chore(format): formatting code

Observations were sent as base64-in-JSON, which inflates every camera
frame 33% purely to fit binary JPEG inside a text protocol (~11 Mbps at
3 cameras x 30 Hz). Send a ZMQ multipart message instead: a JSON header
frame (state + camera order) followed by one raw JPEG frame per camera.

Benchmarked on hardware: -25% wire size (invariant across contention),
lower and tighter latency, and no dropped frames under load where the
base64 format stalled.

ZMQ_CONFLATE does not support multipart, so the observation sockets use
2-deep high-water marks; the client's existing drain-to-latest loop
preserves the keep-newest behavior.

Breaking wire change: host and client must run the same version.

Co-authored-by: Xingdong Zuo <18168681+zuoxingdong@users.noreply.github.com>
Co-authored-by: Steven Palma <imstevenpmwork@ieee.org>

docs/source/cameras.mdx

@@ -164,8 +164,8 @@ includes the range reported by the sensor. Requesting an unsupported control als
 Omitted controls leave the sensor's existing automatic or manual setting unchanged. These options
 require `use_rgb=True`.
 
-On the RealSense D405, the color stream is provided by the Stereo Module, so changing manual
+Manual color controls require a dedicated RGB module. Cameras without one, such as the RealSense
-exposure or gain also affects the depth stream.
+D405, do not support them and raise an error at connection time.
 
 </hfoption>
 </hfoptions>

docs/source/hil_data_collection.mdx

@@ -59,6 +59,7 @@ The `lerobot-rollout --strategy.type=dagger` mode requires **teleoperators with
 
 - `bi_openarm_mini` - Bimanual OpenArm Mini
 - `so_leader` - SO100 / SO101 leader arm
+- `bi_so_leader` - Bimanual SO100 / SO101 leader arms
 
 > [!IMPORTANT]
 > The provided commands default to `bi_openarm_follower` + `bi_openarm_mini`.

docs/source/robocasa.mdx

@@ -82,6 +82,8 @@ By default the env samples objects only from the `lightwheel` registry (what `--
 
 All eval snippets below mirror the CI command (see `.github/workflows/benchmark_tests.yml`). The `--rename_map` argument maps RoboCasa's native camera keys (`robot0_agentview_left` / `robot0_eye_in_hand` / `robot0_agentview_right`) onto the three-camera (`camera1` / `camera2` / `camera3`) input layout the released `smolvla_robocasa` policy was trained on.
 
