static void get_parameters(BC_WindowBase *parent_window,Asset *asset,
BC_WindowBase *&format_window,int audio_options,int video_options);
static int check_sig(Asset *asset);
static void get_parameters(BC_WindowBase *parent_window,Asset *asset,
BC_WindowBase *&format_window,int audio_options,int video_options);
static int check_sig(Asset *asset);