Regular Expression to search for all known links to YouTube embedded in the HTML document code

youtube_search_regex.php

$re = '~<a\s+(?:[^>]*?\s+)?href=(["\'])(https?:\/\/(?:[0-9A-Z-]+\.)?(?:youtu\.be\/|youtube(?:-nocookie)?\.com\S*?[^\w\s-])([\w-]{11})(?=[^\w-]|$)[?=&+%\w.-]*)\1~ix';
$str = '<a href="http://youtu.be/NLqAF9hrVbY">asd</a>
<a href="http://www.youtube.com/embed/NLqAF9hrVbY">asd</a>
<a href="https://www.youtube.com/embed/NLqAF9hrVbY">asd</a>
<a href="http://www.youtube.com/v/NLqAF9hrVbY?fs=1&hl=en_US">asd</a>
<a href="http://www.youtube.com/v/NLqAF9hrVbY?fs=1&hl=en_US">asd</a>
<a href="http://www.youtube.com/watch?v=NLqAF9hrVbY">asd</a>
<a href="http://www.youtube-nocookie.com/NLqAF9hrVbY">asd</a>
<a href="http://www.youtube.com/user/Scobleizer#p/u/1/1p3vcRhsYGo">asd</a>
<a href="http://www.youtube.com/ytscreeningroom?v=NRHVzbJVx8I">asd</a>
<a href="http://www.youtube.com/sandalsResorts#p/c/54B8C800269D7C1B/2/PPS-8DMrAn4">asd</a>
<a href="http://gdata.youtube.com/feeds/api/videos/NLqAF9hrVbY">asd</a>
<a href="http://www.youtube.com/watch?v=spDj54kf-vY&feature=g-vrec">asd</a>
<a href="http://www.youtube.com/watch?v=spDj54kf-vY&feature=youtu.be">asd</a>
';

preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);

// Print the entire match result
var_dump($matches);