php serve mp4 instantly (before loading everything) - php

Question

I'm implementing a HTML5 video player that serves mp4-files.
When I use a regular mp4 file as a source, the video starts pretty soon and I can also seek to parts that aren't downloaded yet.
Now, I want to secure my video files, i.e. they are stored below the web root and the video src is a php-file, that checks, if the user is allowed to view the video.
So my HTML looks like this:
...
<video src="http://videoserver.com/stream.php?file=videoxy.mp4">
...
And the stream.php:
...
if ($access_granted) {
if ($fd = fopen($path, "rb")) {
$fsize = filesize($path);
header("Content-Type: video/mp4");
header("Content-Disposition: inline; filename=\"".$filename."\"");
header('Content-Transfer-Encoding: binary');
header("Content-Length: $fsize");
fpassthru($fd);
} else {
die('file not found');
}
} else {
die('forbidden');
}
...
Now, the video will still be played, but only after the video is completely downloaded.
How can I make the video start before everything is downloaded? Also I'd like seeking to not yet downloaded parts to work as before.

Answer 1

I found the solution from this gist to be working:
...
if ($access_granted) {
if ($fp = fopen($path, "rb")) {
$size = filesize($path);
$length = $size;
$start = 0;
$end = $size - 1;
header('Content-type: video/mp4');
header("Accept-Ranges: 0-$length");
if (isset($_SERVER['HTTP_RANGE'])) {
$c_start = $start;
$c_end = $end;
list(, $range) = explode('=', $_SERVER['HTTP_RANGE'], 2);
if (strpos($range, ',') !== false) {
header('HTTP/1.1 416 Requested Range Not Satisfiable');
header("Content-Range: bytes $start-$end/$size");
exit;
}
if ($range == '-') {
$c_start = $size - substr($range, 1);
} else {
$range = explode('-', $range);
$c_start = $range[0];
$c_end = (isset($range[1]) && is_numeric($range[1])) ? $range[1] : $size;
}
$c_end = ($c_end > $end) ? $end : $c_end;
if ($c_start > $c_end || $c_start > $size - 1 || $c_end >= $size) {
header('HTTP/1.1 416 Requested Range Not Satisfiable');
header("Content-Range: bytes $start-$end/$size");
exit;
}
$start = $c_start;
$end = $c_end;
$length = $end - $start + 1;
fseek($fp, $start);
header('HTTP/1.1 206 Partial Content');
}
header("Content-Range: bytes $start-$end/$size");
header("Content-Length: ".$length);
$buffer = 1024 * 8;
while(!feof($fp) && ($p = ftell($fp)) <= $end) {
if ($p + $buffer > $end) {
$buffer = $end - $p + 1;
}
set_time_limit(0);
echo fread($fp, $buffer);
flush();
}
fclose($fp);
exit();
} else {
die('file not found');
}
} else {
die('forbidden');
}
...