Custom Meta Box Skeleton Code.

meta-box-post_type.php

<?php
// Just replace pronamic with an unique identifier.
// and replace video with a slugname for your function of the box.
add_action( 'add_meta_boxes', 'wp_pronamic_add_meta_boxes' );
add_action( 'save_post', 'wp_pronamic_video_meta_box_save', 10, 2 );
function wp_pronamic_add_meta_boxes() {
	add_meta_box( 'pronamic_video_meta_box', __( 'Review Rating', 'wp_vision' ), 'wp_pronamic_video_meta_box_show', 'pronamic', 'normal' );
}

function wp_pronamic_video_meta_box_show( WP_Post $post ) {
	$nonce      = wp_nonce_field( 'wp_pronamic_video_meta_box_nonce', 'wp_pronamic_video_meta_box', true, false );
	
	include 'views/wp_pronamic_video_meta_box_show.php';
}

function wp_pronamic_video_meta_box_save( $post_id, WP_Post $post ) {
	if ( defined( 'DOING_AUTOSAVE' ) && DOING_AUTOSAVE )
		return;
	
	if ( ! filter_has_var( INPUT_POST, 'wp_pronamic_video_meta_box' ) )
		return;
	
	if ( ! wp_verify_nonce( $_POST['wp_pronamic_video_meta_box'], 'wp_pronamic_video_meta_box_nonce' ) )
		return;
	
}