From IPTV to synchronous shared experiences challenges in design: Distributed media synchronization

Recent developments on Social TV point to an evolution from traditional IPTV services towards more social experiences. Newer applications and services have appeared wherein groups of people in different locations can watch multimedia content while synchronously communicating with each other. We name such applications as synchronous shared experiences. Realization of these shared experiences requires that users feel that they are coherently communicating with each other. This paper identifies and analyzes challenges that need to be tackled to achieve coherence: quality of service, mobility and distributed media synchronization. Furthermore, universal session handling is required to setup these sessions. We then present our solution to one of these challenges: distributed media synchronization. Our design uses the local lag mechanism over a distributed control or master–slave signaling architecture. We validate our implementation via experiments performed with one client located in Amsterdam and the other in Seoul. The experiments demonstrate a bound in play-out skew of 500 ms across these locations. Our results from user tests, presented elsewhere, show that this value is well within tolerance limits.