void add_properties (std::shared_ptr<const Film> film, std::list<UserProperty> &) const;
void modify_position (std::shared_ptr<const Film> film, dcpomatic::DCPTime& pos) const;
void add_properties (std::shared_ptr<const Film> film, std::list<UserProperty> &) const;
void modify_position (std::shared_ptr<const Film> film, dcpomatic::DCPTime& pos) const;