+By default, each task uses the rollout horizon registered by RoboCasa. Set `--env.episode_length=<steps>` to apply the same explicit horizon to every selected task.
+
 ### Single-task evaluation (recommended for quick iteration)
 
 ```bash

docs/source/so101.mdx

@@ -338,7 +338,7 @@ It is advisable to install one 3-pin cable in the motor after placing them befor
 <hfoption id="Leader">
 
 - Mount the leader holder onto the wrist and secure it with 4 M3x6mm screws.
-- Attach the handle to motor 5 using 1 M2x6mm screw.
+- Attach the handle to the leader holder using 1 M2x6mm screw.
 - Insert the gripper motor, secure it with 2 M2x6mm screws on each side, attach a motor horn using a M3x6mm horn screw.
 - Attach the follower trigger with 4 M3x6mm screws.
 

examples/isaac_teleop_to_so101/common.py

@@ -44,6 +44,7 @@ from typing import Protocol
 
 import numpy as np
 
+from lerobot.lerobot_types import RobotAction, RobotObservation
 from lerobot.model.kinematics import RobotKinematics
 from lerobot.processor import (
     RobotProcessorPipeline,
@@ -56,7 +57,6 @@ from lerobot.robots.so_follower.robot_kinematic_processor import (
     EEBoundsAndSafety,
     InverseKinematicsEEToJoints,
 )
-from lerobot.types import RobotAction, RobotObservation
 from lerobot.utils.constants import HF_LEROBOT_CALIBRATION, HF_LEROBOT_HOME, TELEOPERATORS
 from lerobot.utils.robot_utils import precise_sleep
 

examples/isaac_teleop_to_so101/isaac_teleop/teleop_so101_leader_arm.py

@@ -38,7 +38,7 @@ from typing import TYPE_CHECKING
 
 import numpy as np
 
-from lerobot.types import RobotAction
+from lerobot.lerobot_types import RobotAction
 
 from .base import _GRIPPER_MOTOR_SCALE, IsaacTeleopTeleoperator, _isaacteleop_available
 from .config_isaac_teleop import SO101LeaderArmConfig

examples/isaac_teleop_to_so101/isaac_teleop/teleop_xr_controller.py

@@ -32,7 +32,7 @@ from typing import TYPE_CHECKING, Any
 
 import numpy as np
 
-from lerobot.types import RobotAction
+from lerobot.lerobot_types import RobotAction
 
 from .base import IsaacTeleopTeleoperator, _isaacteleop_available
 from .config_isaac_teleop import XRControllerConfig

examples/isaac_teleop_to_so101/isaac_teleop/xr_controller_processor.py

@@ -26,8 +26,8 @@ from __future__ import annotations
 from dataclasses import dataclass
 
 from lerobot.configs.types import FeatureType, PipelineFeatureType, PolicyFeature
+from lerobot.lerobot_types import RobotAction
 from lerobot.processor import ProcessorStepRegistry, RobotActionProcessorStep
-from lerobot.types import RobotAction
 from lerobot.utils.rotation import Rotation
 
 from .base import _GRIPPER_MOTOR_SCALE

examples/phone_to_so100/evaluate.py

@@ -21,6 +21,7 @@ from lerobot.cameras.opencv import OpenCVCameraConfig
 from lerobot.common.control_utils import predict_action
 from lerobot.configs import FeatureType, PolicyFeature
 from lerobot.datasets import LeRobotDataset, aggregate_pipeline_dataset_features, create_initial_features
+from lerobot.lerobot_types import RobotAction, RobotObservation
 from lerobot.model.kinematics import RobotKinematics
 from lerobot.policies import make_pre_post_processors
 from lerobot.policies.act import ACTPolicy
@@ -38,7 +39,6 @@ from lerobot.robots.so_follower.robot_kinematic_processor import (
     ForwardKinematicsJointsToEE,
     InverseKinematicsEEToJoints,
 )
-from lerobot.types import RobotAction, RobotObservation
 from lerobot.utils.constants import ACTION, OBS_STR
 from lerobot.utils.feature_utils import build_dataset_frame, combine_feature_dicts
 from lerobot.utils.keyboard_input import init_keyboard_listener

examples/phone_to_so100/record.py

@@ -16,6 +16,7 @@
 
 from lerobot.cameras.opencv import OpenCVCameraConfig
 from lerobot.datasets import LeRobotDataset, aggregate_pipeline_dataset_features, create_initial_features
+from lerobot.lerobot_types import RobotAction, RobotObservation
 from lerobot.model.kinematics import RobotKinematics
