How to disable video/audio downloading in web pages?
<p>I have a website that I put my videos/audios on it.
I use HTML5  and  tag to show videos.
But videos/audios can be downloaded if client opens <code>view source</code> page and then copy the file address. 
How can I disable downloading these files, I just want client to see videos/hear audios in the web page.</p>

<p>Many online video/audio services like Youtube disabled downloading videos by this way. How they did that? What is a working way to disable, or at least make this progress much harder?</p>