Networked Displays for VR Applications: Display as a Service (DaaS)
Stereoscopic Liquid Crystal Displays (LCDs) in a tiled setup, so-called display walls, are rising as a replacement for the classic projection-based systems for Virtual Reality (VR) applications. They have numerous benefits over projectors, the only drawback being their maximum size, which is why VR applications usually resort to using tiled display walls. Problems of display walls are the obvious bezels between single displays making up the wall and, most importantly, the complicated pipeline to display synchronized content across all participating screens. This becomes especially crucial when we are dealing with active-stereo content, where precisely timed display of the left and right stereo channels across the entire display area is essential. Usually, these scenarios require a variety of expensive, specialized hardware, which makes it difficult for such wall setups to spread more widely.
In this paper, we present our service-oriented architecture Display as a Service (DaaS), which uses a virtualization approach to shift the problem of pixel distribution from specialized hardware to a generic software. DaaS provides network-transparent virtual framebuffers (VFBs) for pixel-producing applications to write into and virtual dis- plays (VDs), which potentially span multiple physical displays making up a display wall, to present generated pixels on. Our architecture assumes network-enabled displays with integrated processing capabilities, such that all communication for pixel transport and synchronization between VFBs and VDs can happen entirely over IP networking using standard video streaming and Internet protocols. We show the feasibility of our approach in a heterogeneous use case scenario, evaluate latency and synchronization accuracy, and give an outlook for more potential applications in the field of VR.