Odd Request


Trust me, I'm The Doctor.
Would anyone know where I can find a high definition (preferable everything up to 1080p) video card? I don't mean for output, I mean for input into the computer.

My intentions are to have my entertainment center controlled by my computer, which means that all of my devices would be inputted into the comptuer, and put out through dual 512 video cards (one for video output, one for computer functions.. and I know the second card is overkill). I know that the computers can output DVI, which I belive to be naturally high definition, but I want to be able to get the most from my inputs as possible.

So my request is can anyone find me a high definition (I belive it's called a video capture card) input card for PC?