This Recommendation categorizes and summarizes the factors affecting the user-perceived experience of a virtual reality (VR) service, with the intention of helping to identify the methodologies for assessing VR quality. VR quality of experience (QoE) assessment methodologies are left for further study. Since VR technologies are still evolving, this Recommendation mainly addresses omnidirectional video services, while leaving others, e.g., point-cloud or volumetric video types, for further study.

VR is a new type of media which is different from traditional video and audio. It generates realistic images, sounds and other sensations that replicate a real environment and simulate a user's physical presence in this environment by enabling the user to interact with this space and any objects depicted therein using specialized display screens or projectors and other devices. These multisensory experiences, which can include sight, hearing and, less commonly, touch and smell, are well coordinated and synchronized through the user's interaction and feedback. A person using VR equipment is typically able to "look around" the artificial world, move about within it and interact with features or items that are depicted on a screen or in goggles as in the real world.

In order to understand whether QoE or user-perceived performance of the VR service is good enough or not, benchmarking is critical. Benchmarking aims to measure user-perceived performance or QoE in the VR environment. Compared with traditional video and audio, the multisensory experience in VR imposes a new set of requirements for QoE assessment. The challenge is to characterize VR's real-life immersive video, spatial audio and interactivity. Prior to being able to benchmark the QoE, it is important to address the requirements and basic factors that are relevant for assessing the VR quality for different VR services.