ERR_CONTENT_LENGTH_MISMATCH when uploading video to chrome

Question

So, I get this error when part of the video is playing. When Chrome fully downloads the video, it stops playing with this error. Also, the request status changes from 206 to (unsuccessful), and then Chrome sends other requests with Range:bytes=2990775-, and the server response:

Accept-Ranges:bytes
Cache-Control:private
Connection:keep-alive
Content-Disposition:attachment; filename="About The Author.mp4"
Content-Length:0
Content-Range:bytes 2990775-2990775/2990776
Content-Transfer-Encoding:binary
Content-Type:video/mp4
Date:Tue, 14 Feb 2017 13:46:24 GMT
Last-Modified:Wed, 08 Feb 2017 05:43:27 GMT
Pragma:public
Server:Apache/2
Vary:User-Agent
X-Powered-By:PHP/5.4.45

I have another site on the same server, and it works fine there.

Here is my PHP code:

        $filesize = filesize($resource->path);

        $matches = explode("-", substr($_SERVER['HTTP_RANGE'],6));
        if (empty($matches[1]))
        {
            $matches[1] = $filesize - 1;
        }

        $offset = intval($matches[0]);
        $length = intval($matches[1]) - $offset;

        $file = fopen($resource->path, 'r');

        fseek($file, $offset);

        $data = fread($file, $length);
        fclose($file);

        header('HTTP/1.1 206 Partial Content');
        header('Content-Range: bytes ' . $offset . '-' . ($offset + $length) . '/' . $filesize);

        header('Pragma: public');   
        header('Last-Modified: '.gmdate ('D, d M Y H:i:s', filemtime ($resource->path)).' GMT');
        header('Cache-Control: private',false);
        header('Content-Type: ' . $mime);
        header('Content-Length: ' . ($length + 1));
        header('Content-Disposition: attachment; filename="' . $resource->filename . '"');
        header('Content-Transfer-Encoding: binary');
        header('Accept-Ranges: bytes');

        print($data);

Sorry for my bad english.

Answer 1

I found a problem.

I changed $data = fread($file, $length);to $data = fread($file, $length + 1);.

I do not know why the requested length should be plus one, but it solved the problem.