An interactive region-of-interest video streaming system for online lecture viewing

ClassX is an interactive online lecture viewing system developed at Stanford University. Unlike existing solutions that restrict the user to watch only a pre-defined view, ClassX allows interactive pan/tilt/zoom while watching the video. The interactive video streaming paradigm avoids sending the entire field-of-view in the recorded high resolution, thus reducing the required data rate. To alleviate the navigation burden on the part of the online viewer, ClassX offers automatic tracking of the lecturer. ClassX also employs slide recognition technology, which allows automatic synchronization of digital presentation slides with those appearing in the lecture video. This paper presents a design overview of the ClassX system and the evaluation results of a 3-month pilot deployment at Stanford University. The results demonstrate that our system is a low-cost, efficient and pragmatic solution to interactive online lecture viewing.