Gets the video ID out of the full youtube url or out of the "share" url.

get-youtube-id.php

// Extracts the video ID from a youtube URL
function get_youtube_id($url){
	// share URL
	if( strstr($url, 'youtu.be/') ){
		$id = str_replace('http://youtu.be/', '', $url);
	}else{ 
		// full youtube URL
		$query_string = array();
		parse_str(parse_url($url, PHP_URL_QUERY), $query_string);
		$id = $query_string["v"];
	}
	return $id;
}