From - https://stackoverflow.com/a/51246730/5627904

getYouTubeId.php

<?php
/**
 * @param string $url
 * @see https://stackoverflow.com/a/51246730/5627904
 */
function get_youtube_id($url) {
	// Here is a sample of the URLs this regex matches: (there can be more content after the given URL that will be ignored)
	// http://youtu.be/dQw4w9WgXcQ
	// http://www.youtube.com/embed/dQw4w9WgXcQ
	// http://www.youtube.com/watch?v=dQw4w9WgXcQ
	// http://www.youtube.com/?v=dQw4w9WgXcQ
	// http://www.youtube.com/v/dQw4w9WgXcQ
	// http://www.youtube.com/e/dQw4w9WgXcQ
	// http://www.youtube.com/user/username#p/u/11/dQw4w9WgXcQ
	// http://www.youtube.com/sandalsResorts#p/c/54B8C800269D7C1B/0/dQw4w9WgXcQ
	// http://www.youtube.com/watch?feature=player_embedded&v=dQw4w9WgXcQ
	// http://www.youtube.com/?feature=player_embedded&v=dQw4w9WgXcQ
	// It also works on the youtube-nocookie.com URL with the same above options.
	// It will also pull the ID from the URL in an embed code (both iframe and object tags)

	// $url = "https://www.youtube.com/watch?v=v2_MLFVdlQM";

	preg_match('%(?:youtube(?:-nocookie)?\.com/(?:[^/]+/.+/|(?:v|e(?:mbed)?)/|.*[?&]v=)|youtu\.be/)([^"&?/ ]{11})%i', $url, $match);
	$youtube_id = isset($match[1]) ? $match[1] : '';
	return $youtube_id;
};