Finally! I found the perfect article to clear up some things on the 4k resolution. In a nut shell both systems will be able to output 4k video, gaming is a VERY far fetch. At most it will be by up-scaling the video and FPS would suffer greatly. At first sony was not even talking much about 4k video support. They finally announced it would. Out of the two systems they would be my best bet at 4k gaming due to the power of the system.
Well Sony has said in no way, shape, or form, will gaming be supported in 4k. So that pretty much eliminates Microsoft as well, regardless of what they say.
Here is the link for any Tech Geeks it is two pages long but clearly explains everything.
Xbox One vs PS4 4k Support