change post type excerpt name and desc

// change video post type excerpt name and desc
function omo_change_excerpt_name( $translated_text, $text, $domain ) {
    if ( $_GET['post_type'] == 'video' ) {
        switch ( $translated_text ) {
            case 'Excerpt' :
                $translated_text = 'Video Description';
                break;
            case 'Excerpts are optional hand-crafted summaries of your content that can be used in your theme. <a href="http://codex.wordpress.org/Excerpt" target="_blank">Learn more about manual excerpts.</a>' :
                $translated_text = 'Put Your Video description Here';
                break;
        }
    }
    return $translated_text;
}
add_filter( 'gettext', 'omo_change_excerpt_name', 20, 3 );