Hotspot Interaction in Omnidirectional Videos Using Head-Mounted Displays

Omnidirectional videos (ODVs) -- or 360° videos -- are often viewed using a head-mounted display (HMD), allowing users to look around the scene naturally by turning their head. These videos may be populated with visual markers, hotspots, that can contain additional information of points of interest or provide additional functionality. However, optimal ways for interacting and presenting these hotspots remain unclear. We conducted a 16-participant user study where participants interacted with hotspots with different properties while exploring ODVs. We tested 1) two hotspot activation types, dwell time and fade-in, 2) small and large hotspot icon sizes, and 3) centered and left-edge alignments for the appearing content. We found that a combination of fade-in activation, centered alignment, and large icons generally performs the best, but also that user preferences are diverse. Based on our results, we provide recommendations for optimizing the designs for systems utilizing hotspot interactions with HMDs.