Update on this. With rendered video to my Mac Pro, the QuickTime playback is fantastic with no issues. When it mistaken to another video venue campus, they are saying it looks like it is skipping frames at times. They said they a half-second issue, not stopping but jerky or hesitant in playback. The video is played out of a 3.06 iMac running DVI out to a DVI extender. Cat 5 . Could it be a video card issue on this?