This special issue comprises some of the outstanding work originally presented at the ACM Multimedia Conference 2003 (ACM MM 2003). The conference received 255 submissions, of which 43 high-quality papers were accepted for presentation. Of these papers, the Technical Program Chairs invited a dozen authors to submit enhanced versions of their papers to this special issue. These papers went through a rigorous review process, and we are happy to present four truly outstanding papers in this special
issue. Due to the highly competitive evaluation process and limited space, many excellent papers could not be accepted for this special issue. However, some of them are being forwarded for consideration as future regular papers in this journal.