ENABLING ENERGY-AWARENESS FOR INTERNET VIDEO Oche Omobamibo Ejembi A Thesis Submitted for the Degree of PhD at the University of St Andrews YEAR Full metadata for this item is available in St Andrews Research Repository at: http://research-repository.st-andrews.ac.uk/ Please use this identifier to cite or link to this item: http://hdl.handle.net/10023/9768 This item is protected by original copyright This item is licensed under a Creative Commons Licence Enabling Energy-Awareness for Internet Video Oche Omobamibo Ejembi This thesis is submitted in partial fulfilment for the degree of Doctor of Philosophy at the University of St Andrews August 2016 Abstract Continuous improvements to the state of the art have made it easier to create, send and receive vast quantities of video over the Internet. Catalysed by these developments, video is now the largest, and fastest growing type of traffic on modern IP networks. In 2015, video was responsible for 70% of all traffic on the Internet, with an compound annual growth rate of 27%. On the other hand, concerns about the growing energy consumption of ICT in general, continue to rise. It is not surprising that there is a significant energy cost associated with these extensive video usage patterns. In this thesis, I examine the energy consumption of typical video con- figurations during decoding (playback) and encoding through empirical measurements on an experimental test-bed. I then make extrapolations to a global scale to show the opportunity for significant energy savings, achievable by simple modifications to these video configurations. Based on insights gained from these measurements, I propose a novel, energy-aware Quality of Experience (QoE) metric for digital video - the Energy - Video Quality Index (EnVI). Then, I present and evaluate vEQ- benchmark, a benchmarking and measurement tool for the purpose of generating EnVI scores. The tool enables fine-grained resource-usage analyses on video playback systems, and facilitates the creation of statistical models of power usage for these systems. I propose GreenDASH, an energy-aware extension of the existing Dynamic Adaptive Streaming over HTTP standard (DASH). GreenDASH incorporates relevant energy-usage and video quality information into the existing standard. It could enable dynamic, energy-aware adaptation for video in response to energy-usage and user ‘green’ preferences. I also evaluate the subjective perception of such energy-aware, adaptive video streaming by means of a user study featuring 36 participants. I examine how video may be adapted to save energy without a significant impact on the Quality of Experience of these users. In summary, this thesis highlights the significant opportunities for energy savings if Internet users gain an awareness about their energy usage, and presents a technical discussion how this can be achieved by straightforward extensions to the current state of the art. Relevant Publications Some of the work presented in this thesis has been published. [1] O. Ejembi and S. N. Bhatti. “Help Save The Planet: Please Do Adjust Your Picture”. In: Proceedings of the 22nd ACM International Conference on Multimedia. MM 2014. Orlando, Florida, USA, Nov. 2014. [2] O. Ejembi and S. N. Bhatti. “Towards Energy Benchmarking For Green Video [Extended Abstract]”. In: Proceedings of the 4th IFIP/IEEE Conference on Sustainable Internet and ICT for Sustainability. SustainIT 2015. Apr. 2015. [3] O. Ejembi and S. N. Bhatti. “The Energy Cost of Your Netflix Habit [Poster]”. In: Proceedings of the 6th ACM International Conference on Future Energy Systems. e-Energy 2015. Bangalore, India, July 2015. [4] O. Ejembi and S. N. Bhatti. “Go Green with EnVI: The Energy- Video Index”. In: Proceedings of the IEEE International Symposium on Mulitmedia. ISM 2015. Florida, USA, Dec. 2015. [5] O. Ejembi and S. N. Bhatti. “Client-side Energy Costs of Video Streaming”. In: Proceedings of the 11th IEEE International Conference on Green Computing and Communications. GreenCom 2015. Sydney, AUS, Dec 2015. Acknowledgements First of all, I would like to thank God for His Grace. This has been an incredible journey of learning and self-discovery. I would like to thank my supervisor, Prof Saleem Bhatti for his firm guidance, patience and understanding over the last 5 years, from the day I enquired about undertaking PhD studies as a MSc student, until the submission of this thesis. You will continue to inspire for years to come. I am indebted, almost literally, to SICSA - The Scottish Informatics and Computer Science Alliance who funded my PhD research through a prize studentship. I would like to thank the several people I have lived, worked and studied with over the years here at St Andrews: Dr Chonlatee Khorakun, Hussein Bakri, Bence Szabo, Dr