$re = '/{([^{}]*)\|album}/';
$str = '{beethoven|artist}\'s {piano sonata number twenty-three|track}
{bach|artist}\'s {cello preludes|track}
{beethoven|artist}\'s {opus fifty-seven sonata|track}
{bach|artist}\'s {cello preludes|track} performed by {yo-yo ma|artist}
{Bulgarian womens choir|album} ';
preg_match($re, $str, $matches, PREG_OFFSET_CAPTURE, 0);
// Print the entire match result
var_dump($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