 from lerobot.processor import (
     RobotProcessorPipeline,
@@ -36,7 +37,6 @@ from lerobot.scripts.lerobot_record import record_loop
 from lerobot.teleoperators.phone import Phone, PhoneConfig
 from lerobot.teleoperators.phone.config_phone import PhoneOS
 from lerobot.teleoperators.phone.phone_processor import MapPhoneActionToRobotAction
-from lerobot.types import RobotAction, RobotObservation
 from lerobot.utils.feature_utils import combine_feature_dicts
 from lerobot.utils.keyboard_input import init_keyboard_listener
 from lerobot.utils.utils import log_say

examples/phone_to_so100/replay.py

@@ -17,6 +17,7 @@
 import time
 
 from lerobot.datasets import LeRobotDataset
+from lerobot.lerobot_types import RobotAction, RobotObservation
 from lerobot.model.kinematics import RobotKinematics
 from lerobot.processor import (
     RobotProcessorPipeline,
@@ -27,7 +28,6 @@ from lerobot.robots.so_follower import SO100Follower, SO100FollowerConfig
 from lerobot.robots.so_follower.robot_kinematic_processor import (
     InverseKinematicsEEToJoints,
 )
-from lerobot.types import RobotAction, RobotObservation
 from lerobot.utils.constants import ACTION
 from lerobot.utils.robot_utils import precise_sleep
 from lerobot.utils.utils import log_say

examples/phone_to_so100/rollout.py

@@ -27,6 +27,7 @@ Highlight, or DAgger via ``lerobot-rollout --strategy.type=...``.
 
 from lerobot.cameras.opencv import OpenCVCameraConfig
 from lerobot.configs import PreTrainedConfig
+from lerobot.lerobot_types import RobotAction, RobotObservation
 from lerobot.model.kinematics import RobotKinematics
 from lerobot.processor import (
     RobotProcessorPipeline,
@@ -43,7 +44,6 @@ from lerobot.robots.so_follower.robot_kinematic_processor import (
 from lerobot.rollout import BaseStrategyConfig, RolloutConfig, build_rollout_context
 from lerobot.rollout.inference import SyncInferenceConfig
 from lerobot.rollout.strategies import BaseStrategy
-from lerobot.types import RobotAction, RobotObservation
 from lerobot.utils.process import ProcessSignalHandler
 from lerobot.utils.utils import init_logging
 

examples/phone_to_so100/teleoperate.py

@@ -15,6 +15,7 @@
 
 import time
 
+from lerobot.lerobot_types import RobotAction, RobotObservation
 from lerobot.model.kinematics import RobotKinematics
 from lerobot.processor import (
     RobotProcessorPipeline,
@@ -31,7 +32,6 @@ from lerobot.robots.so_follower.robot_kinematic_processor import (
 from lerobot.teleoperators.phone import Phone, PhoneConfig
 from lerobot.teleoperators.phone.config_phone import PhoneOS
 from lerobot.teleoperators.phone.phone_processor import MapPhoneActionToRobotAction
-from lerobot.types import RobotAction, RobotObservation
 from lerobot.utils.robot_utils import precise_sleep
 from lerobot.utils.visualization_utils import init_rerun, log_rerun_data
 

examples/so100_to_so100_EE/evaluate.py

@@ -21,6 +21,7 @@ from lerobot.cameras.opencv import OpenCVCameraConfig
 from lerobot.common.control_utils import predict_action
 from lerobot.configs import FeatureType, PolicyFeature
 from lerobot.datasets import LeRobotDataset, aggregate_pipeline_dataset_features, create_initial_features
+from lerobot.lerobot_types import RobotAction, RobotObservation
 from lerobot.model.kinematics import RobotKinematics
 from lerobot.policies import make_pre_post_processors
 from lerobot.policies.act import ACTPolicy
@@ -38,7 +39,6 @@ from lerobot.robots.so_follower.robot_kinematic_processor import (
     ForwardKinematicsJointsToEE,
     InverseKinematicsEEToJoints,
 )
-from lerobot.types import RobotAction, RobotObservation
 from lerobot.utils.constants import ACTION, OBS_STR
 from lerobot.utils.feature_utils import build_dataset_frame, combine_feature_dicts
 from lerobot.utils.keyboard_input import init_keyboard_listener

examples/so100_to_so100_EE/record.py

@@ -17,6 +17,7 @@
 
 from lerobot.cameras.opencv import OpenCVCameraConfig
