extern void setup_audio_channels_choice (wxChoice* choice, int minimum);
extern wxSplashScreen* maybe_show_splash ();
extern boost::filesystem::path path_from_file_dialog (wxFileDialog* dialog, std::string extension);
+extern double calculate_mark_interval (double start);
extern void checked_set (FilePickerCtrl* widget, boost::filesystem::path value);
extern void checked_set (wxSpinCtrl* widget, int value);