extern std::string get_optional_string (std::multimap<std::string, std::string> const & kv, std::string k);
extern void* wrapped_av_malloc (size_t);
extern int64_t divide_with_round (int64_t a, int64_t b);
extern std::string get_optional_string (std::multimap<std::string, std::string> const & kv, std::string k);
extern void* wrapped_av_malloc (size_t);
extern int64_t divide_with_round (int64_t a, int64_t b);