protected function mergeOptions($src, $dst, &$options) {
    if (!isset($options['width']) && !isset($options['height'])) {
      $info = $this->getVideoInfo($src);
      $options['width'] = $info['width'];
      $options['height'] = $info['height'];
      if (!$info['audioStreams']) {
        $options['audio'] = false;
      }
    }
    if (!isset($options['targetFormat'])) {
      $ext = strtolower(substr($dst, strrpos($dst, '.') + 1));
      $options['targetFormat'] = $ext;
    }
  }