I got my mp4 video to run on all browsers except for Opera. I think it's prejudiced against MP4 videos. I do know it runs the ogg files as I tested one there. Four out of five of my browsers will do the mp4 which is nice.There is a way to present different formats and let the browsers choose. That works pretty well but but I just followed the lesson. By the way, Chrome seems to hate me. I launch my page in Chrome and sometimes it gets this weird dialog asking if I want to kill the page. Nah! Just the browser!