In recent years, aiming to enhance and extend user experiences beyond the real world,
Extended Reality (XR) has emerged to become a new paradigm that enables a plethora of
applications [1], eg, online gaming, online conferencing, social media, etc. XR refers to the
human-machine interactions that combine real and virtual environments with the support of
computing/communications technologies and wearable devices. The XR content is
generated by providers or other users, including audio, video and other metadata. In …