Почему nginx ставит 500 статус при отдаче файла скриптом?

Пытаюсь отдать видео файл PHP скриптом. Вот исходник:

header("HTTP/1.1 200 OK");
 	//header("Content-Type: video/$ext"); 
	header("Content-Type: application/octet-stream"); 
	header("Content-length: " . filesize($file)); 
	header('Content-Disposition: attachment; filename="' . $output_name . '"'); 

	$fp = fopen($file, 'r');
	while (1)
	{
		$chunk = fread($fp, 1024*1024);
		if (!$chunk) {
			break;
		}
		print $chunk;
	}
	fclose($fp);

то есть напрямую ставлю HTTP/1.1 200 OK. И вот как curl это трейсит

== Info: About to connect() to getfile.qu port 80 (#0)
== Info:   Trying 1.2.3.4...
== Info: Connected to getfile.qu (1.2.3.4) port 80 (#0)
=> Send header, 118 bytes (0x76)
0000: GET /download?id=ae39ea9005c3c9467f0945492771b344 HTTP/1.1
003c: User-Agent: curl/7.29.0
0055: Host: getfile.qu
0067: Accept: */*
0074: 
<= Recv header, 36 bytes (0x24)
0000: HTTP/1.1 500 Internal Server Error
<= Recv header, 15 bytes (0xf)
0000: Server: nginx
<= Recv header, 37 bytes (0x25)
0000: Date: Wed, 24 Jul 2019 08:08:45 GMT
<= Recv header, 40 bytes (0x28)
0000: Content-Type: application/octet-stream
<= Recv header, 24 bytes (0x18)
0000: Content-Length: 383631
<= Recv header, 24 bytes (0x18)
0000: Connection: keep-alive
<= Recv header, 24 bytes (0x18)
0000: Keep-Alive: timeout=60
<= Recv header, 26 bytes (0x1a)
0000: X-Powered-By: PHP/5.4.16
<= Recv header, 56 bytes (0x38)
0000: Content-Disposition: attachment; filename="lalafa.mp4"
<= Recv header, 2 bytes (0x2)
0000: 
<= Recv data, 16100 bytes (0x3ee4)
0000: ....ftypmp42....mp42isomavc1....free............................

то есть статус оказывается 500 после чего файл все равно отдается. Естесственно, браузер его не принимает. Закоментаренный вариант Content-Type не помог. Эта неприятность случалаеться как с mp4 так и с webm, последний не упомянут в конфиге nginx.

Что происзодит и как это пофиксить?

конфиг nginx

# Server globals
user                    nginx;
worker_processes        auto;
worker_rlimit_nofile    65535;
error_log               /var/log/nginx/error.log crit;
pid                     /var/run/nginx.pid;


# Worker config
events {
        worker_connections  1024;
        use                 epoll;
        multi_accept        on;
}


http {
    # Main settings
    sendfile                        on;
    tcp_nopush                      on;
    tcp_nodelay                     on;
    client_header_timeout           1m;
    client_body_timeout             1m;
    client_header_buffer_size       2k;
    client_body_buffer_size         256k;
    client_max_body_size            256m;
    large_client_header_buffers     4   8k;
    send_timeout                    30;
    keepalive_timeout               60 60;
    reset_timedout_connection       on;
    server_tokens                   off;
    server_name_in_redirect         off;
    server_names_hash_max_size      512;
    server_names_hash_bucket_size   512;


    # Log format
    log_format  main    '$remote_addr - $remote_user [$time_local] $request '
                        '"$status" $body_bytes_sent "$http_referer" '
                        '"$http_user_agent" "$http_x_forwarded_for"';
    log_format  bytes   '$body_bytes_sent';
    #access_log          /var/log/nginx/access.log main;
    access_log off;


    # Mime settings
    include             /etc/nginx/mime.types;
    default_type        application/octet-stream;


    # Compression
    gzip                on;
    gzip_comp_level     9;
    gzip_min_length     512;
    gzip_buffers        8 64k;
    gzip_types          text/plain text/css text/javascript text/js text/xml application/json application/javascript application/x-javascript application/xml application/xml+rss application/x-font-ttf image/svg+xml font/opentype;
    gzip_proxied        any;
    gzip_disable        "MSIE [1-6]\.";


    # Proxy settings
    proxy_redirect      off;
    proxy_set_header    Host            $host;
    proxy_set_header    X-Real-IP       $remote_addr;
    proxy_set_header    X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_pass_header   Set-Cookie;
    proxy_connect_timeout   90;
    proxy_send_timeout  90;
    proxy_read_timeout  90;
    proxy_buffers       32 4k;




 

    # Error pages
    error_page          403          /error/403.html;
    error_page          404          /error/404.html;
    error_page          502 503 504  /error/50x.html;


    # Cache settings
    proxy_cache_path /var/cache/nginx levels=2 keys_zone=cache:10m inactive=60m max_size=1024m;
    proxy_cache_key "$host$request_uri $cookie_user";
    proxy_temp_path  /var/cache/nginx/temp;
    proxy_ignore_headers Expires Cache-Control;
    proxy_cache_use_stale error timeout invalid_header http_502;
    proxy_cache_valid any 1d;


    # Cache bypass
    map $http_cookie $no_cache {
        default 0;
        ~SESS 1;
        ~wordpress_logged_in 1;
    }


    # File cache settings
    open_file_cache          max=10000 inactive=30s;
    open_file_cache_valid    60s;
    open_file_cache_min_uses 2;
    open_file_cache_errors   off;


    # Wildcard include
    include             /etc/nginx/conf.d/*.conf;
}


server {
    listen      1.2.3.4:80;
    server_name getfile.qu www.getfile.qu;
    error_log  /var/log/httpd/domains/getfile.qu.error.log error;

    location / {
        proxy_pass      http://1.2.3.4:8080;
        location ~* ^.+\.(jpeg|jpg|png|gif|bmp|ico|svg|tif|tiff|css|js|htm|html|ttf|otf|webp|woff|txt|csv|rtf|doc|docx|xls|xlsx|ppt|pptx|odf|odp|ods|odt|pdf|psd|ai|eot|eps|ps|zip|tar|tgz|gz|rar|bz2|7z|aac|m4a|mp3|mp4|ogg|wav|wma|3gp|avi|flv|m4v|mkv|mov|mpeg|mpg|wmv|exe|iso|dmg|swf)$ {
            root           /home/admin/web/getfile.qu/public_html;
            access_log     /var/log/httpd/domains/getfile.qu.log combined;
            access_log     /var/log/httpd/domains/getfile.qu.bytes bytes;
            expires        max;
            try_files      $uri @fallback;
        }
    }

    location /error/ {
        alias   /home/admin/web/getfile.qu/document_errors/;
    }

    location @fallback {
        proxy_pass      http://1.2.3.4:8080;
    }

    location ~ /\.ht    {return 404;}
    location ~ /\.svn/  {return 404;}
    location ~ /\.git/  {return 404;}
    location ~ /\.hg/   {return 404;}
    location ~ /\.bzr/  {return 404;}

    include /home/admin/conf/web/nginx.getfile.qu.conf*;
}