 from lerobot.datasets import LeRobotDataset, aggregate_pipeline_dataset_features, create_initial_features
+from lerobot.lerobot_types import RobotAction, RobotObservation
 from lerobot.model.kinematics import RobotKinematics
 from lerobot.processor import (
     RobotProcessorPipeline,
@@ -33,7 +34,6 @@ from lerobot.robots.so_follower.robot_kinematic_processor import (
 )
 from lerobot.scripts.lerobot_record import record_loop
 from lerobot.teleoperators.so_leader import SO100Leader, SO100LeaderConfig
-from lerobot.types import RobotAction, RobotObservation
 from lerobot.utils.feature_utils import combine_feature_dicts
 from lerobot.utils.keyboard_input import init_keyboard_listener
 from lerobot.utils.utils import log_say

examples/so100_to_so100_EE/replay.py

@@ -18,6 +18,7 @@
 import time
 
 from lerobot.datasets import LeRobotDataset
+from lerobot.lerobot_types import RobotAction, RobotObservation
 from lerobot.model.kinematics import RobotKinematics
 from lerobot.processor import (
     RobotProcessorPipeline,
@@ -28,7 +29,6 @@ from lerobot.robots.so_follower import SO100Follower, SO100FollowerConfig
 from lerobot.robots.so_follower.robot_kinematic_processor import (
     InverseKinematicsEEToJoints,
 )
-from lerobot.types import RobotAction, RobotObservation
 from lerobot.utils.constants import ACTION
 from lerobot.utils.robot_utils import precise_sleep
 from lerobot.utils.utils import log_say

examples/so100_to_so100_EE/rollout.py

@@ -25,6 +25,7 @@ forward/inverse kinematics.
 
 from lerobot.cameras.opencv import OpenCVCameraConfig
 from lerobot.configs import PreTrainedConfig
+from lerobot.lerobot_types import RobotAction, RobotObservation
 from lerobot.model.kinematics import RobotKinematics
 from lerobot.processor import (
     RobotProcessorPipeline,
@@ -41,7 +42,6 @@ from lerobot.robots.so_follower.robot_kinematic_processor import (
 from lerobot.rollout import BaseStrategyConfig, RolloutConfig, build_rollout_context
 from lerobot.rollout.inference import SyncInferenceConfig
 from lerobot.rollout.strategies import BaseStrategy
-from lerobot.types import RobotAction, RobotObservation
 from lerobot.utils.process import ProcessSignalHandler
 from lerobot.utils.utils import init_logging
 

examples/so100_to_so100_EE/teleoperate.py

@@ -16,6 +16,7 @@
 
 import time
 
+from lerobot.lerobot_types import RobotAction, RobotObservation
 from lerobot.model.kinematics import RobotKinematics
 from lerobot.processor import (
     RobotProcessorPipeline,
@@ -30,7 +31,6 @@ from lerobot.robots.so_follower.robot_kinematic_processor import (
     InverseKinematicsEEToJoints,
 )
 from lerobot.teleoperators.so_leader import SO100Leader, SO100LeaderConfig
-from lerobot.types import RobotAction, RobotObservation
 from lerobot.utils.robot_utils import precise_sleep
 from lerobot.utils.visualization_utils import init_rerun, log_rerun_data
 

pyproject.toml

@@ -67,7 +67,7 @@ dependencies = [
     "einops>=0.8.0,<0.9.0",
 
     # Config & Hub
-    "draccus==0.10.0", # TODO: Relax version constraint
+    "draccus>=0.11.6,<0.12.0",
     "huggingface-hub>=1.0.0,<2.0.0",
     "requests>=2.32.0,<3.0.0",
 

src/lerobot/async_inference/policy_server.py

@@ -38,6 +38,7 @@ import draccus
 import grpc
 import torch
 
+from lerobot.lerobot_types import PolicyAction
 from lerobot.policies import get_policy_class, make_pre_post_processors
 from lerobot.processor import PolicyProcessorPipeline
 from lerobot.transport import (
@@ -45,7 +46,6 @@ from lerobot.transport import (
     services_pb2_grpc,  # type: ignore
 )
 from lerobot.transport.utils import receive_bytes_in_chunks
-from lerobot.types import PolicyAction
 
 from .configs import PolicyServerConfig
 from .constants import SUPPORTED_POLICIES

src/lerobot/cameras/realsense/camera_realsense.py

@@ -365,11 +365,12 @@ class RealSenseCamera(Camera):
         return self._async_read(timeout_ms=10000, read_depth=read_depth)
 
