Spatial redundancy in Higher Order Ambisonics and its use for lowdelay lossless compression

When Higher Order Ambisonics (HOA) is used to represent a sound field, the channels might contain a lot of redundancy in some cases. This redundancy can be exploited in order to provide more efficient network transmission and storage. In this work the amount of inter-channel redundancy for Higher Order Ambisonics is investigated. Furthermore, lossless compression techniques that build on this redundancy are studied, with a focus on low-delay algorithms for real-time, or two-way, applications. The presented encoding scheme results in a delay of 256 samples, but with a rather high computational complexity both for encoding and decoding. The system also preserves the desired features of the HOA format, such as the scalability and the ability to reproduce over arbitrary loudspeaker layouts.