protected function set_videos()
 {
     if (isset($_GET['external_video_provider_id']) && isset($_GET['tag_ids'])) {
         $videos = VideoLibrary_DatabaseHelper::get_external_videos_for_tag_ids_and_external_video_provider_id($this->get_external_video_library_id(), $this->get_tag_ids(), $this->get_external_video_provider_id(), NULL, $this->get_start(), $this->get_duration());
     } elseif (isset($_GET['external_video_provider_id'])) {
         $videos = VideoLibrary_DatabaseHelper::get_external_videos_for_provider_id($this->get_external_video_library_id(), $this->get_external_video_provider_id(), $this->get_start(), $this->get_duration());
     } elseif (isset($_GET['tag_ids'])) {
         $videos = VideoLibrary_DatabaseHelper::get_external_videos_for_tag_ids($this->get_external_video_library_id(), $this->get_tag_ids(), NULL, $this->get_start(), $this->get_duration());
     } elseif (isset($_GET['q'])) {
         $videos = VideoLibrary_SearchHelper::get_external_videos_for_search_string($this->get_external_video_library_id(), $this->get_search_string(), $this->get_start(), $this->get_duration());
     } else {
         $videos = VideoLibrary_DatabaseHelper::get_external_videos($this->get_external_video_library_id(), $this->get_start(), $this->get_duration());
     }
     $this->videos = $videos;
 }