Forcer le téléchargement d'une vidéo en mp4

<?php 
$file = 'toystory3.mp4'; 

if (file_exists($file)) { 
    header('Content-Description: File Transfer'); 
    header('Content-Type: application/octet-stream'); 
    header('Content-Disposition: attachment; filename="'.basename($file).'"'); 
    header('Content-Transfer-Encoding: binary'); 
    header('Expires: 0'); 
    header('Cache-Control: must-revalidate, post-check=0, pre-check=0'); 
    header('Pragma: public'); 
    header('Content-Length: ' . filesize($file)); 
    ob_clean(); 
    flush(); 
    readfile($file); 
    exit; 
} 
?>

<a href="video/film/telechargement_toystory3.php?file=video/film/toystory3.mp4" >- Toy Story 3</a>