State of the Art

Measuring and validating QoE of omnidirectional videos using different HMDs have become increasingly important. The resulting user experience plays an important role in making technology successful and acceptable for a wide user group. The respective “QoE” is defined as the “…degree of delight or annoyance of the user of an application or service…” (P. Le Callet et al. (Qualinet white paper on definitions of quality of experience, in European Network on Quality of Experience in Multimedia Systems and Services (COST Action IC 1003) 3.2012, 2012), ITU–T Rec. P.10/G.100, Vocabulary for Performance and Quality of Service. International Telecommunication Union. Geneva, 2017). One component of QoE is the perceptual media quality of the viewing session, resulting from different technical characteristics of the end-to-end chain comprising the recording, post-processing, representation, coding, retrieval, transmission, playback, and display of 360 \({ }^\circ \) videos. Furthermore, for 360 \({ }^\circ \) video, exploration behavior, presence, and simulator sickness also represent key aspects of QoE. Therefore, besides media quality, these three further constructs need to be assessed for a holistic understanding of QoE in the case of omnidirectional videos.