Kodi, formerly known as XBMC is excellent free and open source software for all your media centre needs (and especially video).
They have a community forum where they have complied a FAQ on hardware for 4K. It’s a short FAQ because the hardware availability for 4K just isn’t there yet. We expect 2016 to be a much better year for video cards in regards to supporting 4K standards.
A valuable quote from the FAQ:
In the past 10-bit colour encoding was meant for professional use but in HEVC it’s part of the Main10 profile so it will be part of consumer applications. It’s expected to be used in UHDTV broadcasts (Rec. 2020), Blu Ray and Netflix. So, in order to future-proof yourself it’s good to have a box that supports the main10 profile.
The FAQ and replies are worth a read for anyone thinking of building a future-proof home theatre PC.