Multichannel Audio Coding

Disciosed is a method for decoding M encoded audio channels represenfing N audio channels, where N is two or more, and a set of one or more spatial parameters, wherein one or more of said spatial parameters are differentially encoded. The method comprises: a) receiving said M encoded audio channels and said set of spatial pararneters, b) applying a differential decoding procoss to the one or more differentially,encoded spatial parameters, c) deriving N audio signals from said M encoded channels, wherein each audio signal is divided into a plurality of frequency bands, wherein each band comprises one ro more spectral components, and d) generating a multichannel output signals from the N audio signais and the spatial parameters. M is two or more, at least one of said N audio signals is a correlated signal derived from a weighted combination of at least two of said M encoded audio channels. Said set of spatial parameters inciudes a first parameter indicative of the amounl of an utcorrelatedsignai to mix with a correiated sigrral. Step d) inciudes deriving at least one uncorrelated signal from said at least one correlated signal, and controliing the proportion of said at least one correlated signal to said at least one uncorrelated signal in at least one charnel of said multichannel output signal in response to one or ones of said spatial parameters, wherein said controlling is at leasf partly in accordance with said first parameter.

Disciosed is a method for decoding M encoded audio channels represenfing N audio channels, where N is two or more, and a set of one or more spatial parameters, wherein one or more of said spatial parameters are differentially encoded. The method comprises: a) receiving said M encoded audio channels and said set of spatial pararneters, b) applying a differential decoding procoss to the one or more differentially,encoded spatial parameters, c) deriving N audio signals from said M encoded channels, wherein each audio signal is divided into a plurality of frequency bands, wherein each band comprises one ro more spectral components, and d) generating a multichannel output signals from the N audio signais and the spatial parameters. M is two or more, at least one of said N audio signals is a correlated signal derived from a weighted combination of at least two of said M encoded audio channels. Said set of spatial parameters inciudes a first parameter indicative of the amounl of an utcorrelatedsignai to mix with a correiated sigrral. Step d) inciudes deriving at least one uncorrelated signal from said at least one correlated signal, and controliing the proportion of said at least one correlated signal to said at least one uncorrelated signal in at least one charnel of said multichannel output signal in response to one or ones of said spatial parameters, wherein said controlling is at leasf partly in accordance with said first parameter.