Say you want a lot of movies on one dvd disc. Which format should you choose? Either wmv or mp4 would work. You can use Handbrake for this.
First, add the repo:
sudo add-apt-repository ppa:handbrake-ubuntu/ppa
sudo apt-get update && sudo apt-get install handbrake-gtk
Then start the application, if it doesn't start, download it here http://handbrake.fr/snapshot.php
Load the source video or dvd into handbrake, make sure it says MP4, and you're set to go.
