The ones that replace your normal video card don't though Basically instead of just having somewhere to plug the monitor to send signals out, it also has somewhere to plug a TV or other video device to. I think they normally come with software to let you capture, but having not got one of these myself, I'm not sure In any case, VirtualDub can capture and encode once you have a video capture device of some sort, and I'm sure there's other free software that can do that too