I've downloaded an asf streaming video with vlc player at home and converted it to mp4. It plays fine at home (windows media player). It also plays fine at work on a Apple Tiger 10.4 with VLC Player. When I play it on Quicktime 7.6.4 however, the playback is jerky sometimes. Also the sound isn't always in sync with the images. Why is that? I've also tried it with two dvd's I've ripped on this Mac with 4media dvd ripper and converted to mp4 in the process. They play fine in VLC player on the Mac, but there's this jerky playback and out of sync audio. Other formats, like avi or mov play fine in Quicktime. Can someone explain why my Quicktime has trouble playing mp4 files?