get widget id for widget_text filter

How can i get the widget id for the widget_text filter so that I can only apply it to a particular widget instance? Id like to do something like so:

add_filter('widget_text', 'rotate_video_shortcodes');
function rotate_video_shortcodes($text) {

    if ($widget_id == 5) {
        $videos = explode(',', $text);
        shuffle($videos);
        foreach ($videos as $video) {
            do_shortcode('[ytp_video source="'.$video.'"]');
        }
    }else{
        return $text;
    }
}