if( ! function_exists( 'videotube_mars_main_widget_args' ) ){
    function videotube_mars_main_widget_args( $args ) {
        $args['post_type'] = array( 'post','video' );
        return $args;
    }
    add_filter( 'mars_main_widget_args' , 'videotube_mars_main_widget_args', 10, 1 );
}