You Only Render Once:
Enhancing Energy and Computation Efficiency of Mobile Virtual Reality

Mobile Virtual Reality (VR) is essential to achieving convenient and immersive human-computer interaction and realizing emerging applications such as Metaverse. However, existing VR technologies require two separate renderings of binocular images, causing a significant bottleneck for mobile devices with limited computing capability and power supply. This paper proposes an approach to rendering optimization for mobile VR called You Only Render Once (YORO). By utilizing the per-pixel attribute, YORO can generate binocular VR images from the monocular image through genuinely one rendering, saving half the computation over conventional approaches. Our evaluation indicates that, compared with the state-of-art, YORO can save 27% power consumption on average while achieving high binocular image quality (0.9679 SSIM and 34.09 PSNR) in mobile VR applications. Additionally, YORO can increase the frame rate by 115.2%. These results corroborate YORO's superior computation/energy-saving performance, paving the road to a sustainable mobile VR.

• YORO is a general optimization technique compatible with OpenXR frameworks, supporting various COTS VR devices such as Meta Quest, HTC Vive Focus, Pico Neo, Apple Vision Pro and more.
• YORO is production ready and can be directly applied to the Unity engine to support various VR games and applications.
• YORO can serve as a cornerstone and be integrated with other optimization techniques such as Foveated Rendering and Asynchronous TimeWarp to further enhance the performance of VR applications.