MASA direction field alignment

MASA does not have a fixed assignment between physical sound source directions and the spatial metadata field assignment, e.g., the IVAS encoder may assign the direction with the higher energy to the first field. This may shuffle the metadata of a direction into both direction fields. Any further operation of reducing the TF-resolution would now aggregate over parameter tiles originating from different original directions, resulting into smearing of the parameters and perceptual quality degradation.

A solution with a pre-processing step aligning the direction fields will be provided.