {circumflex over (Z)}mix=Mpre{circumflex over (Z)}
• wherein the decorrelator core is configured to acquire the first set {circumflex over (Z)}mixdec of K′ decorrelator output audio signals on the basis of the second set {circumflex over (Z)}mix of K decorrelator input audio signals, wherein a decorrelator functionality is performed on the K decorrelator input audio signals of the second set {circumflex over (Z)}mix of K decorrelator input audio signals, and
• wherein the upmixer is configured to upmix the first set {circumflex over (Z)}mixdec of K′ decorrelator output audio signals into the second set W of N′ decorrelator output audio signals using a postmixing matrix Mpost according to
• W=Mpost{circumflex over (Z)}mixdec
• wherein the multi-channel decorrelator comprises a matrix selector configured to select the premixing matrix Mpre in dependence on correlation characteristics or covariance characteristics of signals of the first set {circumflex over (Z)} of N decorrelator input audio signals,
• such that decorrelator input signals of the first set {circumflex over (Z)} of N decorrelator input signals, which are closely related, are combined into a single decorrelator input signal of the second set {circumflex over (Z)}mix of K decorrelator input signals, and are consequently processed by a common individual decorrelator;
• wherein the multi-channel decorrelator is implemented using a hardware apparatus, or using a computer, or using a combination of a hardware apparatus and a computer.

A multi-channel decorrelator for providing a plurality of decorrelated audio signals on the basis of a plurality of decorrelator input audio signals, comprising:

• a premixer configured to premix a first set {circumflex over (Z)} of N decorrelator input audio signals into a second set {circumflex over (Z)}mix of K decorrelator input audio signals, wherein K<N;
• a decorrelator core configured to decorrelate the second set {circumflex over (Z)}mix of K decorrelator input audio signals to provide a first set {circumflex over (Z)}mixdec of K′ decorrelator output audio signals;
• and
• an upmixer configured to upmix the first set {circumflex over (Z)}mixdec of K′ decorrelator output audio signals into a second set W of N′ decorrelator output audio signals, wherein N′>K′;
• wherein the premixer is configured to premix the first set {circumflex over (Z)} of N decorrelator input audio signals into the second set {circumflex over (Z)}mix l of K decorrelator input audio signals using a premixing matrix Mpre according to
• {circumflex over (Z)}mix=Mpre{circumflex over (Z)}
• wherein the decorrelator core is configured to acquire the first set {circumflex over (Z)}mixdec of K′ decorrelator output audio signals on the basis of the second set {circumflex over (Z)}mix of K decorrelator input audio signals, wherein a decorrelator functionality is performed on the K decorrelator input audio signals of the second set {circumflex over (Z)}mix of K decorrelator input audio signals, and
• wherein the upmixer is configured to upmix the first set {circumflex over (Z)}mixdec of K′ decorrelator output audio signals into the second set W of N′ decorrelator output audio signals using a postmixing matrix Mpost according to
• W=Mpost{circumflex over (Z)}mixdec;
• wherein the multi-channel decorrelator comprises a matrix selector configured to select the premixing matrix Mpre in dependence on correlation characteristics or covariance characteristics between signals of the first set {circumflex over (Z)} of N decorrelator input audio signals;
• wherein the multi-channel decorrelator is implemented using a hardware apparatus, or using a computer, or using a combination of a hardware apparatus and a computer.

