Collaborative Research: Redesigning Video Streaming Infrastructure to Systematically Reduce Mobile Device Video Display Energy Consumption in the Video-rich Era

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Abstract: The objective of this research is to develop novel solutions that can systematically reduce the energy consumption of future video-rich mobile devices through re-inventing the entire video streaming infrastructure design. Minimizing display energy consumption is of great practical importance since it accounts for a very high percentage of mobile device energy consumption. The significance of this research is that this is a new holistic approach in which display energy reduction is exploited from the entire streaming infrastructure point of view. Such an approach is a paradigm shift from existing schemes that explore the energy reduction on each mobile device and shall open up new research avenues for video streaming to mobile devices. This high-risk, high-payoff project has broader and transformational impact beyond the research proposed in this proposal. First, this research is well aligned with the grand trend towards cloud-centric information technology infrastructure and will establish a new industrial service direction on architecting future video streaming systems. Second, the developed algorithms, source code, and measurement results will be made available online for public and wide-range usage, benefiting both industrial and academic researchers. Finally, the research training to both undergraduate and graduate students shall produce researchers and engineers with multidisciplinary experience in information technology and computer industries.This research aims at overcoming two fundamental drawbacks of current practice in per-device processing: (1) highly inefficient energy saving from global perspective since the same computation shall be repeated among thousands or millions of mobile devices that receive the same video stream. (2) Non-optimal display energy reduction at device level because the inherent trade-off between saved display energy and the energy needed for additional processing is preventing from adopting sophisticated algorithms. The intellectual merit of this research lies in the development of a paradigm shifting design to move the per-device local processing to data center-based global processing along with the intelligent encoding of the video content for display energy efficient streaming. In particular, two major research directions are carried out in this project. To integrate display awareness into the video streaming infrastructure, display-oriented video processing at data centers is developed first to exploit video source characteristics and different classes of mobile devices in order generate a family of bitstreams, each with embedded parameters for display energy reductions at mobile devices. Then, a context-aware video adaptation at mobile access gateways is designed to transcode the video bitstreams in order to match device viewing environments and wireless channel status for enhanced quality of experience (QoE). To overcome increasing number of video streams leading to significant data storage overhead and degradation of video caching efficiency, a syntax-aware video data deduplication at data centers is investigated to reduce the data storage overhead. Then, a data center assisted universal transcoding at gateways is developed to reduce video cache miss penalty at access gateways. Finally, a solid-state data storage scheme optimized for video caching is designed to fully exploit the potential of using flash memory for video caching.