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SageTV. Google open-sourced it last year after acquiring it a few years back to be the technology behind their FiberTV offering. Since then, there's been an Android client developed and the backend continues to be developed by a small but dedicated community.
https://play.google.com/store/apps/details?id=sagex.miniclient.android.tv
SageTV
Instructions for Linux
Instructions for BSD/ Freenas/ ETC..
Windows Install is Next, Next, etc.....
Link for Windows
Link for Linux
Play Store