I think I finally figured out what you are talking about. I can only thank you for your patience!
So, I have demuxed the original file and I have written the script. When I'm watching the file using the script, it seems to work.
Now, my next problem is this: How to I apply the script to my video file? AvsP can only convert to MP4 and Virtual Dub only to AVI. How to I get an MPEG file out of it? And how to I get the audio back into the file?