Codeigniter video upload (view+controller)

//VIEW

<?php echo $error;?>
<?php echo form_open_multipart('upload/do_upload');?>
<input type="file" name="userfile" size="20" />
<br /><br />
<input type="submit" value="upload" />



//CONTROLLER

public function do_upload()
        {
                $config['upload_path']          = './videos/';
                $config['allowed_types']        = 'avi|flv|wmv|mpeg|mp3|mp4';
                $config['max_size']             = 100;
                $config['max_width']            = 1024;
                $config['max_height']           = 768;
                $this->load->library('upload', $config);
}