Abstract. Traditionally, the media consumption model has been a passive and isolated activity.However, the advent of media streaming technologies, interactive social applications, and synchronous communications, as well as the convergence between these three developments, point to an evolution towards dynamic shared media experiences. In this new model, geographically distributed groups of consumers, independently of their location and the nature of their enddevices, can be immersed in a common virtual networked environment in which they can share multimedia services, interact and collaborate in real-time within the context of simultaneous media content consumption. In most of these multimedia services and applications, apart from the well-

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-Currently, several media sharing applications that allow social interactions between distributed groups of users are gaining momentum. This paper focuses on a key factor for providing a satisfying feeling of togetherness in those networked scenarios, which is to ensure synchronous playout between distributed users. This research problem is known as Inter-Destination Media Synchronization (IDMS). Particularly, this paper discusses the benefits of extending RTP/RTCP protocols for IDMS purposes. Accordingly, newly defined RTCP messages and control techniques have been added to a previous version of a centralized RTP/RTCP-based IDMS solution to enable an adaptive, highly accurate and standardized solution.Moreover, as different control schemes for IDMS exist, and each one is best suited for specific use cases, our IDMS solution has been extended to be able to adopt each one of them. Simulation results prove the satisfactory responsiveness of our IDMS solution, as well as its consistent behavior when using each one of the deployed control schemes.

As Virtual Reality (VR) applications gain more momentum recently, the social and communication aspects of VR experiences become more relevant. In this paper, we present some initial results of understanding the type of applications and factors that users would find relevant for Social VR. We conducted a study involving 91 participants, and identified 4 key use cases for Social VR: video conferencing, education, gaming and watching movies. Further, we identified 2 important factors for such experiences: interacting within the experience, and enjoying the experience. Our results serve as an initial step before performing more detailed studies on the functional requirements for specific Social VR applications. We also discuss the necessary research to fill in current technological gaps in order to move Social VR experiences forward.