Abstract. This paper presents the design, implementation and experimental analysis of a distributed, real-time MPEG video and audio player. The player is designed for use across the Internet, a shared environment with variable tra c and with great diversity in network bandwidth and host processing speed. We use a novel toolkit approach to build software feedback mechanisms for client/server synchronization, dynamic Quality-of-Service control, and system adaptiveness. Our experimental results show that the feedback mechanisms are e ective, and that the player performs very well in the Internet environment.