public function CalculateCompressionRatioAudio() {
    if (empty($this->info['audio']['bitrate']) || empty($this->info['audio']['channels']) || empty($this->info['audio']['sample_rate']) || !is_numeric($this->info['audio']['sample_rate'])) {
      return false;
    }
    $this->info['audio']['compression_ratio'] = $this->info['audio']['bitrate'] / ($this->info['audio']['channels'] * $this->info['audio']['sample_rate'] * (!empty($this->info['audio']['bits_per_sample']) ? $this->info['audio']['bits_per_sample'] : 16));

    if (!empty($this->info['audio']['streams'])) {
      foreach ($this->info['audio']['streams'] as $streamnumber => $streamdata) {
        if (!empty($streamdata['bitrate']) && !empty($streamdata['channels']) && !empty($streamdata['sample_rate'])) {
          $this->info['audio']['streams'][$streamnumber]['compression_ratio'] = $streamdata['bitrate'] / ($streamdata['channels'] * $streamdata['sample_rate'] * (!empty($streamdata['bits_per_sample']) ? $streamdata['bits_per_sample'] : 16));
        }
      }
    }
    return true;
  }