Patent ID: 9224400
Filing Date: 2015-12-29
Classification: G10L,H04S

Abstract:
1. A method of downmixing a plurality of input audio signals containing input data into at least two output audio signals corresponding to spatially related channels, wherein maximal downmix coefficients are predefined, at least one in-range condition on each of the at least two output audio signals is predefined and the input audio signals are partitioned into predefined subgroups, wherein at least one of the subgroups comprises two or more input audio signals, the in-range condition on each of the at least two output audio signals being an upper bound on the output audio signal or a lower bound on the output audio signal or a requirement for the output audio signal to remain in an interval having a lower and an upper bound, the method comprising: determining a limiting factor for each subgroup; determining downmix coefficients for each subgroup as products of the maximal downmix coefficients for the subgroup and the limiting factor for the subgroup; applying the downmix coefficients to downmix the plurality of input audio signals into the at least two output audio signals corresponding to spatially related channels, wherein determining the limiting factor for a subgroup includes the substeps of: determining, for each of the output audio signals to which the input audio signals in the subgroup contribute, a preliminary limiting factor for the subgroup, in order to satisfy, in view of the input data, the in-range condition on the output audio signal; and determining, as the limiting factor for the subgroup, the minimum of the preliminary limiting factors for the subgroup, in order to jointly satisfy, in view of the input data, the in-range condition on each of the output audio signals.