Practical channel-adaptive video streaming with fountain codes.

"This material is presented to ensure timely dissemination of scholarly and technical work. Copyright and all rights therein are retained by authors or by other copyright holders. All persons copying this information are expected to adhere to the terms and constraints invoked by each author's copyright. In most cases, these works may not be reposted without the explicit permission of the copyright holder.""©2008 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE."Video streaming is sensitive to packet loss, which can severely damage the quality of the received video. Video communication systems that rely on application-layer forward error correction (FEC) to combat packet loss are particularly suitable for pervasive computing because they can be used on top of any existing network architecture. However, since in heterogeneous environments network con- ditions are unpredictable, determining the right amount of redundancy introduced by the channel encoder is not obvious. This paper presents a practical implementation of a unicast video streaming system that solves this problem by using a rateless code and receiver feedback. In real simulations over the Internet our solution outperformed a standard approach based on fixed-rate forward error correction. For an Internet connection Konstanz-Beijing- Konstanz and the standard Foreman sequence compressed with the H.264 video coder, the gain in average peak signal to noise ratio exceeded 3.5 decibels at 90 kilobits per secondShakeel Ahmad was supported by the DFG Research Training Group GK-104