Power evaluation of 360 VR video streaming on head mounted display devices

Virtual reality (VR) video streaming with 360-degree views has become a trending video application recently. While providing the users with immersive video viewing experiences, the 360 video streaming introduces significantly higher overhead than the traditional 2D video streaming in both bandwidth and power consumption, due to the additional video bytes that must be transmitted and processed. While almost all the prior work in this domain has been focused on the bandwidth optimization, we for the first time investigate the power consequence of VR streaming on head mounted displays (HMDs). In particular, we build an end-to-end VR streaming system using DASH and WebVR technologies, which enables us to conduct empirical power measurements at runtime. In order to uncover the specific power impact caused by VR video streaming, we design eight controlled test cases with various streaming configurations and derive a quantitative power breakdown of the HMD through differential power analysis. Our evaluation and analysis results indicate that the VR streaming overhead accounts for 28.5% of the total power consumption on the HMD, with 18.4% for network transmission of the extra video bytes, 3.6% for the VR video decoding, and 6.5% for the VR view calculation, generation, and rendering. Our research findings quantify the room for improvement in VR video power consumption, based on which, we propose several power optimization strategies aiming to motivate further research in low power VR streaming.