video size is 0 bytes on upload

when i upload my app using php api version 2 it upload the file but the size of file is 0 bytes

below is mine code ..... can someone guide me 

$headers = array('Authorization: Bearer '. $token,
'Content-Type: application/octet-stream',
'Dropbox-API-Arg: '.
json_encode(
array(
"path"=> '/'. date("l-m-y") .'/'. basename($files1),
"mode" => "add",
"autorename" => true,
"mute" => false
)
)

);

$ch = curl_init($api_url);

curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
curl_setopt($ch, CURLOPT_POST, true);

$path = $files1;
$fp = fopen($path, 'rb');
$filesize = filesize($path);

curl_setopt($ch, CURLOPT_POSTFIELDS, fread($fp, $filesize));
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
// curl_setopt($ch, CURLOPT_VERBOSE, 1); // debug

$response = curl_exec($ch);
$http_code = curl_getinfo($ch, CURLINFO_HTTP_CODE);

if($http_code==200){
curl_close($ch);