Offloading-based Power-Efficient Mobile VTuber Live Streaming

Virtual YouTuber (VTuber) live streaming, which renders and streams a virtual avatar of the actual streamer on top of the live camera view, has gained significant popularity recently. Despite the engaging user experience, the intensive and power-consuming computations required by VTuber applications, such as facial feature extraction and avatar rendering, pose significant challenges to the constrained battery life of mobile devices. We develop a power-efficient VTuber live streaming system by offloading the camera view and the computation-intensive operations from the mobile device to an edge server. Our approach not only reduces the power consumption of the mobile device but also enables larger-scale rendering of multiple avatars, which is infeasible in existing mobile VTuber systems. Furthermore, to reduce the bandwidth overhead caused by the camera view offloading, we develop an adaptive framerate control mechanism to dynamically adjust the framerate of the offloaded camera view based on the variations of inter-frame luminance, as well as resolution control to dynamically adjust the resolution of the offloaded camera view based on the number and size of the faces. Our evaluations on the end-to-end VTuber live streaming system demonstrate 26%-29% power savings with limited latency, bandwidth, and quality overhead.