Developing high-level representations of video clips using video trails

A high-level representation of a video clip comprising information about its physical and semantic structure is necessary for providing appropriate processing, indexing and retrieval capabilities for video databases. We describe a novel technique which reduces a sequence of MPEG encoded video frames to a trail of points in a low dimensional space. In our earlier work, we presented techniques applicable in 3-D, but in this paper, we describe techniques that can be extended to higher dimensions where improved performance is expected. In the low-dimensional space, we can cluster frames, analyze transitions between clusters and compute properties of the resulting trail. Portions of the trail can be classified as either stationary or transitional, leading to high-level descriptions of the video. Tracking the interaction of clusters over time, we lay the groundwork for the complete analysis and representation of the video's physical and semantic structure.