Ultra-Low Delay Lossless Compression of Higher Order Ambisonics

Abstract

Coding delay has emerged as a significant obstacle to wider adoption of Higher Order Ambisonics (HOA), a promising flexible format employed in representation and coding of spatial audio. Low delay is critical in many applications, such as virtual reality, gaming, and online music performance, a good subset of which further require lossless compression. However, major advances in spatial audio codec design often sacrifice low delay in order to maximize compression gains. We present a new lossless, ultra-low delay HOA codec, optimized to take advantage of both the spatial and temporal redundancies in HOA data, while maintaining an extremely low delay. The presented codec has an algorithmic delay of one single sample, at the cost of increased computational complexity. This codec outperforms the state-of-the-art for lossless, low-delay HOA coding, both in terms of delay and bitrate.