print "X-Sendfile: C:\\Path\\to\\file\\video\\";
print "Content-Type:application/octet-stream; name=\"File-12.mp4\"\r\n";
print "Content-Disposition: attachment; filename=\"File-12.mp4\"\r\n\n";
print "\n\n";
exit;

##</code><code>##

<?php
...
if ($user->isLoggedIn())
{
    header("X-Sendfile: $path_to_somefile");
    header("Content-Type: application/octet-stream");
    header("Content-Disposition: attachment; filename=\"$somefile\"");
    exit;
}
?>
<h1>Permission denied</h1>
<p>Login first!</p>

##</code><code>##

# enable xsendfile
XSendFile On
XSendFilePath C:/Path/To/Files/

##</code><code>##

my $file = "C:/Patch to file/FiletoSend.mp4";
my $filesize = -s $file;
print "Content-Type:video/mp4\n";
# remove comment below to make file download. Add the comment to stream data to player
#print "Content-Disposition: attachment; filename=\"FiletoSend.mp4\"\n";
print "Content-Length: $filesize\n";
print "X-Sendfile: $file";
print "\n\n";

exit;