This library lets you extract a video URL from a webpage by providing a wrapper for youtube-dl.
It is primarily used by AllTube Download.
You can install it with:
composer require rudloff/alltube-library
You can then use it in your PHP code:
use Alltube\Library\Downloader;
require_once __DIR__.'/vendor/autoload.php';
$downloader = new Downloader('/usr/local/bin/youtube-dl');
$video = $downloader->getVideo('https://www.youtube.com/watch?v=dQw4w9WgXcQ');
$video->getUrl();
You can also have a look at this example project.