@Override
  public void onDownloadMetadata(DownloadItem item, Exception error) {
    LOGD("onDownloadMetadata", "");

    DownloadItem.TrackSelector trackSelector = item.getTrackSelector();
    if (trackSelector != null) {
      List<DownloadItem.Track> downloadedVideoTracks =
          trackSelector.getDownloadedTracks(DownloadItem.TrackType.VIDEO);

      List<DownloadItem.Track> availableTracks =
          trackSelector.getAvailableTracks(DownloadItem.TrackType.AUDIO);
      if (availableTracks.size() > 0) {
        trackSelector.setSelectedTracks(DownloadItem.TrackType.AUDIO, availableTracks);
      }
      try {
        trackSelector.apply();
      } catch (IOException e) {
        e.printStackTrace();
      }
    }

    item.startDownload();
  }