def cvt2frames(self,
                   frame_dir,
                   file_start=0,
                   filename_tmpl='{:06d}.jpg',
                   start=0,
                   max_num=0,
                   show_progress=True):
        """Convert a video to frame images.

        Args:
            frame_dir (str): Output directory to store all the frame images.
            file_start (int): Filenames will start from the specified number.
            filename_tmpl (str): Filename template with the index as the
                placeholder.
            start (int): The starting frame index.
            max_num (int): Maximum number of frames to be written.
            show_progress (bool): Whether to show a progress bar.
        """
        mkdir_or_exist(frame_dir)
        if max_num == 0:
            task_num = self.frame_cnt - start
        else:
            task_num = min(self.frame_cnt - start, max_num)
        if task_num <= 0:
            raise ValueError('start must be less than total frame number')
        if start > 0:
            self._set_real_position(start)

        def write_frame(file_idx):
            img = self.read()
            if img is None:
                return
            filename = osp.join(frame_dir, filename_tmpl.format(file_idx))
            cv2.imwrite(filename, img)

        if show_progress:
            track_progress(write_frame, range(file_start,
                                              file_start + task_num))
        else:
            for i in range(task_num):
                write_frame(file_start + i)
Convert a video to frame images.

        Args:
            frame_dir (str): Output directory to store all the frame images.
            file_start (int): Filenames will start from the specified number.
            filename_tmpl (str): Filename template with the index as the
                placeholder.
            start (int): The starting frame index.
            max_num (int): Maximum number of frames to be written.
            show_progress (bool): Whether to show a progress bar.
        
ControlNet-v1-1-nightly/annotator/uniformer/mmcv/video/io.py