Creates a border around each frame to differentiate input and target.

  Args:
    video: 5-D NumPy array.
    color: string, "blue", "red" or "green".
    border_percent: Percentarge of the frame covered by the border.
  Returns:
    video: 5-D NumPy array.

def create_border(video, color="blue", border_percent=2):
  """Creates a border around each frame to differentiate input and target.

  Args:
    video: 5-D NumPy array.
    color: string, "blue", "red" or "green".
    border_percent: Percentarge of the frame covered by the border.
  Returns:
    video: 5-D NumPy array.
  """
  # Do not create border if the video is not in RGB format
  if video.shape[-1] != 3:
    return video
  color_to_axis = {"blue": 2, "red": 0, "green": 1}
  axis = color_to_axis[color]
  _, _, height, width, _ = video.shape
  border_height = np.ceil(border_percent * height / 100.0).astype(np.int)
  border_width = np.ceil(border_percent * width / 100.0).astype(np.int)
  video[:, :, :border_height, :, axis] = 255
  video[:, :, -border_height:, :, axis] = 255
  video[:, :, :, :border_width, axis] = 255
  video[:, :, :, -border_width:, axis] = 255
  return video