$file				= 'video_file';
$config['upload_path']		= './video_folder/';
$config['allowed_types'] 	= 'mov|mpeg|mp3|avi';
$config['max_size']		= '50000';
$config['max_width']  		= '';
$config['max_height']  		= '';
 
$this->upload->initialize($config);
$this->load->library('upload', $config);
 
if(!$this->upload->do_upload($file))
{
	// If there is any error
	$err_msgs .= 'Error in Uploading video '.$this->upload->display_errors().'<br />';
}
else
{
	$data=array('upload_data' => $this->upload->data());
	$video_path = $data['upload_data']['file_name'];
 
	$directory_path 	 = $data['upload_data']['file_path'];
	$directory_path_full      = $data['upload_data']['full_path'];
	$file_name 		= $data['upload_data']['raw_name'];
 
	// ffmpeg command to convert video
 
	exec("ffmpeg -i ".$directory_path_full." ".$directory_path.$file_name.".flv"); 
// $file_name is same file name that is being uploaded but you can give your custom video name after converting So use something like myfile.flv.
 
	/// In the end update video name in DB 
	$array = array(
		'video' => $file_name.'.'.'flv',
		);
	$this->db->set($array);
	$this->db->where('id',$id); // Table where you put video name
	$query = $this->db->update('user_videos'); 	
}

class Encryption {
	var $skey 	= "SuPerEncKey2010"; // you can change it
 
    public  function safe_b64encode($string) {
 
        $data = base64_encode($string);
        $data = str_replace(array('+','/','='),array('-','_',''),$data);
        return $data;
    }
 
	public function safe_b64decode($string) {
        $data = str_replace(array('-','_'),array('+','/'),$string);
        $mod4 = strlen($data) % 4;
        if ($mod4) {
            $data .= substr('====', $mod4);
        }
        return base64_decode($data);
    }
 
    public  function encode($value){ 
 
	    if(!$value){return false;}
        $text = $value;
        $iv_size = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_ECB);
        $iv = mcrypt_create_iv($iv_size, MCRYPT_RAND);
        $crypttext = mcrypt_encrypt(MCRYPT_RIJNDAEL_256, $this->skey, $text, MCRYPT_MODE_ECB, $iv);
        return trim($this->safe_b64encode($crypttext)); 
    }
 
    public function decode($value){
 
        if(!$value){return false;}
        $crypttext = $this->safe_b64decode($value); 
        $iv_size = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_ECB);
        $iv = mcrypt_create_iv($iv_size, MCRYPT_RAND);
        $decrypttext = mcrypt_decrypt(MCRYPT_RIJNDAEL_256, $this->skey, $crypttext, MCRYPT_MODE_ECB, $iv);
        return trim($decrypttext);
    }
}

$this->encrypt->encode('Your data');
$this->encrypt->decode('Your encrypted data');