A method of encoding a multichannel signal, such as a stereophonic audio
signal, including at least first and second signal components includes
transforming at least the first and second signal components by a
predetermined transformation into a principal signal including most of
the signal energy and at least one residual signal including less energy
than the principal signal. The predetermined transformation is
parameterized by at least one transformation parameter. The method
further includes representing the multichannel signal at least by the
principal signal and the transformation parameter.