in dmc.py [0:0]
def __init__(self, env, num_frames, pixels_key='pixels'):
self._env = env
self._num_frames = num_frames
self._frames = deque([], maxlen=num_frames)
self._pixels_key = pixels_key
wrapped_obs_spec = env.observation_spec()
assert pixels_key in wrapped_obs_spec
pixels_shape = wrapped_obs_spec[pixels_key].shape
# remove batch dim
if len(pixels_shape) == 4:
pixels_shape = pixels_shape[1:]
self._obs_spec = specs.BoundedArray(shape=np.concatenate(
[[pixels_shape[2] * num_frames], pixels_shape[:2]], axis=0),
dtype=np.uint8,
minimum=0,
maximum=255,
name='observation')