Tvheadend

Tvheadend's configuration is a bit convoluted. For IPTV, first go to the Configuration tab, then DVB Inputs. From there, select the Network tab. Now, create a new IPTV network to hold your streams.

For each IPTV stream/channel you want, it will first need to be defined as its own Mux. Go to the Mux tab, and create a new Mux. When asked for the Network, select the IPTV network you just created. Then, in the URL box, enter the URL for the stream. (Not all streams will work, though. IIRC, Tvheadend will only ingest MPEG-TS streams.) After you create the Mux, Tvheadend will attempt to connect to the stream to discover its Services. After the scan completes (you can either check the log viewer at the bottom of the WebUI, or look at the Scan field in the Mux listing: it should change from Pending, to Active, and then to OK. If it says Failed, then Tvheadend was unable to connect to the stream.)

After the Mux is scanned for Services, go to the Services tab. You should see a Service that is named to match the Mux you just created. Here you can select the option to Map Services to Channels, and Tvheadend will create a new Channel that matches your IPTV stream.

This process can be automated a bit by using the Automatic IPTV Network type, and pre-defining your streams in an M3U playlist. In this manner, you define all of your Muxes, along with optionally giving them readable Service names and channel numbers for Tvheadend.

This ought to get you started, and help explain the process as well as how Tvheadend lays things out to discover how to get things working for your particular setup. Also, there are MANY posts on the forums here about setting up IPTV networks, so check out those for additional pointers.