XRgo: Design and Evaluation of Rendering Offload for Low-Power Extended Reality Devices

Steven Gao, Jeffrey Liu, Qinjun Jiang, Finn Sinclair, William Sentosa, Brighten Godfrey, Sarita V. Adve

Abstract: Extended reality (XR) devices must render high-quality 3D graphics at low latency to deliver truly immersive experiences. However, XR devices are severely power- and resource-constrained, limiting the quality of on-device (local) rendering. Offloading rendering to a powerful remote machine can enhance graphics quality, but network latency can degrade the overall experience. To mask latency, XR systems reproject the rendered frame to compensate for user motion since the rendered pose. Traditional reprojection, known as TimeWarp, uses a lightweight mechanism to compensate for latency in rotational motion, but not translational motion. Compensating for translational motion is more expensive, but is increasingly important at higher latencies.We present XRgo, the first open-source XR runtime that supports application-transparent offloading of rendering to a remote server with client-side six-degrees-of-freedom (6-DoF) reprojection. XRgo uses OpenWarp, the first open-source and OpenXR-compatible lightweight 6-DoF mesh-based reprojection technique. Compared to on-device rendering, XRgo consistently renders at the target frame rate while consuming less power. User studies show that on average, OpenWarp provides a superior XR experience than TimeWarp. Further, OpenWarp only consumes < 2% more power than TimeWarp. Our findings reveal that the quality of experience depends on both network average latency and variability, highlighting the need for end-to-end evaluations under live network conditions.

External IDs:dblp:conf/mmsys/GaoLJSSGA25