private function convertDuration($rawDuration)
{
$ar = array_reverse(explode(":", $rawDuration));
$duration = floatval($ar[0]);
if (!empty($ar[1])) {
$duration += intval($ar[1]) * 60;
}
if (!empty($ar[2])) {
$duration += intval($ar[2]) * 60 * 60;
}
return $duration;
}