Timeline designs for 360-degree videos in VR
Summary
360-degree videos are video recordings that allow the viewer to see in every possible direction at any moment in time, either with 2D devices such as smartphones and computers, or with head-mounted displays. Interaction with such videos can be challenging. For traditional videos, interaction is commonly done by manipulating playback along the timeline, for example, by pausing, rewinding, fast forwarding, or dragging a slider along a horizontal timeline where the left represents the start and the right represents the end of the video. However, in a fully immersive 360-degree setting created with a head-mounted display, there is no "left" or "right" border, and no upper or lower screen border, making it less obvious where to place a timeline or if such a linear timeline is the most intuitive way for navigating the temporal dimension at all.
Furthermore, 360-degree videos also have a spatial domain, which is why interaction also involves manipulation of the viewing direction, either by manually rotating the video to change the field of view or by turning one’s head into another viewing direction. Especially in the first case, where often horizontal interactions are used, for example by dragging the field of view left or right, this could lead to a conflict with the interaction of a timeline that is also displayed and typically interacted with via horizontal motions.
To deal with this conflict, this project investigates timeline designs different than the common horizontal ones and evaluate their advantages and disadvantages in the context of 360-degree videos experienced with head-mounted displays. In particular, the parameters we explore are timeline shape and orientation. Based on a literature study, we select the most promising designs and parameters and evaluate their usefulness for different tasks and contexts in a comparative user study. Results of our study show interesting insights on each timeline design, however participants' answers and feedback still reflected a clear preference for the standard horizontal timeline, even for 360-degree videos in VR.