You can edit MP4 files
The big advantage of MP4 is that you can edit your video. It’s easy too. If you have a Windows computer, you should have an editing program called Windows Movie Maker on your hard drive. If you own a Mac, you already have iMovie software on your computer.
You cannot edit a DVD
Years ago, the big electronic companies and movie studios developed a universal standard for the DVD disc. DVDs are encrypted, making it nearly impossible to edit. Why? The movie studios didn’t want folks to make illegal copies or edit the content.