One of the key issues in streaming video over the Internet or wireless channels is to effectively adjust the bit rate adapting to the dynamics of available channel bandwidth and at the same time maintaining the highest possible and stable video quality with good coding efficiency. The recent ISO MPEG-4 AVC (advanced video coding) or ITU-T H.264 standard provides substantial improvements to coding efficiency for video transmission.
Our research focuses on designing algorithms for effective control of sending rate adaptive to available channel bandwidth. The adaptive bit rate control is based on a fluid-flow traffic model and a revised quadratic rate-distortion model. Our method also gives heavier weights to earlier predictors in the picture sequence to achieve a better overall quality. Moreover, we reduce video distortion, due to high motions or scene changes, by more accurately predicting frame complexity using the statistics of previously encoded frames in comparison with that of the current frame. Our recent results also include an improved frame skipping decision scheme to reduce the number of forced skipped frames that can cause poor reconstruction of video and motion jerkiness associated with the skips. The proposed bit rate control scheme is optimized for video quality, especially at low bit rates.
Comparing to other existing schemes, our method allocates bits better to adapt to the dynamics of channel bandwidth. It effectively alleviates visual quality (PSNR) variation and significantly reduces the number of otherwise forced skipped frames. The overall visual quality value (PSNR) is also slightly improved. Part of the project was conducted jointly with the Institute for Infocomm Research, A*STAR, Singapore.
Prof Ling is currently an Associate Dean of Engineering and a full Professor of Computer Engineering. He was named 2002-2003 IEEE Distinguished Lecturer by the IEEE Circuits and Systems Society, and an Honorary Advisor to the National University of Singapore.
His research interests are in the fields of video coding, video streaming, and MPEG-2/MPEG-4/H.264 video decoder architecture. He has about 100 research publications, including a book on systolic arrays. Prof. Ling was named Arthur Vining Davis Junior Faculty Fellow in the U.S. in 1991-92. He received the SCU Outstanding Achievement Award in Teaching, Research, and Service, in 1992, and was named Researcher of the Year by SCU in 2000. In 2002, Prof. Ling also received the SCU Award for Recent Achievement in Scholarship.
Prof. Ling has served as an Associate Editor for the IEEE Transactions on Circuits and Systems-I, and was the Chair and members of the IEEE Technical Committee on various subjects in various societies, including computer society. He was general/program/session Chairs for many IEEE conferences; he is a well recognized scholar in his fields.
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