def _capture_metadata(n_frames, dropped_frames=None):
    """
    Returns a dictionary as it is usually saved by the seven
    camera setup in the "capture_metadata.json" file.
    It assumes that no frames where dropped.

    Parameters
    ----------
    n_frames : list of integers
        Number of frames for each camera.
    dropped_frames : list of list of integers
        Frames that were dropped for each camera.
        Default is None which means no frames where
        dropped.

    Returns
    -------
    capture_info : dict
        Default metadata dictionary for the seven camera
        system.
    """
    if dropped_frames is None:
        dropped_frames = [[] for i in range(len(n_frames))]
    capture_info = {"Frame Counts": {}}
    for cam_idx, n in enumerate(n_frames):
        frames_dict = {}
        current_frame = 0
        for i in range(n):
            while current_frame in dropped_frames[cam_idx]:
                current_frame += 1
            frames_dict[str(i)] = current_frame
            current_frame += 1
        capture_info["Frame Counts"][str(cam_idx)] = frames_dict
    return capture_info