Generalised Transcoding Framework for Arbitrary Spatial Audio Capture and Playback Formats
This work addresses the problem of flexible spatial audio reproduction for diverse capture and playback systems, offering a generalised solution that improves perceived quality in constrained scenarios.
The paper introduces a unified parametric framework for transcoding spatial audio between arbitrary capture and playback formats, including Ambisonic and raw microphone arrays. Listening tests show perceptual benefits over existing methods, especially for lower-order and constrained arrays.
This article introduces a unified framework for the parametric analysis and reproduction of spatial sound scenes captured either as Ambisonic signals or as raw microphone array signals. The proposed method estimates time-frequency-dependent spatial metadata that characterises a variable number of primary source components and an ambience component with its own angular power distribution, whose parameters fit the observed spatial covariances of the captured signals. This metadata is used to construct spatial covariances of the target playback formats, which are then used to derive optimal mixing matrices for transcoding the scene for playback over the target reproduction system. The method additionally handles independent rotations of both capture and playback setups. Real-time implementations of the method and other existing state-of-the-art parametric renderers are compared in a listening test using simulated scenes from Ambisonic, spherical, and head-worn arrays. The results highlight perceptual benefits of the proposed framework across a diverse range of content and receiver configurations, particularly for lower-order and geometrically constrained microphone arrays.