Energy-Efficient Video Processing for Virtual Reality

Virtual reality (VR) has huge potential to enable radically new applications, behind which spherical panoramic video processing is one of the backbone techniques. However, current VR systems reuse the techniques designed for processing conventional planar videos, resulting in significant energy inefficiencies. Our characterizations show that operations that are unique to processing 360° VR content constitute 40% of the total processing energy consumption. We present EVR, an end-to-end system for energy-efficient VR video processing. EVR recognizes that the major contributor to the VR tax is the projective transformation (PT) operations. EVR mitigates the overhead of PT through two key techniques: semantic-aware streaming on the server and hardware-accelerated rendering on the client device. Real system measurements show that EVR reduces the energy of VR rendering by up to 58%, which translates to up to 42% energy saving for VR devices.