Playing a movie on the computer and re-recording it at the same time.

I have many old overseas movies which come with subtitles in
files, or selectable subtitles from the menu in the player
software such as "VLC" media player.

I can get these to play OK on the computer, though it is
hard to burn them to DVD/XVid with the subtitles of my
choice imbedded in the image.

Therefore I ask:

When I play these movies on my computer, can I channel the
output video to another file on the HDD, which will then
have the movie recorded as I want it?

That is; since the movie is being played on the computer
screen, is there someway to parallel this to a separate file
on the HDD?

I have an nVidia video card installed with an S-Video out
connection.

I also have a "Compro" TV card installed.

Please help, I'm desperate:

PJ