Parses a URL and returns the correct video ID based on service.

get-video-id.php

/**
 * Parses a URL and returns the correct video ID based on service.
 * 
 * @param  string $url     the URL to parse
 * @param  string $service 'youtube', 'vimeo' etc.
 * 
 * @return string
 */
function get_video_id($url, $service = 'youtube') {
	$match = '';

	switch ($service) {
		case 'youtube':
			$regex = "#(?<=v=)[a-zA-Z0-9-]+(?=&)|(?<=v\/)[^&\n]+|(?<=v=)[^&\n]+|(?<=youtu.be/)[^&\n]+#";
    		if (preg_match($regex, $url, $match)) {
    			$match = $match[0];
    		}
			break;
		case 'vimeo':
			$regex = "/vimeo\.com\/([^&]*)/i";
			if (preg_match($regex, $url, $match)) {
    			$match = $match[1];
    		}
    		break;
    	case 'facebook':
			parse_str(parse_url($url , PHP_URL_QUERY), $v);
			$match = @$v['v'];
    		break;
		default:
			$match = 'get_video_id() > SERVICE NOT SUPPORTED!';
			break;
	}

	return $match;
}