bool Tracks::TrackIsVideo(uint64_t track_number) const {
  const Track* const track = GetTrackByNumber(track_number);

  if (track->type() == kVideo)
    return true;

  return false;
}
bool Tracks::TrackIsVideo(uint64_t track_number) const {
  const Track* const track = GetTrackByNumber(track_number);

  if (track->type() == kVideo)
    return true;

  return false;
}