PHP：获取重定向到mp4的URL

Hello I have an URL that redirects to another URL which then redirects to an .mp4. I want to get the link of the .mp4 as plain text.

An example for the workflow:

http://myhost.com/show/media/xyz

redirects to:

 http://myhost2:81/media/xyz

redirects to:

http://myhost3:443/media/xyz.mp4

I tried with the following code below:

function get_redirect_target($destination){
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $destination);
curl_setopt($ch, CURLOPT_HEADER, true);
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, false);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, TRUE);
curl_setopt($ch, CURLOPT_NOBODY, true);
$a = curl_exec($ch);
if(preg_match('#Location: (.*)#', $a, $r))
return  $l = trim($r[1]);
}

With the code below it works to get the redirect url until "http://myhost2:81/media/xyz" but for the last redirects url it doesn't work ("connection timed out"). I think the script tries to load the whole .mp4 file, how can I avoid this and how can I only get the link of the .mp4?

Btw: The workflow works perfect with the function "get_headers()" in xampp locally but on the server I always receive "connection timed out".

Thanks already in advance