The microelectronics industry has been boosting the capabilities of multimedia mobile devices, but the battery, which is the only power source of most mobile devices, is experiencing relatively slow development. Therefore, determining how to optimize the energy consumption of mobile devices under a predefined performance requirement has become a critical issue. Besides, according to a recent report, tablet and smartphone video consumption grew 35% in the year 2014 and has grown 170% since 2013. Actually, mobile video playback has experienced a significant growth of 2084% from 2011 to 2015. As some of the most energy-consuming tasks, First, I would like to thank my supervisors, Dr. Ángel M. Groba and Eduardo Juárez, for their valuable feedback and support throughout this work. Their support, diligence, and commitment to high-quality research have contributed significantly to this thesis. I am also grateful to all the professors and lab mates in GDEM-CITSEM: César Sanz, Matías J. Garrido, Fernando Pescador and Pedro J. Lobo, for their efforts in providing and creating such a friendly and helpful working environment in the lab. Thanks also to my colleagues: Rong Ren, Jianguo Wei, Henry O. Cruz and Miguel Chavarrías. I have learned a lot from each of them; our friendships have made my time at GDEM an enjoyable and unique experience. Thanks to Paula and Enrique, I have benefited a lot through the cooperation and the exchange of ideas with them. Finally, I would like to acknowledge and appreciate the financial support from China Scholarship Council (CSC) and GDEM. Besides, I would like to express my love and appreciation to my parents. Thanks for them to bring me up and support good quality of education for me. During these years, I met difficulties and setbacks that taught me to grow and hone my character. I benefit from the doctoral stage of study, and no matter where I work in the future, I will keep a serious and focused researcher, and strive to do everything for the community to contribute to their own strength. I would like to thank all my friends: Rong Ren,