A Subjective Study on User Perception Aspects in Virtual Reality

Abstract

Three hundred and sixty degree video is becoming more and more popular on the Internet. By using a Head-Mounted Display, 360-degree video can render a Virtual Reality (VR) environment. However, it is still a big challenge to understand Quality of Experience (QoE) of 360-degree video since user experience during watching 360-degree video is a very complex phenomenon. In this paper, we aim to investigate four QoE aspects of 360-degree video, namely, perceptual quality, presence, cybersickness, and acceptability. In addition, four key QoE-affecting factors of encoding parameters, content motion, rendering device, and rendering mode are considered in our study. To the best of our knowledge, this is the first work that covers a large number of factors and QoE aspects of 360-degree video. In this study, a subjective experiment is conducted using 60 video versions generated from three original 360-degree videos. Based on statistical analysis of the obtained results, various findings on the impacts of the factors on the QoE aspects are provided. In particular, regarding the impacts of encoding parameters, it is found that the difference of QoE is negligible between video versions encoded at 4 K and 2.5 K resolutions. Also, it is suggested that 360-degree video should not be encoded at HD resolution or lower when watching in VR mode using Head Mounted Display. In addition, the bitrate for good QoE varies widely across different video contents. With respect to the content motion factor, its impact is statistically significant on the perceptual quality, presence, and cybersickness. In a comparison of two rendering device sets used in this study, there is no statistically significant difference found for the acceptability and cybersickness. However, the differences of the perceptual quality and presence are indicated to be statistically significant. Regarding the rendering mode, a comparison between VR and non-VR modes is also conducted. Although the non-VR mode always achieves higher perceptual quality scores and higher acceptability rates, more than a half of the viewers prefer the VR mode to the non-VR mode when watching versions encoded at the resolutions of fHD or higher. By contrast, the non-VR mode is preferred at the HD resolution.

Effect of Collaboration Mode and Position Arrangement on Immersive Analytics Tasks in Virtual Reality: A Pilot Study

“…To a large extent, VR can increase the sense of presence and situational awareness [26]. Therefore, it represents an optimal platform to provide unique immersive experiences for users [27,28] and to support sense-making with visualizations [29] and social interaction for group activities. However, its effectiveness depends heavily on how the virtual workspace(s), whether for individuals or the whole group, and collaborative interactions are provided, as a poor design may harm the collaboration and exploratory process [4].…”

On the impact of VR assessment on the Quality of Experience of Highly Realistic Digital Humans

“…Zerman et al [53] presented a behaviour analysis of users interacting with colored volumetric media in a AR application. Tran et al [48] suggested that, in case of evaluating video quality in an immersive setup, aspects such as cybersickness and presence should not be overlooked. Recently, an evaluation of static point cloud contents was conducted in a VR environment [9].…”

Joint effects of depth-aiding augmentations and viewing positions on the quality of experience in augmented telepresence

“…Standardization of streaming 360-degree video is in progress. Recently, Curcio et al [43] have adapted ITU-T 2D and 3D video testing recommendations to 360-degree video in VR HMD, Tran et al [44] have assessed and categorized QoE aspects that affect 360-degree video streaming, and Pérez and Escobar [45] have proposed an assessment-aiding tracking tool for an upcoming ITU-T Recommendation for 360-degree VR video, ITU-T Rec. P.360-VR [46].…”