GENERATION OF MULTICHANNEL AUDIO SIGNAL

An audio apparatus comprises a receiver (101) arranged to receive a downmix audio signal for a multichannel audio signal and upmix parametric data for upmixing the downmix audio signal. A first artificial neural network (107) generates a set of feature values for the downmix audio signal from samples of the downmix audio signal. A second artificial neural network (109) has input nodes receiving second samples of the downmix audio signal and nodes receiving feature values from the set of feature values. Based on these inputs, the second artificial neural network (109) generates samples of an auxiliary audio signal for the downmix audio signal. A generator (105) generates the multichannel audio signal from the downmix signal and the auxiliary audio signal in dependence on the upmix parametric data. In many embodiments, the operation may be subband based with separate artificial neural networks being used for different subbands.