public function getOutput()
    {
        // Persistent opening
        $bufferKey = get_class($this).$this->binary.$this->movieFile;

        if (true === $this->persistent
            && array_key_exists($bufferKey, self::$persistentBuffer)
        ) {
            return self::$persistentBuffer[$bufferKey];
        }

        return $this->output;
    }