I am using a Windows XP and i have quicktime Pro, Whenever I download a music video to put on my iPod it works fine on the computer when viewing as a mpeg file in windows media viewer, but after i export it using quicktime pro to change it to an mpeg4 format so i can put it onto my iPod, i lose the sound when i view it as the new format on the computer or the ipod. Pls Help.