¿Obtener .mp4 de redtube?

<?php  
error_reporting(0);  
  
$conexion = curl_init('http://redtube.com/'.$_GET['id']);  
curl_setopt($conexion, CURLOPT_USERAGENT, 'Mozilla/5.0 (Linux; U; Android 4.0.3; ko-kr; LG-L160L Build/IML74K) AppleWebkit/534.30 (KHTML, like Gecko) Version/4.0 Mobile Safari/534.30');  
curl_setopt($conexion, CURLOPT_HTTPHEADER, array('Accept-Language: es-es,en'));  
curl_setopt($conexion, CURLOPT_POSTREDIR, 3);  
curl_setopt($conexion, CURLOPT_FOLLOWLOCATION, true);  
curl_setopt($conexion, CURLOPT_RETURNTRANSFER, TRUE);  
$respuesta = curl_exec($conexion);  
curl_close($conexion);  

if(preg_match('|<source src="(.*?)" type="video/mp4">|sU', $respuesta, $mp4)){  
    echo $mp4[1];  
} 
  
?>