function _validate_custom_formats($input)
 {
     if ($input->value && !movie_tools::formats_string_to_array($input->value)) {
         // Input isn't empty, but doesn't parse correctly - it's invalid.
         $input->add_error("valid_custom_formats", true);
     }
 }
 /**
  * Wrapper around formats_string_to_array() to convert straight to json and handle empty inputs.
  */
 static function formats_string_to_json($input)
 {
     $array = movie_tools::formats_string_to_array($input);
     if ($array) {
         return json_encode($array);
     } else {
         return "";
     }
 }