Differnt Site Title and Tagline per Page WordPress Theme

/*
* customize different Site Title
* and Tagline per (static) page
*/

// create meta boxe for 'Custom Site Title' field below page editor

add_action( 'admin_menu', 'custom_site_title' );
add_action( 'save_post', 'save_custom_site_title' );

function custom_site_title() {
    add_meta_box( 'custom_site_title', 'Custom Site Title for this page <small>(if left empty, the general Site Title will be used)</small>', 'custom_site_title_input_function', 'page', 'normal', 'high' );
}

function custom_site_title_input_function() {
    global $post;
    echo '<input type="hidden" name="custom_site_title_input_hidden" id="custom_site_title_input_hidden" value="'.wp_create_nonce( 'custom_site_title-nonce' ).'" />';
    echo '<input type="text" name="custom_site_title_input" id="custom_site_title_input" style="width:100%;" value="'.get_post_meta( $post->ID, '_custom_site_title', true ).'" />';
}

function save_custom_site_title( $post_id ) {
    if (isset( $_POST['custom_site_title_input_hidden'] )) if (!wp_verify_nonce($_POST['custom_site_title_input_hidden'], 'custom_site_title-nonce')) return $post_id;
    if (defined('DOING_AUTOSAVE') && DOING_AUTOSAVE) return $post_id;
    if (isset( $_POST['custom_site_title'] )) {
        $customSiteTitle = $_POST['custom_site_title_input'];
        update_post_meta( $post_id, '_custom_site_title', $customSiteTitle );
    }
}

// create meta boxe for 'Custom Tagline' field below page editor

add_action( 'admin_menu', 'custom_site_tagline' );
add_action( 'save_post', 'save_custom_site_tagline' );

function custom_site_tagline() {
    add_meta_box( 'custom_site_tagline', 'Custom Tagline for this page <small>(if left empty, the general Tagline will be used)</small>', 'custom_site_tagline_input_function', 'page', 'normal', 'high' );
}

function custom_site_tagline_input_function() {
    global $post;
    echo '<input type="hidden" name="custom_site_tagline_input_hidden" id="custom_site_tagline_input_hidden" value="'.wp_create_nonce( 'custom_site_tagline-nonce' ).'" />';
    echo '<input type="text" name="custom_site_tagline_input" id="custom_site_tagline_input" style="width:100%;" value="'.get_post_meta( $post->ID, '_custom_site_tagline', true ).'" />';
}

function save_custom_site_tagline( $post_id ) {
    if (isset( $_POST['custom_site_tagline_input_hidden'] )) if (!wp_verify_nonce($_POST['custom_site_tagline_input_hidden'], 'custom_site_tagline-nonce')) return $post_id;
    if (defined('DOING_AUTOSAVE') && DOING_AUTOSAVE) return $post_id;
    if (isset( $_POST['custom_site_tagline'] )) {
        $customSiteTagline = $_POST['custom_site_tagline_input'];
        update_post_meta( $post_id, '_custom_site_tagline', $customSiteTagline );
    }
}

//preparing the output

add_filter( 'bloginfo', 'custom_site_title_tagline_output', 2, 10 );

function custom_site_title_tagline_output( $site_bloginfo, $show ) {
    global $post;
    if( $show == 'name' && is_page() && get_post_meta( $post->ID, '_custom_site_title', true ) ) {
        $site_bloginfo = get_post_meta( $post->ID, '_custom_site_title', true );
    }
    if( $show == 'description' && is_page() && get_post_meta( $post->ID, '_custom_site_tagline', true ) ) {
        $site_bloginfo = get_post_meta( $post->ID, '_custom_site_tagline', true );
    }
    return $site_bloginfo;
}