$re = '/(\[HorribleSubs\])((?P<show>.*?)[ _\-]+)(\((Web|Tv)\)[ _\-]+)?(?P<ep>\d{1,4})(\+(?P<ep2>\d{1,4}))?(v[\d]+)? \[/m';
$str = ' Size
[HorribleSubs] Special 7 - Special Crime Investigation Unit - 02 [1080p].mkv';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php