FlaviaS

This was my solution ( on functions.php):

add_filter( 'pre_get_posts', 'my_get_posts' );

		function my_get_posts( $query ) {

			if ( ( is_category () && $query->is_main_query() ) || is_feed() )
			$query->set( 'post_type', array( 'post', 'video' ) );

		return $query;
		}

Here is my Function.php:

function search_excerpt_highlight() {
    $excerpt = get_the_excerpt();
    $keys = implode('|', explode(' ', get_search_query()));
    $excerpt = preg_replace('/(' . $keys .')/iu', '<strong class="search-highlight"></strong>', $excerpt);

    echo '<p>' . $excerpt . '</p>';
	}

	function search_title_highlight() {
	    $title = get_the_title();
	    $keys = implode('|', explode(' ', get_search_query()));
	    $title = preg_replace('/(' . $keys .')/iu', '<strong class="search-highlight"></strong>', $title);

	    echo $title;
	}