Video input...whats out there

I was wondering if anyone has played with or has experience in video input and programming something to display it, in my situation i would like to know how to ge the video from the video input on my graphics card but maybe expand it in the future. is there anything i can use to help me or does anyone have any suggestions on what to look into?

oh and i intend to use win32 api with windows.h in vc to create it.

do you have to use hardware specific programming or is there a generic api that you can use to initialize and what not?