Audio or video encoder, audio or video decoder and related methods for processing multi-channel audio or video signals using a variable prediction direction

An audio or video encoder for encoding a multi-channel audio or video signal comprising two or more channel signals, comprising:

• an encoder calculator for calculating a first combination signal and a prediction residual signal using a first channel signal and a second channel signal and prediction information and a prediction direction indicator indicating a prediction direction associated with the prediction residual signal, so that a prediction residual signal, when combined with a prediction signal derived from the first combination signal or a signal derived from the first combination signal and the prediction information results in a second combination signal,
• wherein the encoder calculator comprises a combiner for combining the first channel signal and the second channel signal in two different ways to acquire the first combination signal and the second combination signal;
• an optimizer for calculating the prediction information so that the prediction residual signal fulfills an optimization target;
• a prediction direction calculator for calculating the prediction direction indicator indicating the prediction direction associated with the prediction residual signal;
• a signal encoder for encoding the first combination signal and the prediction residual signal to acquire an encoded first combination signal and an encoded prediction residual signal;
• and
• an output interface for combining the encoded first combination signal, the encoded prediction residual signal and the prediction information to acquire an encoded multi-channel audio or video signal.

A method of decoding an encoded multi-channel audio or video signal, the encoded multi-channel audio or video signal comprising an encoded first combination signal, an encoded prediction residual signal and prediction information, comprising:

• decoding the encoded first combination signal to acquire a decoded first combination signal, and decoding the encoded residual signal to acquire a decoded residual signal;
• and
• calculating a decoded multi-channel signal comprising a decoded first channel signal, and a decoded second channel signal using the decoded residual signal, the prediction information, the decoded first combination signal and a prediction direction indicator indicating a prediction direction associated with the decoded prediction residual signal, so that the decoded first channel signal and the decoded second channel signal are at least approximations of a first channel signal and a second channel signal of a multi-channel signal,
• wherein calculating the decoded multi-channel signal comprises using a first calculation rule for calculating the decoded multi-channel signal in case of a first state of the prediction direction indicator and using a second different calculation rule for calculating the decoded multi-channel signal in case of a second different state of the prediction direction indicator.

A method of encoding a multi-channel audio or video signal comprising two or more channel signals, comprising:

• calculating a first combination signal and a prediction residual signal using a first channel signal and a second channel signal, prediction information and a prediction direction indicator indicating a prediction direction associated with the prediction residual signal, so that a prediction residual signal, when combined with a prediction signal derived from the first combination signal or a signal derived from the first combination signal and the prediction information results in a second combination signal,
• combining the first channel signal and the second channel signal in two different ways to acquire the first combination signal and the second combination signal;
• calculating the prediction information so that the prediction residual signal fulfills an optimization target;
• calculating the prediction direction indicator indicating the prediction direction associated with the prediction residual signal;
• encoding the first combination signal and the prediction residual signal to acquire an encoded first combination signal and an encoded residual signal;
• and
• combining the encoded first combination signal, the encoded prediction residual signal and the prediction information to acquire an encoded multi-channel audio or video signal.

A non-transitory storage medium having stored thereon a computer program for performing, when running on a computer or a processor, the method of decoding an encoded multi-channel audio or video signal, the encoded multi-channel audio or video signal comprising an encoded first combination signal, an encoded prediction residual signal and prediction information, said method comprising:

• decoding the encoded first combination signal to acquire a decoded first combination signal, and decoding the encoded residual signal to acquire a decoded residual signal;
• and
• calculating a decoded multi-channel signal comprising a decoded first channel signal, and a decoded second channel signal using the decoded residual signal, the prediction information, the decoded first combination signal and a prediction direction indicator indicating a prediction direction associated with the decoded prediction residual signal, so that the decoded first channel signal and the decoded second channel signal are at least approximations of the first channel signal and the second channel signal of the multi-channel signal,
• wherein calculating the decoded multi-channel signal comprises using a first calculation rule for calculating the decoded multi-channel signal in case of a first state of the prediction direction indicator and using a second different calculation rule for calculating the decoded multi-channel signal in case of a second different state of the prediction direction indicator.

A non-transitory storage medium having stored thereon a computer program for performing, when running on a computer or a processor, the method of encoding a multi-channel audio or video signal comprising two or more channel signals, said method comprising:

• calculating a first combination signal and a prediction residual signal using a first channel signal and a second channel signal prediction information and a prediction direction indicator indicating a prediction direction associated with the decoded prediction residual signal, so that a prediction residual signal, when combined with a prediction signal derived from the first combination signal or a signal derived from the first combination signal and the prediction information results in a second combination signal,
• combining the first channel signal and the second channel signal in two different ways to acquire the first combination signal and the second combination signal;
• calculating the prediction information so that the prediction residual signal fulfills an optimization target;
• calculating the prediction direction indicator indicating the prediction direction associated with the prediction residual signal;
• encoding the first combination signal and the prediction residual signal to acquire an encoded first combination signal and an encoded residual signal;
• and
• combining the encoded first combination signal, the encoded prediction residual signal and the prediction information to acquire an encoded multi-channel audio or video signal.

