Space Warping Based Dimensionality Reduction of Higher Order Ambisonics Signals

Abstract

A novel approach to non-uniform spatial resolution encoding and dimensionality reduction of Higher Order Ambisonics spatial audio content is proposed. Space warping is applied to modify the spatial arrangement of the audio scene such that the coefficient energy is packed in few low order coefficients. The underlying idea is to squeeze or stretch parts of the spherical coordinates. In contrast to conventional Mixed Order Ambisonics, our approach is based on a transformation. Unlike methods for dimensionality reduction such as PCA, the resulting signal remains a valid HOA signal and spatial relations are maintained. We present a mathematical framework for space warping, demonstrate the potential of the method using an example, and discuss prerequisites and applications.