Tvheadend

TVheadend 4.1.2415 is not able to receive IPTV multiplexes which are delivered via SSM (source specific multicast) due to missing implementation of the IGMP v3 protocol (IGMP v2 is implemented!). For example, the SSM is applied in the newer release of the IPTV-service of Deutsche Telekom (EntertainTV). The older ASM (any source multicast) service (Entertain)will be stopped in the future.
Would be a great thing if you could introduce IGMP v3 for SSM in a future release!

SSM uses stream URLs of the type

rtp://{IP adress of source}@{IP adress of requested multiplex}:{port number}

The multiplex can be received in TVheadend via the pipe

pipe:///usr/bin/ffmpeg -loglevel fatal -i rtp://{IP adress of requested multiplex}:{port
     number}?sources={IP adress of source} -codec copy -f mpegts pipe:1

Unfortunately, the ffmpeg pipe is to slow for HD Services on a Rapsberry PI3. However, the IGMP v3 implementation in ffmpeg could give a hint in which manner things can be handled: Function "udp_set_multicast_sources()" implements the joining to a multicast group with IGMPv3 calls:
http://github.com/FFmpeg/FFmpeg/blob/415f907ce8dcca87c9e7cfdc954b92df399d3d80/libavformat/udp.c#L280
(Thanks to user Mono Polimorph, again!)