I know that there are many software that you can use to convert files from one format to another, but if you prefer simple and easy-to-use programs that you can use for free, then I can advise you the converter that will
change the dvd extension to MP4 in a few clicks. This tool to change the format of movies and video files is free to use and as far as I know it's one of the best converters. Many people have been using it in their work for many years.