Playback ends too early
As reported in: http://forum.videolan.org/viewtopic.php?p=218869#p218869
It seems that some H.264 videos inside MP4 container won't normally play till end. Instead the playback ends just little too early. If Next frame button/hotkey is used, the end can be reached. Quicktime plays these files to the end.
Sample file showing the issue: http://www.megaupload.com/?d=9CAXY8QX (the laughter should end and fade to black should be seen)