How do you keep the aspect ratio from changing when you import a video ripped into itunes on Windows?

I down load movies from graboid and when i play them on qicktime it stays the same aspect ratio but when i import widescreen videos into itunes it changes to 4:3.How do you keep the aspect ratio from changing when you import a video ripped into itunes on Windows?iTunes only support MP4, H264, Mov video formats. There are some useful guides about how to rip DVD to iTunes and convert videos and TV shows to iTunes for iPod, iPhone, etc, it works well for all the Windows and Mac OS users.

http://www.dvdtoitunes.net/dvdtoitunesvi