如何应用正则表达式来过滤字符串

Question

How can I apply regular expression to filter only

[video src="http://duel.evotechaustin.com/wp-content/uploads/2010/09/kramer.m4v" width="480" height="360" id="b-test" class="player" ] 

from the following string

Is simply dummy text of the printing and typesetting industry. 
[video src="http://duel.evotechaustin.com/wp-content/uploads/2010/09/kramer.m4v"          width="480" height="360" id="b-test" class="player" ]
Lorem Ipsum has been the industry's standard dummy text ever since the 1500s.

or Without using regular expression and Dom is there anyways to get the same

Answer 1

preg_match("/\[video[^\]]+\]/i", $subject, $matches);

$matches[0] contains

[video src="http://duel.evotechaustin.com/wp-content/uploads/2010/09/kramer.m4v" width="480" height="360" id="b-test" class="player"]