Patent ID: 7693721

Claim:
A transmitter-implemented method for encoding N input audio signals, N>1, comprising the steps of: (a) the transmitter converting each of the N input audio signals into a plurality of spectral components in a frequency domain; (b) for each of one or more, but not all, of the spectral components, the transmitter downmixing the spectral components corresponding to the N input audio signals to generate a downmixed spectral component, leaving one or more of the spectral components for each of the N input audio signals unmixed; and (c) the transmitter generating an encoded audio bitstream based on the one or more downmixed spectral components and one or more unmixed spectral components, wherein step (c) comprises the steps of: (1) the transmitter replicating each downmixed spectral component to generate a plurality of replicated downmixed spectral components; (2) the transmitter converting the plurality of replicated downmixed spectral components and the one or more unmixed spectral components into N hybrid audio signals in a time domain; and (3) the transmitter applying an audio coding algorithm to the N hybrid audio signals to generate the encoded audio bitstream.