Ditchaphong Phoomkatiskak, Dr Julie Miao, Dr Donglai Mao, Dr Yi Yu, Erezi Ogbo; my fellow “demonstrutors” in the School of Computer Science especially Dr Ruth Hoffman, Adeola Fabola, Dr Saray Shai and Dr Masih Hajiarab Derkani; and all my colleagues at David Russell and Fife Park Apartments especially Dr Lucy Anderson, Ben Stewart, Dr Alexander Griffiths, Dr Helen Cunnold and Dr Michael Pye. You have provided great company on this journey and I am very thankful to have met you. Special thanks to Jim Park, for modifying the Kill-a-watt power-meter I used for my preliminary experiments and the rest of the Systems team: David Letham, Dr Stuart Norcross, and Ross Nicoll for their constant technical support and advice. I thank the various academic staff of the School, who have at various points, given me helpful feedback on my work - Dr Erica Ye, Dr Alan Miller, Prof Simon Dobson and Dr Tristan Henderson. Finally, I would like to thank my parents, Martin and Angela Ejembi, and my sister Ina, for their moral, financial and spiritual support over the years. You are my role models and inspired me to do this. Last but not least, I would like to thank my wonderful wife, Titilope. You are my biggest supporter and motivator, and stand by me through everything. Declaration Candidate’s Declarations I, Oche Omobamibo Ejembi, hereby certify that this thesis, which is approxi- mately 39,000 words in length, has been written by me, that it is the record of work carried out by me and that it has not been submitted in any previous application for a higher degree. I was admitted as a research student and as a candidate for the degree of Doctor of Philosophy in October 2012; the higher study for which this is a record was carried out in the University of St Andrews between 2012 and 2016. Date: Signature of candidate: Supervisor’s Declaration I hereby certify that the candidate has fulfilled the conditions of the Resolu- tion and Regulations appropriate for the degree of Doctor of Philosophy in the University of St Andrews and that the candidate is qualified to submit this thesis in application for that degree. Date: Signature of supervisor: Permission for Publication In submitting this thesis to the University of St Andrews I understand that I am giving permission for it to be made available for use in accordance with the regulations of the University Library for the time being in force, subject to any copyright vested in the work not being affected thereby. I also understand that the title and the abstract will be published, and that a copy of the work may be made and supplied to any bona fide library or research worker, that my thesis will be electronically accessible for personal or research use unless exempt by award of an embargo as requested below, and that the library has the right to migrate my thesis into new electronic forms as required to ensure continued access to the thesis. I have obtained any third-party copyright permissions that may be required in order to allow such access and migration, or have requested the appropriate embargo below. The following is an agreed request by candidate and supervisor regarding the publication of this thesis: No embargo on print copy. No embargo on electronic copy Date: Signature of candidate: Signature of supervisor: To God be the Glory. CONTENTS Contents i List of Figures v List of Tables ix Listings xi Acronyms xiii 1 Introduction 1 1.1 The energy usage of Internet Video . 1 1.2 The potential for growth of Internet Video . 2 1.3 The importance of Internet Video . 3 1.4 Research Motivation and Approach . 5 1.5 Novel Contributions . 5 1.6 Structure and Organisation of the thesis . 6 2 Background - Energy Awareness in ICT 9 2.1 Green ICT: Energy Awareness in ICT . 9 2.2 Green ICT Focus Areas . 11 2.3 Energy-Efficient Hardware . 12 2.3.1 Re-engineering approaches ...................................... 13 2.3.2 Sleeping/Standby approaches . 14 2.3.3 Dynamic adaptation . 14 2.4 Energy-Efficient Software . 16 2.4.1 Energy-efficient algorithms . 16 2.4.2 Energy-aware protocols and applications . 17 2.5 Data centre design, layout, and location . 18 2.6 Server Virtualisation . 20 2.7 Ecolabelling of ICT products and services . 21 2.8 Green Metrics, Assessment Tools and Methodology . 22 2.9 Green Incentives . 23 2.10 Chapter Summary . 23 i II CONTENTS 3 State of the Art: Energy Awareness in Video 25 3.1 Video Diversity . 25 3.2 Internet video ecosystem . 26 3.3 Server-side . 26 3.3.1 Energy usage at the Server-side . 28 3.4 Network . 29 3.4.1 Energy usage at the network . 31 3.5 Client-side . 32 3.5.1 Client-side energy-awareness . 33 3.6 Quality of Experience . 34 3.6.1 Objective Quality Assessments . 35 3.6.2 Subjective Quality Assessments . 37 3.7 Context-Aware Dynamic Adaptation of Video .