Patent ID: 8370134

Claim:
A method for coding by principal component analysis (PCA) of a multi-channel audio signal (C 1 , . . . ,C M ), comprising the steps of: decomposing at least two channels (L, R) of said audio signal into a plurality of frequency sub-bands (I(b 1 ), . . . I(b N ), r(b 1 ), . . . r(b N )): calculating a rotation angle (θ(b 1 ), . . . θ(b N )) per sub-band among at least some of said plurality of frequency sub-bands, as at least one transformation parameter; transforming at least some of said plurality of frequency sub-bands into a plurality of frequency sub-components using at least one of the calculated rotation angles (θ(b 1 ), . . . θ(b N )), as the at least one transformation parameter, said plurality of frequency sub-components comprising principal frequency sub-components (CP(b 1 ), . . . CP(b N )); combining at least some of said principal frequency sub-components (CP(b 1 ), . . . CP(b N )) in order to form a principal component (CP); and forming a coded audio signal (SC) representing said multi-channel audio signal (C 1 , . . . C M ), said coded audio signal (SC) comprising said principal component (CP) and said at least one transformation parameter (θ(b 1 ), . . . θ(b N )).