HTML5 - How to stream large .mp4 files?

I'm trying to setup a very basic html5 page that loads a .mp4 video that is 20MB. It appears that the browser needs to download the entire thing rather than just playing the first part of the video and streaming in the rest.

This post is the closest thing I've found while searching... I tried both Hand Brake and Data Go Round by neither appeared to make a difference:

Any ideas on how to do this or if it's possible?

Here is the code I'm using:

<video controls="controls">
    <source src="/video.mp4" type="video/mp4" />
    Your browser does not support the video tag.
</video>

Solution

Ensure that the moov (metadata) is before the mdat (audio/video data). This is also called "fast start" or "web optimized". For example, Handbrake has a "Web Optimized" checkbox and ffmpeg has the output option -movflags faststart.
Ensure that your web server is reporting the correct Content-Type (video/mp4).
Ensure that your web server is configured to serve byte range requests.
Ensure that your web server is not applying gzip or deflate compression on top of the compression in the mp4 file.

You can check the headers being sent by your web server using curl -I http://yoursite/video.mp4 or using the developer tools in your browser (Chrome, Firefox) (reload the page if it is cached). The HTTP Response Header should include Content-Type: video/mp4 and Accept-Ranges: bytes, and no Content-Encoding:.