ABSTRACT
This chapter describes media sampling clock, system clock and inter-media synchronization methods for multimedia communication and storage systems. As a typical example of multimedia communication systems, it focuses on audiovisual 68communication systems [1] defined by ITU-T Series H Recommendations. It also describes video-on-demand (VOD) systems [2] as a multimedia storage system example. The difference on the clock synchronization methods between communication and storage systems is derived from real-time vs. non-real-time requirements. Multimedia communication systems always require the clock synchronization between a sender and a receiver, while multimedia storage systems do not. A decoder clock can be independent of an encoder in multimedia storage systems. From a clock synchronization point of view, broadcast such as digital TV broadcast can be included in multimedia communication systems. People may classify a broadcasting system under one-way communication systems, but soon it will be enhanced as an asymmetric two-way communication system, when interactive TV systems are widely spread.
