Sharing video annotations

This paper describes an approach for locating annotations generated in one video and properly placing them in a second, modified version of the same video. We focus on modifications that standard Television (TV) broadcasts may experience, including content insertion and deletion (i.e., commercials), format conversions, and different start/end recording times. To overcome these modifications, we propose content-based video timelines. We identify the position of a frame in a long video stream with an accuracy of one frame based on its content, without using, embedded time codes. To make this approach feasible, we use a compact representation of a video frame which we call a "fingerprint." Fingerprints capture small temporal variations within shots, and therefore allow precise position recovery. Our fingerprints' efficient storage size, extraction time, and comparison complexity suggest that our approach can be applied using off-the-shelf PCs and TV "set-top" boxes.