So I created a video using ScreenFlow on a Mac. Then exported it. It created an m4v file. Then I changed the extension to mp4 and tried it out in the following web page:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset=utf-8>
<meta name="viewport" content="width=620">
<title>Fooo</title>
<script src="http://api.html5media.info/1.1.5/html5media.min.js"></script>
</head>
<body>
<video src="Demo.mp4" width="320" height="200" controls preload></video>
</body>
</html>
It does not play. If I move the pointer where the player is it will show the frame at where the pointer is. So all the frames are there but it will just not play the video. What did I do wrong? How do I fix it?
Following @heff's advice, I deleted the script line. Once it was deleted I get this error message: "Video format or MIME type is not supported."
How do I fix this?
.mp4 == .m4v Different extensions for the same container format. Though .mp4 technically is also equal to .m4a, but .m4v != .m4a. At least I'm pretty sure. :)
Sounds like an issue with your javascript library. Have you tried just using the video tag in a browser that supports HTML5 video, with no library? Just delete the script line and see what happens.
Otherwise try posting a link to the live page where we can check it out.