typedef std::map<std::weak_ptr<Piece>, std::shared_ptr<PlayerVideo>, std::owner_less<std::weak_ptr<Piece>>> LastVideoMap;
LastVideoMap _last_video;
typedef std::map<std::weak_ptr<Piece>, std::shared_ptr<PlayerVideo>, std::owner_less<std::weak_ptr<Piece>>> LastVideoMap;
LastVideoMap _last_video;