  High Quality Mobile Virtual Reality (VR) is what the incoming graphics
technology era demands: users around the world, regardless of their hardware
and network conditions, can all enjoy the immersive virtual experience.
However, the state-of-the-art software-based mobile VR designs cannot fully
satisfy the realtime performance requirements due to the highly interactive
nature of user's actions and complex environmental constraints during VR
execution. Inspired by the unique human visual system effects and the strong
correlation between VR motion features and realtime hardware-level information,
we propose Q-VR, a novel dynamic collaborative rendering solution via
software-hardware co-design for enabling future low-latency high-quality mobile
VR. At software-level, Q-VR provides flexible high-level tuning interface to
reduce network latency while maintaining user perception. At hardware-level,
Q-VR accommodates a wide spectrum of hardware and network conditions across
users by effectively leveraging the computing capability of the increasingly
powerful VR hardware. Extensive evaluation on real-world games demonstrates
that Q-VR can achieve an average end-to-end performance speedup of 3.4x (up to
6.7x) over the traditional local rendering design in commercial VR devices, and
a 4.1x frame rate improvement over the state-of-the-art static collaborative
rendering.
