TNO TNO TNO Universitat Politecnica de Universitat Politecnica de [RFC7272] describes the use of RTCP for the purpose of Inter- Destination Media Synchronization (IDMS) between Synchronization Clients (SCs) and an Media Synchronization Application Server (MSAS). This document extends that work for application in the area of IPTV. First, RTCP can be used according to the single source multicast (SSM) principles from [RFC5760] in the IPTV application area. This document specifies the use of a feedback target for collecting and possibly summarizing IDMS reports. For this, the document defines 2 new sub-report blocks for the use of IDMS according to the SSM principles. Alternatively, the MSAS can be co-located with the Feedback Target, for synchronizing small groups of receivers. Secondly, in an IPTV environment, different viewers may receive the same content, but in non-identical streams. The IDMS solution presented in [RFC7272] will no longer work in such a case. This document provides a solution for this.