title: htaccess redirect rule without affacting existing directory
body: <p>I need a .htaccess rule that redircts: <a href="http://www.mysite.com/" rel="nofollow">http://www.mysite.com/</a>{username}/{id}</p>
  
  <p>to : <a href="http://www.mysite.com/video.php?username=" rel="nofollow">http://www.mysite.com/video.php?username=</a>{username}&amp;id={id}</p>
  
  <p>The difficulty is that it should not affect the existing directories such as images/ script/ admin/ js/ music/ etc...</p>
  
  <p>(<a href="http://www.mysite.com/images/logo.jpeg" rel="nofollow">http://www.mysite.com/images/logo.jpeg</a>  should not be affeted by this rule)</p>
  
  <p>Any clue ?</p>