Apparatus for providing an upmix signal representation on the basis of the downmix signal representation, apparatus for providing a bitstream representing a multi-channel audio signal, methods, computer programs and bitstream representing a multi-channel audio signal using a linear combination parameter

An apparatus for providing a bitstream representing a multi-channel audio signal, the apparatus comprising:

• a downmixer configured to provide a downmix signal on the basis of a plurality of audio object signals;
• a side information provider configured to provide an object-related parametric side information describing characteristics of the audio object signals and downmix parameters, and a linear combination parameter describing desired contributions of a user-specified rendering matrix and of a target rendering matrix to a modified rendering matrix to be used by an apparatus for providing an upmix signal representation on the basis of the bitstream;
• and
• a bitstream formatter configured to provide a bitstream comprising a representation of the downmix signal, of the object-related parametric side information and of the linear combination parameter;
• wherein the user-specified rendering matrix defines a desired contribution of a plurality of audio objects to one, two or more output audio channels.

An audio processing method for providing an upmix signal representation on the basis of a downmix signal representation and an object-related parametric information, which are comprised in a bitstream representation of an audio content, and in a dependence on a user-specified rendering matrix which defines a desired contribution of a plurality of audio objects to one, two or more output audio channels, the method comprising:

• evaluating a bitstream element representing a linear combination parameter, in order to acquire the linear combination parameter;
• acquiring a modified rendering matrix using a linear combination of a user-specified rendering matrix and a distortion-free target rendering matrix in dependence on the linear combination parameter;
• and
• acquiring the upmix signal representation on the basis of the downmix signal representation and the object-related parametric information using the modified rendering matrix.

A method for providing a bitstream representing a multi-channel audio signal, the method comprising:

• providing a downmix signal on the basis of a plurality of audio object signals;
• providing an object-related parametric side information describing characteristics of the audio object signals and downmix parameters, and a linear combination parameter describing desired contributions of a user-specified rendering matrix and of a target rendering matrix to a modified rendering matrix;
• and
• providing a bitstream comprising a representation of the downmix signal, of the object-related parametric side information and the linear combination parameter;
• wherein the user-specified rendering matrix defines a desired contribution of a plurality of audio objects to one, two or more output audio channels.

A non-transitory computer readable medium including a computer program for performing, when the computer program runs on a computer, an audio processing method for providing an upmix signal representation on the basis of a downmix signal representation and an object-related parametric information, which are comprised in a bitstream representation of an audio content, and in a dependence on a user-specified rendering matrix which defines a desired contribution of a plurality of audio objects to one, two or more output audio channels, the method comprising:

• evaluating a bitstream element representing a linear combination parameter, in order to acquire the linear combination parameter;
• acquiring a modified rendering matrix using a linear combination of a user-specified rendering matrix and a distortion-free target rendering matrix in dependence on the linear combination parameter;
• and
• acquiring the upmix signal representation on the basis of the downmix signal representation and the object-related parametric information using the modified rendering matrix.

A non-transitory computer readable medium including a computer program for performing, when the computer program runs on a computer, a method for providing a bitstream representing a multi-channel audio signal, the method comprising:

• providing a downmix signal on the basis of a plurality of audio object signals;
• providing an object-related parametric side information describing characteristics of the audio object signals and downmix parameters, and a linear combination parameter describing desired contributions of a user-specified rendering matrix and of a target rendering matrix to a modified rendering matrix;
• and
• providing a bitstream comprising a representation of the downmix signal, of the object-related parametric side information and the linear combination parameter;
• wherein the user-specified rendering matrix defines a desired contribution of a plurality of audio objects to one, two or more output audio channels.