Patent ID: 7805313

Claim:
A machine-implemented method for encoding a multi-channel audio signal having a plurality of audio input channels comprising a plurality of regular channels and at least one low-frequency channel, the machine-implemented method comprising: the machine applying a parametric audio encoding technique to generate parametric audio codes for all of the audio input channels for a first frequency region corresponding to one or more sub-bands below a specified cut-off frequency; and the machine applying the parametric audio encoding technique to generate parametric audio codes for only the regular channels for a second frequency region corresponding to one or more sub-bands above the specified cut-off frequency, wherein: the parametric audio encoding technique generates the parametric audio codes based on inter-channel differences; for the first frequency region, the parametric audio encoding technique generates inter-channel difference information corresponding to all of the audio input channels; and for the second frequency region, the parametric audio encoding technique generates inter-channel difference information corresponding to only the regular channels and not with respect to the at least one low-frequency channel.