Murat Tekalp
University of Rochester
 
A Position Statement for Panel 2: Video representation, coding, indexing
   The 1998 International Workshop on Very Low Bitrate Video Coding
 
 
Video representations for compression evolved from pixel-based to block-based to object-based as digital video applications grew more sophisticated. While block-based representations prove sufficient for the purposes of compression efficiency, they are blind to content; and hence, do not allow content-based interactivity. Object-based representations allowed by VRML and MPEG-4 enable more sophisticated content-based interactivity, such as tuning of compression parameters to each object, composition of content from various sources, and object-based manipulation of content. Together with temporal hierarchies, such as scenes and shots, we are now better equipped for  content-based video abstraction. However, the state of the art in multimedia signal processing and computer vision precludes the possibility of a high level abstraction fully automatically. In order to advance the state of the art, we need to address the following questions: are the presently known representations for visual objects sufficient for content-based abstraction? How much can be done automatically? What kind of interactive tools are needed to facilitate semi-automatic video abstraction? Can effective video abstraction be coupled with compression methods to improve compression efficiency?