What video formats does the iPad support?

I am trying to sync various videos I made on my MAC to my iPAD and some say they are not supported on the ipad. "info" says the accepted ones are mpeg which is fine but the rejected ones are QT files made on iMOVIE. It seems that the ip should accept and play quick time file made with Apple software. What gives? Do I have to change the format on the MAC, and if so, how?