Energy consumption anatomy of live video streaming from a smartphone

Smartphones are frequently used to shoot and share videos online and emerging applications, such as Augmented Reality, will increase the usage of the camera. Unfortunately, shooting and streaming video drains a modern smartphone´s battery very quickly. We report results from a measurement study to dissect the smartphone energy consumption when using such an application. Our main findings are that the majority of power is drawn already when the camera is in focus mode and not yet recording. This power is drawn by the camera internal hardware and some other hardware of the smartphone related to the video processing, and none of this hardware seems to scale the power draw with the video resolution or bit rate. We also study the effectiveness of two simple optimization techniques, namely frame bundling to optimize the radio usage and more aggressive frequency and voltage scaling to reduce the computational power draw. We conclude that while the mechanisms are effective, their potential is overshadowed by the large power draw of other hardware.