$re = '/(?:musicdb|videodb|special):\/\/(?<Type>albums|tvshows|genres|masterprofile|artists)\/(?:titles\/)?(?<Identifier>[\w\d\-.]+)\/?(?<Season>\d+)?/m';
$str = 'musicdb://albums/2/
videodb://tvshows/titles/1/
videodb://tvshows/titles/1/5/?tvshowid=1
musicdb://genres/2/
special://masterprofile/PartyMode-Video.xsp
musicdb://artists/2/?albumartistonly=false';
preg_match_all($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