     def _get_color_sensor(self) -> "rs.sensor":
-        """Returns the sensor that controls the color stream.
+        """Returns the dedicated "RGB Camera" sensor that controls the color stream.
 
-        Most RealSense cameras expose "RGB Camera" for color. The D405 has no
+        Manual color controls are only applied to a dedicated RGB module. Cameras
-        separate RGB module — its color stream comes from "Stereo Module".
+        without one (e.g. the D405, whose color stream comes from the shared
-        We try RGB Camera first, then fall back to Stereo Module.
+        "Stereo Module") are unsupported, so we never fall back to another sensor
+        to avoid altering the depth stream.
         """
         if self.rs_profile is None:
             raise RuntimeError(f"{self}: rs_profile must be initialized before use.")
@@ -377,12 +378,14 @@ class RealSenseCamera(Camera):
         device = self.rs_profile.get_device()
         sensors = {s.get_info(rs.camera_info.name): s for s in device.query_sensors()}
 
-        for name in ("RGB Camera", "Stereo Module"):
+        if "RGB Camera" in sensors:
-            if name in sensors:
+            return sensors["RGB Camera"]
-                return sensors[name]
 
         available = list(sensors.keys())
-        raise RuntimeError(f"{self}: no color sensor found. Available sensors: {available}")
+        raise RuntimeError(
+            f"{self}: manual color controls require a dedicated 'RGB Camera' module, which this camera does not have. ",
+            f"Available sensors: {available}.",
+        )
 
     def _set_sensor_option(self, sensor: "rs.sensor", option: "rs.option", value: float, label: str) -> None:
         """Sets a sensor option, re-raising range errors with actionable diagnostics."""

src/lerobot/common/control_utils.py

@@ -35,9 +35,9 @@ else:
 
 if TYPE_CHECKING:
     from lerobot.datasets import LeRobotDataset
+from lerobot.lerobot_types import PolicyAction
 from lerobot.processor import PolicyProcessorPipeline
 from lerobot.robots import Robot
-from lerobot.types import PolicyAction
 
 
 def predict_action(

src/lerobot/configs/policies.py

@@ -163,8 +163,10 @@ class PreTrainedConfig(draccus.ChoiceRegistry, HubMixin, abc.ABC):  # type: igno
         return None
 
     def _save_pretrained(self, save_directory: Path) -> None:
-        with open(save_directory / CONFIG_NAME, "w") as f, draccus.config_type("json"):
+        # Encode against the base class so draccus includes the choice "type" key,
-            draccus.dump(self, f, indent=4)
+        # which `from_pretrained` needs to resolve the concrete subclass.
+        with open(save_directory / CONFIG_NAME, "w") as f:
+            json.dump(draccus.encode(self, PreTrainedConfig), f, indent=4)
 
     @classmethod
     def from_pretrained(

src/lerobot/configs/rewards.py

@@ -103,8 +103,10 @@ class RewardModelConfig(draccus.ChoiceRegistry, HubMixin, abc.ABC):
         pass
 
     def _save_pretrained(self, save_directory: Path) -> None:
-        with open(save_directory / CONFIG_NAME, "w") as f, draccus.config_type("json"):
+        # Encode against the base class so draccus includes the choice "type" key,
-            draccus.dump(self, f, indent=4)
+        # which `from_pretrained` needs to resolve the concrete subclass.
+        with open(save_directory / CONFIG_NAME, "w") as f:
+            json.dump(draccus.encode(self, RewardModelConfig), f, indent=4)
 
     @classmethod
     def from_pretrained(

src/lerobot/configs/train.py

@@ -194,7 +194,11 @@ class TrainPipelineConfig(HubMixin):
             )
 
         if Path(config_path).resolve().exists():
-            policy_dir = Path(config_path).parent
+            # `config_path` may point at the checkpoint's train_config.json or at its
+            # pretrained_model/ directory (both documented above) — resolve either to
+            # the pretrained_model/ directory.
