<?

$regexp="/https?:\/\/(?:[0-9A-Z-]+\.)?(?:youtu\.be\/|youtube\.com(?:\/embed\/|\/v\/|\/watch\?v=|\/ytscreeningroom\?v=|\/feeds\/api\/videos\/|\/user\S*[^\w\-\s]|\S*[^\w\-\s]))([\w\-]{11})[?=&+%\w-]*/i";
$url="http://youtu.be/NLqAF9hrVbY";

$result=preg_match($regexp,$url,$matches);

if ($result)
{
echo $matches[0];
}



?>