Ok, lets try this. I'm not quiet sure what exactly is stored in your database in image_duration, but I'll assume it stores time in seconds, so if video duration is 4:27 in the database it stored number 267 and not huge timestamp number.
In search.php find:
if (!empty($search_id)) {
Insert above:
if (isset($HTTP_GET_VARS['image_duration']) || isset($HTTP_POST_VARS['image_duration'])) {
$image_duration = isset($HTTP_POST_VARS['image_duration']) ? trim($HTTP_POST_VARS['image_duration']) : trim($HTTP_GET_VARS['image_duration']);
}
else {
$image_duration = 0;
}
### convert string into seconds. asuming string format is h:m:s (also accepted m:s or simply s)
$t = explode(":", $image_duration);
$c = 3-count($t);
for($i = 0; $i < $c; $i++) array_unshift($t, 0); ### make sure array has at least 3 values
$c = count($t);
$image_duration = gmmktime(intval($t[$c-3]), intval($t[$c-2]), intval($t[$c-1]), 1, 1, 1970); ### this will return number in seconds.
if ($image_duration && $show_result == 1) {
$search_id['image_duration'] = $image_duration;
}
if (!empty($sql_where_query)) {
Insert above:
if (!empty($search_id['image_duration']))
{
$sql_where_query .= "AND image_duration >= ".$search_id['image_duration'];
}