1. National Engineering Research Center for Multimedia Software, School of Computer Science, Wuhan University, Wuhan, China
2. School of Cyber Science and Technology, Sun Yat-sen University, Guangzhou, China
3. College of Computer Science and Technology, Hangzhou Dianzi University, Hangzhou, China
4. Department of Electrical Engineering and the Institute of Communications Engineering, National Tsing Hua University, Hsinchu, Taiwan