In this chapter, we present Merge and Forward, an IDMS scheme for adaptive HTTP streaming as a distributed control scheme and adopting the MPEG-DASH standard as representation format. We introduce so-called IDMS sessions and describe how an unstructured peer-to-peer overlay can be created using the session information using MPEG-DASH. We objectively assess the performance of Merge and Forward with respect to convergence time (time needed until all clients hold the same reference time stamp) and scalability. After the negotiation on a reference time stamp, the clients have to synchronize their multimedia playback to the agreed reference time stamp. In order to achieve this, we propose a new adaptive media playout approach minimizing the impact of playback synchronization on the QoE. The proposed adaptive media playout is assessed subjectively using crowd sourcing. We further propose a crowd sourcing methodology for conducting subjective quality assessments in the field of IDMS by utilizing GWAP. We validate the applicability of our methodology by investigating the lower asynchronism threshold for IDMS in scenarios like online quiz games.