public static extern int ass_step_sub(ref ASS_Track track, int now, int movement);
public static extern void ass_flush_events(ref ASS_Track track);
public static extern int ass_read_styles(ref ASS_Track track, IntPtr fname, IntPtr codepage);
public static extern void ass_process_chunk(ref ASS_Track track, IntPtr data, int size, int timecode, int duration);
public static extern void ass_set_check_readorder(ref ASS_Track track, int check_readorder);
public static extern void ass_process_codec_private(ref ASS_Track track, IntPtr data, int size);
public static extern void ass_process_data(ref ASS_Track track, IntPtr data, int size);
public static extern void ass_free_event(ref ASS_Track track, int eid);
public static extern void ass_free_style(ref ASS_Track track, int sid);
public static extern void ass_process_force_style(ref ASS_Track track);