The Media Function (MF) is the part of the IPTV environment that provides IPTV and VoIP streaming service. Hereby a IPTV service function supports live TV streaming, PVR and VoD which are delivered over IP unicast. Beside this a general VoIP service offers audio and video call recording and playback (announcement) functionality.

The MF consists of a Java based SIP Media Server (Media Control Function) and media streaming components (Media Delivery Function) controlled by the SIP Media Server.

The Media Control Function is a combination of session and media control. The session control function sets up SIP IPTV sessions (via SIP INVITE, REFER) and the media control function selects the corresponding media delivery or storage function for performing the media streaming (RTP/H.264). The Media Delivery Function is currently realized by a set of TV cards connected to Video LAN Client (VLC) instances. To be more compliant  to upcoming IPTV standards, an RTSP based solution is implemented.

The MS provides a proprietary SIP SUBSCRIBE/NOTIFY based service discovery function which informs the subscriber about available TV channels.