Patent ID: 8270618

Claim:
Apparatus for processing a multi-channel audio signal, the multi-channel audio signal having at least three original channels, comprising: a provider for providing a first downmix channel and a second downmix channel, the first and the second downmix channels being derived from the original channels; a calculator for calculating channel side information for a selected original channel of the original signals, the calculator being operative to calculate the channel side information such that a downmix channel or a combined downmix channel comprising the first and the second downmix channel, when weighted using the channel side information, results in an approximation of the selected original channel; a generator for generating output data, the output data comprising the channel side information; wherein at least one of the provider, the calculator or the generator comprises a hardware implementation; wherein the multi-channel audio signal includes a left channel, a left surround channel, a right channel and a right surround channel, wherein the provider is operative to provide the first downmix channel as a left downmix channel and to provide the second downmix channel as a right downmix channel, the left and the right downmix channels being formed such that a result, when played, is a stereo representation of the multi-channel audio signal, and wherein the calculator is operative: to calculate the channel side information for the left channel as the selected original channel using the left downmix channel, to calculate the channel side information for the right channel as the selected original channel using the right downmix channel, to calculate the channel side information for the left surround channel as the selected original channel using the left downmix channel, and to calculate the channel side information for the right surround channel as the selected original channel using the right downmix channel.