An audio or video decoder for decoding an encoded multi-channel audio or video signal, the encoded multi-channel audio or video signal comprising an encoded first combination signal, an encoded prediction residual signal and prediction information, comprising:

• a signal decoder for decoding the encoded first combination signal to acquire a decoded first combination signal, and for decoding the encoded residual signal to acquire a decoded residual signal;
• and
• a decoder calculator for calculating a decoded multi-channel signal comprising a decoded first channel signal, and a decoded second channel signal using the decoded residual signal, the prediction information, the decoded first combination signal and a prediction direction indicator indicating a prediction direction associated with the decoded prediction residual signal, so that the decoded first channel signal and the decoded second channel signal are at least approximations of a first channel signal and a second channel signal of a multi-channel signal,
• wherein the decoder calculator is configured for using a first calculation rule for calculating the decoded multi-channel signal in case of a first state of the prediction direction indicator and for using a second different calculation rule for calculating the decoded multi-channel signal in case of a second different state of the prediction direction indicator,
• wherein the decoder calculator comprises:
• a predictor for applying the prediction information to the decoded first combination signal or to a signal derived from the decoded first combination signal to acquire a prediction signal;
• a combination signal calculator for calculating a second combination signal by combining the decoded residual signal and the prediction signal;
• and
• a combiner for combining the decoded first combination signal and the second combination signal to acquire a decoded multi-channel audio or video signal comprising the decoded first channel signal and the decoded second channel signal,
• wherein in case of the first state of the prediction direction indicator, the first combination signal is a sum signal and the second combination signal is a difference signal, or wherein in case of the second state of the prediction direction indicator, the first combination signal is a difference signal and the second combination signal is a sum signal.

A method of decoding an encoded multi-channel audio or video signal, the encoded multi-channel audio or video signal comprising an encoded first combination signal, an encoded prediction residual signal and prediction information, comprising:

• decoding the encoded first combination signal to acquire a decoded first combination signal, and decoding the encoded residual signal to acquire a decoded residual signal;
• and
• calculating a decoded multi-channel signal comprising a decoded first channel signal, and a decoded second channel signal using the decoded residual signal, the prediction information, the decoded first combination signal and a prediction direction indicator indicating a prediction direction associated with the decoded prediction residual signal, so that the decoded first channel signal and the decoded second channel signal are at least approximations of a first channel signal and a second channel signal of a multi-channel signal,
• wherein calculating the decoded multi-channel signal comprises using a first calculation rule for calculating the decoded multi-channel signal in case of a first state of the prediction direction indicator and using a second different calculation rule for calculating the decoded multi-channel signal in case of a second different state of the prediction direction indicator,
• wherein the calculating a decoded multi-channel signal comprises:
• applying the prediction information to the decoded first combination signal or to a signal derived from the decoded first combination signal to acquire a prediction signal;
• calculating a second combination signal by combining the decoded residual signal and the prediction signal;
• and
• combining the decoded first combination signal and the second combination signal to acquire a decoded multi-channel audio or video signal comprising the decoded first channel signal and the decoded second channel signal,
• wherein in case of the first state of the prediction direction indicator, the first combination signal is a sum signal and the second combination signal is a difference signal, or wherein in case of the second state of the prediction direction indicator, the first combination signal is a difference signal and the second combination signal is a sum signal.

A non-transitory storage medium having stored thereon a computer program for performing, when running on a computer or a processor, the method of decoding an encoded multi-channel audio or video signal, the encoded multi-channel audio or video signal comprising an encoded first combination signal, an encoded prediction residual signal and prediction information, said method comprising:

• decoding the encoded first combination signal to acquire a decoded first combination signal, and decoding the encoded residual signal to acquire a decoded residual signal;
• and
• calculating a decoded multi-channel signal comprising a decoded first channel signal, and a decoded second channel signal using the decoded residual signal, the prediction information, the decoded first combination signal and a prediction direction indicator indicating a prediction direction associated with the decoded prediction residual signal, so that the decoded first channel signal and the decoded second channel signal are at least approximations of the first channel signal and the second channel signal of the multi-channel signal,
• wherein calculating the decoded multi-channel signal comprises using a first calculation rule for calculating the decoded multi-channel signal in case of a first state of the prediction direction indicator and using a second different calculation rule for calculating the decoded multi-channel signal in case of a second different state of the prediction direction indicator,
• wherein the calculating a decoded multi-channel signal comprises:
• applying the prediction information to the decoded first combination signal or to a signal derived from the decoded first combination signal to acquire a prediction signal;
• calculating a second combination signal by combining the decoded residual signal and the prediction signal;
• and
• combining the decoded first combination signal and the second combination signal to acquire a decoded multi-channel audio or video signal comprising the decoded first channel signal and the decoded second channel signal,
• wherein in case of the first state of the prediction direction indicator, the first combination signal is a sum signal and the second combination signal is a difference signal, or wherein in case of the second state of the prediction direction indicator, the first combination signal is a difference signal and the second combination signal is a sum signal.