I want to correct the first person to answer, it is not illegal to copy the DVD into your computer when you have the original, it will only be illegal when he sends it to other people and shares it to other people.
Use a program to extract the DVD, most likely this program would have options on the format. Just google for the software.
You can use iOrgsoft DVD ripper------a DVD ripping tool to rip your favorite DVDs to popular MP4, AVC (H.264), AVI (Divx, Xvid), WMV, MOV, MPEG 1, MPEG 2, MPEG 4, 3GP, FLV, SWF files. The all-in-one DVD Ripper also allows you to extract DVD audio to MP3, WAV, WMA, AAC, AC3, AMR, M4A, MP2, AIFF and FLAC format. With DVD Ripper, you can enjoy DVD movies on personal portable devices, including iPod, iPhone, Apple TV, PSP, Zune, BlackBerry, GPhone, and other MP3/4 players.