$re = '/^.+?(?=\s*[(.]?(\d{4}))/mi';
$str = '
Birdman.2014.DVDSCR.X264-PLAYNOW.mkv
Divergent (2014) 720p Blu-Ray x2649 [Dual-Audio][English DD 5.1 + Hindi DD 5.1] - Mafiaking - TeamTNT ExClusive.mkv
Cradle 2 The Grave 2003 HDTVRip 720p Dual-Audio[Eng+Hindi] ~ BRAR
';
preg_match_all($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