+            config_path_obj = Path(config_path)
+            policy_dir = config_path_obj.parent if config_path_obj.is_file() else config_path_obj
             self.checkpoint_path = policy_dir.parent
         elif self.job.is_remote:
             return

src/lerobot/datasets/dataset_tools.py

@@ -1045,10 +1045,12 @@ def _copy_data_with_feature_changes(
                     df[feature_name] = feature_values
                 else:
                     feature_slice = values[frame_idx:end_idx]
-                    if len(feature_slice.shape) > 1 and feature_slice.shape[1] == 1:
+                    if feature_slice.ndim == 1:
+                        df[feature_name] = feature_slice
+                    elif feature_slice.ndim == 2 and feature_slice.shape[1] == 1:
                         df[feature_name] = feature_slice.flatten()
                     else:
-                        df[feature_name] = feature_slice
+                        df[feature_name] = list(feature_slice)
             frame_idx = end_idx
 
         # Write using the same chunk/file structure as source

src/lerobot/datasets/pipeline_features.py

@@ -17,8 +17,8 @@ from collections.abc import Sequence
 from typing import Any
 
 from lerobot.configs import PipelineFeatureType
+from lerobot.lerobot_types import RobotAction, RobotObservation
 from lerobot.processor import DataProcessorPipeline
-from lerobot.types import RobotAction, RobotObservation
 from lerobot.utils.constants import ACTION, OBS_IMAGES, OBS_STATE, OBS_STR
 from lerobot.utils.feature_utils import hw_to_dataset_features
 

src/lerobot/datasets/streaming_dataset.py

@@ -58,6 +58,10 @@ class LookAheadError(Exception):
     pass
 
 
+class _ShardExhaustedError(Exception):
+    """Raised when a streaming dataset shard has no more items."""
+
+
 class Backtrackable[T]:
     """
     Wrap any iterator/iterable so you can step back up to `history` items
@@ -178,7 +182,7 @@ class Backtrackable[T]:
         """
         Check if we can go back `steps` items without raising an IndexError.
         """
-        return steps <= len(self._back_buf) + self._cursor
+        return steps < len(self._back_buf) + self._cursor
 
     def can_peek_ahead(self, steps: int = 1) -> bool:
         """
@@ -422,10 +426,7 @@ class StreamingLeRobotDataset(torch.utils.data.IterableDataset):
                     else:
                         frames_buffer.append(frame)
                     break  # random shard sampled, switch shard
-            except (
+            except _ShardExhaustedError:
-                RuntimeError,
-                StopIteration,
-            ):  # NOTE: StopIteration inside a generator throws a RuntimeError since python 3.7
                 del idx_to_backtrack_dataset[shard_key]  # Remove exhausted shard, onto another shard
 
         # Once shards are all exhausted, shuffle the buffer and yield the remaining frames
@@ -503,7 +504,11 @@ class StreamingLeRobotDataset(torch.utils.data.IterableDataset):
 
     def make_frame(self, dataset_iterator: Backtrackable) -> Generator:
         """Makes a frame starting from a dataset iterator"""
+        try:
             item = next(dataset_iterator)
+        except StopIteration as e:
+            # Translate exhaustion here, before PEP 479 turns it into an indistinguishable RuntimeError.
+            raise _ShardExhaustedError from e
         item = item_to_torch(item)
 
         updates = []  # list of "updates" to apply to the item retrieved from hf_dataset (w/o camera features)

src/lerobot/envs/configs.py

@@ -507,7 +507,7 @@ class MetaworldEnv(EnvConfig):
 class RoboCasaEnv(EnvConfig):
     task: str = "CloseFridge"
     fps: int = 20
-    episode_length: int = 1000
+    episode_length: int | None = None
     obs_type: str = "pixels_agent_pos"
     render_mode: str = "rgb_array"
     camera_name: str = "robot0_agentview_left,robot0_eye_in_hand,robot0_agentview_right"

