just called 360 about this and found out that the same thing happens if you play a workable video for the xbox 360 video library, it does the same thing. takes off from OAR.
apparently if you play video from a PC to the 360 wireless or wired the xbox will change the OAR. This is for the white xbox. I don't know about the new black ones but this is a real problem nobody notices!! that is serious imo
. this is stupid because i'm pretty sure if you insert a dvd to a 360 it will play it without messing with the aspect ratio unless you do a change. same thing with buying videos in the marketplace and zune. I still need to see if i add a video into the 360 HD or plug in a usb with a video , if it will work but i doubt it.