The Pacific-Rim Conference on Multimedia (PCM) was held in Hong Kong, at the City University of Hong Kong, during December 11-14, 2007. Started in 2000, PCM has been held in various places around the Pacific Rim, including Sydney, Beijing, Hsinchu, Singapore, Tokyo, Jeju, and Zhejiang in chronological order. PCM is a major annual international conference organized as a forum for the dissemination of state-of-the-art technological advances and research results in the fields of theoretical, experimental, and applied multimedia analysis and processing. PCM 2007 was organized into 5 different tracks with a total of 247 submissions from 26 countries and regions including Australia, Belgium, Canada, China, Japan, Korea, New Zealand, Singapore, Spain, Taiwan, the UK and the USA. Among the five tracks, "multimedia analysis and retrieval" received the most number of submissions (34% of the submissions). After a rigorous review process, 73 papers were accepted for oral presentations, giving an acceptance rate of under 29% for PCM 2007. In addition, 21 papers were accepted for poster presentations. We would like to thank all the Track Chairs and the reviewers for their timely handling of the paper reviews. We are particularly grateful to Chong-Wah Ngo and his team for their support of the Web-based review system throughout the process. We are also indebted to the Special Sessions Chairs, Qi Tian and Timothy Shih, for the organization of the two special sessions on "The AVS China National Standard" and "Multimedia Information System for Biomedical Research," respectively.