  Interactive audio spatialization technology previously developed for video
game authoring and rendering has evolved into an essential component of
platforms enabling shared immersive virtual experiences for future co-presence,
remote collaboration and entertainment applications. New wearable virtual and
augmented reality displays employ real-time binaural audio computing engines
rendering multiple digital objects and supporting the free navigation of
networked participants or their avatars through a juxtaposition of
environments, real and virtual, often referred to as the Metaverse. These
applications require a parametric audio scene programming interface to
facilitate the creation and deployment of shared, dynamic and realistic virtual
3D worlds on mobile computing platforms and remote servers.
  We propose a practical approach for designing parametric 6-degree-of-freedom
object-based interactive audio engines to deliver the perceptually relevant
binaural cues necessary for audio/visual and virtual/real congruence in
Metaverse experiences. We address the effects of room reverberation, acoustic
reflectors, and obstacles in both the virtual and real environments, and
discuss how such effects may be driven by combinations of pre-computed and
real-time acoustic propagation solvers. We envision an open scene description
model distilled to facilitate the development of interoperable applications
distributed across multiple platforms, where each audio object represents, to
the user, a natural sound source having controllable distance, size,
orientation, and acoustic radiation properties.
