HTML 5 Issues.
I've been testing the html5 since your script supports that format but i found some issues. First if you open videos in succession and have the autoplay off then some videos wont not autoplay but some others will. Also those videos that do not autoplay you dont see them playing but you can hear the sound as if they were wich is very bothersome cause even if you go to the video and put play then pause it wont stop.
I've encounter this bug before (I thought I've fixed it in an earlier version). I'll try to fix it (again).