Metadata-Assisted Spatial Audio (MASA) – An Overview

This paper provides an overview of the novel metadata-assisted spatial audio (MASA) format which is one of the supported input formats in the 3GPP IVAS codec. MASA format spatial audio consists of a transport audio signal with one or two channels and parametric metadata describing the dominant directional sound and the diffuseness and coherence properties of the scene. While MASA is mainly intended for parametric spatial audio acquisition from mobile devices, this paper describes a way to determine the parameters from an Ambisonics signal as an example using a widely-available source format. Additionally, the file format for the MASA spatial metadata ingested by the IVAS codec is described. These descriptions are supported by the provided software tools, consisting of a C-Ianguage implementation of the described analysis, and a Python-language library for reading and writing the metadata files.