Recently I had some legacy hardware applications that required a multicast heartbeat back to clients on the same wifi network. These were specialized tools from GM that technicians used to connect to vehicles for diagnostics back to GM. GM calls them the MDI (Multiple Diagnostic Interface).
I had a problem using Ubiquiti Unifi controller stable (2.4.6 at the time of writing). Apparently, it doesnt allow IGMP Snooping to be disabled (or at least I could not for the life of me figure it out). I did find a little FAQ from the admins that shows the process of doing this, although this is not terribly documented anywhere clearly.
You need to be running the BETA version of the controller (puts you up into v3.x[3.1.9 at the time of writing])
I was running stable v.2, so I did this on my Ubuntu box (dont worry, Ubiquiti is nice enough to save settings):
sudo apt-get remove unifi sudo apt-get update sudo apt-get install unifi-beta
You use vi to create a file in the [UniFi base]/data/sites/the_site called config.properties.
vi /usr/lib/unifi/data/sites/default/config.properties config.igmpsnoop_enabled.[ssid]=false
You reboot that server, and enjoy multicast.