src/lerobot/envs/libero.py

@@ -30,7 +30,7 @@ from gymnasium import spaces
 from libero.libero import benchmark, get_libero_path
 from libero.libero.envs import OffScreenRenderEnv
 
-from lerobot.types import RobotObservation
+from lerobot.lerobot_types import RobotObservation
 
 from .utils import _LazyAsyncVectorEnv, parse_camera_names
 

src/lerobot/envs/metaworld.py

@@ -25,7 +25,7 @@ import metaworld.policies as policies
 import numpy as np
 from gymnasium import spaces
 
-from lerobot.types import RobotObservation
+from lerobot.lerobot_types import RobotObservation
 
 from .utils import _LazyAsyncVectorEnv
 

src/lerobot/envs/robocasa.py

@@ -25,7 +25,7 @@ import gymnasium as gym
 import numpy as np
 from gymnasium import spaces
 
-from lerobot.types import RobotObservation
+from lerobot.lerobot_types import RobotObservation
 
 from .utils import _LazyAsyncVectorEnv, parse_camera_names
 
@@ -98,6 +98,19 @@ def _resolve_tasks(task: str) -> tuple[list[str], str | None]:
     return names, None
 
 
+def _get_task_horizon(task: str) -> int:
+    """Return the rollout horizon registered by RoboCasa for a task."""
+    from robocasa.utils.dataset_registry_utils import get_task_horizon
+
+    try:
+        return int(get_task_horizon(task))
+    except ValueError as exc:
+        raise ValueError(
+            f"No RoboCasa horizon is registered for task '{task}'. "
+            "Set `--env.episode_length=<steps>` explicitly."
+        ) from exc
+
+
 def convert_action(flat_action: np.ndarray) -> dict[str, Any]:
     """Split a flat (12,) action vector into a RoboCasa action dict.
 
@@ -154,7 +167,7 @@ class RoboCasaEnv(gym.Env):
 
         self.camera_name = parse_camera_names(camera_name)
 
-        self._max_episode_steps = episode_length if episode_length is not None else 1000
+        self._max_episode_steps = episode_length if episode_length is not None else _get_task_horizon(task)
 
         # Deferred — created on first reset() inside the worker subprocess
         # to avoid inheriting stale GPU/EGL contexts across fork().

src/lerobot/envs/robotwin.py

@@ -28,7 +28,7 @@ import numpy as np
 import torch
 from gymnasium import spaces
 
-from lerobot.types import RobotObservation
+from lerobot.lerobot_types import RobotObservation
 from lerobot.utils.import_utils import _scipy_available
 
 from .utils import _LazyAsyncVectorEnv

src/lerobot/envs/vlabench.py

@@ -37,7 +37,7 @@ import numpy as np
 from gymnasium import spaces
 from scipy.spatial.transform import Rotation
 
-from lerobot.types import RobotObservation
+from lerobot.lerobot_types import RobotObservation
 
 from .utils import _LazyAsyncVectorEnv
 

src/lerobot/policies/eo1/processor_eo1.py

@@ -22,6 +22,7 @@ from typing import TYPE_CHECKING, Any
 import torch
 
 from lerobot.configs.types import FeatureType, PipelineFeatureType, PolicyFeature
+from lerobot.lerobot_types import TransitionKey
 from lerobot.processor import (
     ComplementaryDataProcessorStep,
     PolicyAction,
@@ -31,7 +32,6 @@ from lerobot.processor import (
     make_default_policy_processor_steps,
     make_policy_processor_pipelines,
 )
-from lerobot.types import TransitionKey
 from lerobot.utils.constants import OBS_STATE
 from lerobot.utils.import_utils import _transformers_available, require_package
 

src/lerobot/policies/evo1/modeling_evo1.py

@@ -42,6 +42,9 @@ class Evo1Policy(PreTrainedPolicy):
     config_class = Evo1Config
     name = "evo1"
 
+    def supports_rtc(self) -> bool:
+        return True
+
     def __init__(self, config: Evo1Config, *, vlm_hub_kwargs: dict | None = None, **kwargs):
         super().__init__(config)
         config.validate_features()

src/lerobot/policies/evo1/processor_evo1.py

@@ -21,6 +21,7 @@ from typing import Any
 import torch
 
 from lerobot.configs import FeatureType, PipelineFeatureType, PolicyFeature
+from lerobot.lerobot_types import EnvTransition, TransitionKey
