Modified version of 'https://github.com/eosgood/fbphpsdk/blob/master/async/photo.php' to support video uploads. Tested with 177 MB MKV video.

gistfile1.txt

<?php

// Provides access to app specific values such as your app id and app secret.
// Defined in 'AppInfo.php'
require_once('../utils/AppInfo.php');

require_once('../facebook-php-sdk/src/facebook.php');

$facebook = new Facebook(array(
  'appId'  => AppInfo::appID(),
  'secret' => AppInfo::appSecret(),
));

$facebook->setFileUploadSupport(true);

if (isset($_POST['graph'])) {
        $user = $facebook->getUser();

        $data = array();
        $img = '../vid/example.mkv';

        $post_data = array(
                'videoData' => '@' . $img,
                'title' => 'Test Video Upload',
                'description' => 'Video uploaded with the php sdk',
        );

        try {
        $data = $facebook->api(
                '/me/videos', 'POST',
                $post_data
        );
    } catch(FacebookApiException $e) {
        $data = array('error' => $e->getMessage());
    }

    echo json_encode($data);
}