Decoder and method for a generalized spatial-audio-object-coding parametric concept for multichannel downmix/upmix cases by comparing a downmix channel matrix eigenvalues to a threshold

A decoder for generating an audio output signal comprising one or more audio output channels from a downmix signal comprising one or more downmix channels, wherein the downmix signal encodes two or more audio object signals, wherein the decoder comprises:

• a threshold determiner for determining a threshold value depending on a signal energy or a noise energy of at least one of the two or more audio object signals or depending on a signal energy or a noise energy of at least one of the one or more downmix channels, and
• a processing unit for generating the one or more audio output channels from the one or more downmix channels depending on the threshold value,
• wherein the processing unit is configured to generate the one or more audio output channels from the one or more downmix channels depending on an object covariance matrix of the one or more audio object signals, depending on a downmix matrix for downmixing the two or more audio object signals to obtain the one or more downmix channels, and depending on the threshold value,
• wherein the processing unit is configured to generate the one or more audio output channels from the one or more downmix channels by applying the threshold value in a function to inverse a downmix channel cross correlation matrix Q,
• wherein Q is defined as Q=DED*,
• wherein D is the downmix matrix for downmixing the two or more audio object signals to obtain the two or more downmix channels,
• wherein E is the object covariance matrix of the one or more audio object signals, and
• wherein the processing unit is configured to generate the one or more audio output channels from the one or more downmix channels by computing eigenvalues of the downmix channel cross correlation matrix Q;
• wherein each eigenvalue except largest eigenvalue is compared to the threshold value, and omitted if they are smaller.