Patent ID: 8144879

Claim:
A method of processing a stereo signal obtained from an encoder, which encodes an N-channel audio signal into spatial parameters and a stereo down-mix signal comprising first and second stereo signals, the method comprising the steps of: adding a first signal and a third signal to obtain a first output signal, wherein said first signal comprises said first stereo signal modified by a first complex function, and wherein said third signal comprises said second stereo signal modified by a third complex function; and adding a second signal and a fourth signal to obtain a second output signal, wherein said fourth signal comprises said second stereo signal modified by a fourth complex function and wherein said second signal comprises said first stereo signal modified by a second complex function; wherein said first function comprises first and second function parts wherein the output of said second function part increases when said spatial parameters indicate that a contribution of the rear channels in said first stereo signal increases as compared to the contribution of the front channels in said first stereo signal, and said second function part comprises a phase shift which is substantially equal to plus or minus 90 degrees.