https://twitter.com/claytravis/status/906613681672396805
I saw this today, and evidently AppleTV TvOS has multicast support, so ESPN can enable this.
Does AndroidTv support this? If not, I'm a bit jealous of AppleTV. If it does, ESPN and others need to implement this.
Not sure this is multicast. Multicast means taking one stream and sharing that between devices (a bit like how broadcast TV works - one signal, lots of people receive it). Multicast tends not to work through domestic ISPs, either - many routers aren't configured to deal with it.
This is either an Apple TV receiving four individual streams and decoding each; or (the way I'd do this) an Apple TV receiving one stream looking like four screens. The bandwidth requirements for four streams simultaneously probably wouldn't be ideal.
Multicast = multiroom sound on Chromecast Audio. (Again, one stream incoming, and sharing that between devices).