Multi-channel hierarchical audio coding with compact side-information

A PARAMETRIC REPRESENTATION OF A MULTI-CHANNEL AUDIO SIGNAL DESCRIBES THE SPATIAL PROPERTIES OF THE AUDIO SIGNAL WELL WITH COMPACT SIDE INFORMATION WHEN A COHERENCE INFORMATION, DESCRIBING THE COHERENCE BETWEEN A FIRST AND A SECOND CHANNEL, IS DERIVED WITHIN A HIERARCHICAL ENCODING PROCESS ONLY FOR CHANNEL PAIRS INCLUDING A FIRST CHANNEL HAVING ONLY INFORMATION OF A LEFT SIDE WITH RESPECT TO A LISTENING POSITION AND INCLUDING A SECOND CHANNEL HAVING ONLY INFORMATION FROM A RIGHT SIDE WITH RESPECT TO A LISTENING POSITION. AS WITHIN THE HIERARCHICAL PROCESS THE MULTIPLE AUDIO CHANNELS OF THE AUDIO SIGNAL ARE DOWNMIXED ITERATIVELY INTO MONOPHONIC CHANNELS, ONE CAN PICK THE RELEVANT PARAMETERS FROM AN ENCODING STEP INVOLVING ONLY CHANNEL PAIRS CARRYING THE INFORMATION NEEDED TO DESCRIBE THE SPATIAL PROPERTIES OF THE MULTI-CHANNEL AUDIO SIGNAL.