Let's say I have a 120 frame MPG, and I want to erase frames 1-29, 31-59, 61-89, 91-129, so I'm left with frames 30, 60, 90, and 120. I remove the audio, but don't know what to do to remove the frames. I could do this with VirtualDub, but the problem shows up when I have a 120,000 frame video and can't manually delete each section. I want the end result to be a time-lapse video... so if I film a 6 hour MPG, I can remove enough frames to be left with a 1 minute time lapse video. What's the best way to do this?