A multi-channel decorrelator for providing a plurality of decorrelated audio signals on the basis of a plurality of decorrelator input audio signals, comprising:

• a premixer configured to premix a first set {circumflex over (Z)} of N decorrelator input audio signals into a second set {circumflex over (Z)}mix of K decorrelator input audio signals, wherein K<N;
• a decorrelator core configured to decorrelate the second set {circumflex over (Z)}mix of K decorrelator input audio signals to provide a first set {circumflex over (Z)}mixdec of K′ decorrelator output audio signals;
• and
• an upmixer configured to upmix the first set {circumflex over (Z)}mixdec of K′ decorrelator output audio signals into a second set W of N′ decorrelator output audio signals, wherein N′>K′;
• wherein the premixer is configured to premix the first set {circumflex over (Z)} of N decorrelator input audio signals into the second set {circumflex over (Z)}mix of K decorrelator input audio signals using a premixing matrix Mpre according to
• {circumflex over (Z)}mix=Mpre{circumflex over (Z)}
• wherein the decorrelator core is configured to acquire the first set {circumflex over (Z)}mixdec of K′ decorrelator output audio signals on the basis of the second set {circumflex over (Z)}mix of K decorrelator input audio signals, wherein a decorrelator functionality is performed on the K decorrelator input audio signals of the second set {circumflex over (Z)}mix of K decorrelator input audio signals, and
• wherein the upmixer is configured to upmix the first set {circumflex over (Z)}mixdec of K′ decorrelator output audio signals into the second set W of N′ decorrelator output audio signals using a postmixing matrix Mpost according to
• W=Mpost{circumflex over (Z)}mixdec;
• wherein the multi-channel decorrelator comprises a matrix selector configured to select the premixing matrix Mpre in dependence on correlation characteristics or covariance characteristics of signals of the first set {circumflex over (Z)} of N decorrelator input audio signals,
• such that decorrelator input signals of the first set {circumflex over (Z)} of N decorrelator input signals, which are closely related, are combined into a single decorrelator input signal of the second set {circumflex over (Z)}mix of K decorrelator input signals, and are consequently processed by a common individual decorrelator, and
• such that it is avoided that substantially different decorrelator input audio signals of the first set of decorrelator input signals are premixed into a single decorrelator input audio signal;
• wherein the multi-channel decorrelator is implemented using a hardware apparatus, or using a computer, or using a combination of a hardware apparatus and a computer.

A multi-channel decorrelator for providing a plurality of decorrelated audio signals on the basis of a plurality of decorrelator input audio signals, comprising:

• a premixer configured to premix a first set {circumflex over (Z)} of N decorrelator input audio signals into a second set {circumflex over (Z)}mix of K decorrelator input audio signals, wherein K<N;
• a decorrelator core configured to decorrelate the second set {circumflex over (Z)}mix of K decorrelator input audio signals to provide a first set {circumflex over (Z)}mixdec of K′ decorrelator output audio signals;
• and
• an upmixer configured to upmix the first set {circumflex over (Z)}mixdec of K′ decorrelator output audio signals into a second set W of N′ decorrelator output audio signals, wherein N′>K′;
• wherein the premixer is configured to premix the first set {circumflex over (Z)} of N decorrelator input audio signals, which comprises a plurality of channel signals, into the second set {circumflex over (Z)}mix of K decorrelator input audio signals using a premixing matrix Mpre according to
• {circumflex over (Z)}mix=Mpre{circumflex over (Z)}
• wherein the decorrelator core is configured to acquire the first set {circumflex over (Z)}mixdec of K′ decorrelator output audio signals on the basis of the second set {circumflex over (Z)}mix of K decorrelator input audio signals, wherein a decorrelator functionality is performed on the K decorrelator input audio signals of the second set {circumflex over (Z)}mix of K decorrelator input audio signals, and
• wherein the upmixer is configured to upmix the first set {circumflex over (Z)}mixdec of K′ decorrelator output audio signals into the second set W of N′ decorrelator output audio signals using a postmixing matrix Mpost according to
• W=Mpost{circumflex over (Z)}mixdec;
• wherein the multi-channel decorrelator comprises a matrix selector configured to select the premixing matrix Mpre in dependence on correlation characteristics or covariance characteristics between the channel signals of the first set {circumflex over (Z)} of N decorrelator input audio signals;
• wherein the multi-channel decorrelator is implemented using a hardware apparatus, or
• using a computer, or using a combination of a hardware apparatus and a computer.