Set Width and Height of HTML5 embedded Video

example:

<video src="http://people.opera.com/shwetankd/webm/sunflower.webm"
 controls autoplay loop> 
<p>Your browser doesn't support WebM format.</p> 
</video> 
<video src="http://people.opera.com/shwetankd/webm/sunflower.webm"
 controls autoplay loop width="320" height="240"> 
<p>Your browser doesn't support WebM format.</p> 
</video>