Has this ever happened to anyone? Using Premiere 6.5 when laying a clip on video 2 over video 1 to composite the two (with transparency) the result (after rendering) plays fine for a few seconds, then jumps & stutters. If both clips have the sound unlinked & deleted, it still happens. This is seriously hampering my creativity. Can't find any troubleshooter or help index that mentions it. Can anyone suggest what's happening?