extern void check_image (boost::filesystem::path, boost::filesystem::path);
extern boost::filesystem::path test_film_dir (std::string);
extern void write_image (boost::shared_ptr<const Image> image, boost::filesystem::path file, std::string format);
+boost::filesystem::path video_file (boost::shared_ptr<const Film> film);
+void check_one_frame (boost::filesystem::path dcp, int64_t index, boost::filesystem::path ref);