if (preg_match('/((\w+)(MidRes|LowRes))\.php/U', $id, $matches))
{
   $santised_filename = mysql_real_escape_string($matches[2]);
   $sql = "SELECT mime_types.extension, mime_types.mime_type
           FROM mime_types, quicktime_demos
           WHERE quicktime_demos.shortname = '$santised_filename'
           AND mime_types.id = quicktime_demos.mime_type";
   $result = mysql_query($sql)
      or
      die("Query failed (demos): " . mysql_error());

   $row = mysql_fetch_array($result);

   if ($row) {
      $filename = $matches[1].'.'.$row['extension'];
      header('HTTP/1.1 200 OK');
      header("Content-Type: {$row['mime_type']}");
      header("Content-Length: ".filesize($filename));
      header("Content-Disposition: attachment; filename=$filename");
      readfile($filename);
      exit();
   }
}