Fast Bitstream Switching Algorithms for Real-Time Adaptive Video Multicasting

Bitstream switching among multiple bitstreams encoded at different bit rates is an effective way to address the bandwidth variation issue in transmitting multimedia over the Internet or wireless networks. This paper proposes two new fast real-time bitstream switching algorithms that aim to minimize the drifting error, while avoiding the problems of long delay, high complexity and bit-rate overhead for storage and transmission that often occur in prior solutions. The basic idea is to choose a switching point in a neighborhood with the highest encoding quality, within a switching window determined by the switching delay constraint. We show that they can significantly outperform a simple switching algorithm, and achieve performance that is closer to an offline mean-square-error-optimized bitstream switching solution, when compared to our previous work based on the similarity of the reference frames. The proposed schemes are especially useful in the scenario of real-time multicasting over dynamic heterogeneous networks, where multiple bitstreams with different bit rates are generated on the fly and dynamic bitstream switching is required for individual clients