extern std::string careful_string_filter (std::string);
extern std::pair<int, int> audio_channel_types (std::list<int> mapped, int channels);
extern std::shared_ptr<AudioBuffers> remap (std::shared_ptr<const AudioBuffers> input, int output_channels, AudioMapping map);
-extern Eyes increment_eyes (Eyes e);
extern size_t utf8_strlen (std::string s);
extern std::string day_of_week_to_string (boost::gregorian::greg_weekday d);
extern void emit_subtitle_image (dcpomatic::ContentTimePeriod period, dcp::SubtitleImage sub, dcp::Size size, std::shared_ptr<TextDecoder> decoder);