This feature should be the option of "Skip a file if it already has all required pictures on the disk (BE CAREFUL)." but renamed to something more user friendly of course. If a filename already exists for the one VTM is trying to make, then just skip the video. It should be an easy solution.
I totally agree with you. It is a very useful feature for whole directories. I actually came to the forum just to request it and found somebody else did it already.