html5 - HTML video player autoplays on firefox but not on Chrome & Safari -

i using code below make video autoplay, loop without controls. http://dustintong.com/projects.html#ts

<div id="video"><video autoplay="autoplay" loop preload="metadata"> <source src="images/7-4s.mp4" type="video/mp4"> 

it autoplays on firefox not on chrome & safari.

try adding ?autoplay=1 end of src:

src="images/7-4s.mp4?autoplay=1"