 from lerobot.processor import (
     AddBatchDimensionProcessorStep,
     DeviceProcessorStep,
@@ -40,7 +41,6 @@ from lerobot.processor.converters import (
     policy_action_to_transition,
     transition_to_policy_action,
 )
-from lerobot.types import EnvTransition, TransitionKey
 from lerobot.utils.constants import (
     ACTION,
     DONE,

src/lerobot/policies/factory.py

@@ -28,6 +28,7 @@ if TYPE_CHECKING:
 
 from lerobot.configs import FeatureType, PreTrainedConfig
 from lerobot.envs import EnvConfig, env_to_policy_features
+from lerobot.lerobot_types import PolicyAction
 from lerobot.processor import (
     AbsoluteActionsProcessorStep,
     PolicyProcessorPipeline,
@@ -37,7 +38,6 @@ from lerobot.processor import (
     transition_to_batch,
     transition_to_policy_action,
 )
-from lerobot.types import PolicyAction
 from lerobot.utils.constants import (
     ACTION,
     POLICY_POSTPROCESSOR_DEFAULT_NAME,

src/lerobot/policies/groot/modeling_groot.py

@@ -68,6 +68,9 @@ class GrootPolicy(PreTrainedPolicy):
     name = "groot"
     config_class = GrootConfig
 
+    def supports_rtc(self) -> bool:
+        return True
+
     def __init__(self, config: GrootConfig, **kwargs):
         """Initialize Groot policy wrapper."""
         require_package("transformers", extra="groot")

src/lerobot/policies/groot/processor_groot.py

@@ -50,6 +50,7 @@ if TYPE_CHECKING or _datasets_available:
 else:
     LeRobotDataset = None
 
+from lerobot.lerobot_types import EnvTransition, TransitionKey
 from lerobot.processor import (
     AbsoluteActionsProcessorStep,
     AddBatchDimensionProcessorStep,
@@ -66,7 +67,6 @@ from lerobot.processor import (
     transition_to_batch,
     transition_to_policy_action,
 )
-from lerobot.types import EnvTransition, TransitionKey
 from lerobot.utils.constants import (
     ACTION,
     OBS_IMAGE,

src/lerobot/policies/molmoact2/modeling_molmoact2.py

@@ -520,6 +520,9 @@ class MolmoAct2Policy(PreTrainedPolicy):
     config_class = MolmoAct2Config
     name = "molmoact2"
 
+    def supports_rtc(self) -> bool:
+        return self.config.inference_action_mode == "continuous"
+
     def __init__(
         self,
         config: MolmoAct2Config,

src/lerobot/policies/molmoact2/processor_molmoact2.py

@@ -36,6 +36,7 @@ import torch
 from torch import Tensor
 
 from lerobot.configs import FeatureType, PipelineFeatureType, PolicyFeature
+from lerobot.lerobot_types import EnvTransition, TransitionKey
 from lerobot.processor import (
     AddBatchDimensionProcessorStep,
     DeviceProcessorStep,
@@ -49,7 +50,6 @@ from lerobot.processor import (
     policy_action_to_transition,
     transition_to_policy_action,
 )
-from lerobot.types import EnvTransition, TransitionKey
 from lerobot.utils.constants import (
     ACTION,
     OBS_IMAGES,

src/lerobot/policies/pi0/modeling_pi0.py

@@ -749,6 +749,9 @@ class PI0Policy(PreTrainedPolicy):
     config_class = PI0Config
     name = "pi0"
 
+    def supports_rtc(self) -> bool:
+        return True
+
     def __init__(
         self,
         config: PI0Config,

src/lerobot/policies/pi05/modeling_pi05.py

@@ -714,6 +714,9 @@ class PI05Policy(PreTrainedPolicy):
     config_class = PI05Config
     name = "pi05"
 
+    def supports_rtc(self) -> bool:
+        return True
+
     def __init__(
         self,
         config: PI05Config,

src/lerobot/policies/pi05/processor_pi05.py

@@ -22,6 +22,7 @@ import numpy as np
 import torch
 
 from lerobot.configs import PipelineFeatureType, PolicyFeature
+from lerobot.lerobot_types import EnvTransition, TransitionKey
 from lerobot.processor import (
     AbsoluteActionsProcessorStep,
     PolicyAction,
@@ -33,7 +34,6 @@ from lerobot.processor import (
     make_default_policy_processor_steps,
     make_policy_processor_pipelines,
 )
-from lerobot.types import EnvTransition, TransitionKey
 from lerobot.utils.constants import OBS_STATE
 
 from .configuration_pi05 import PI05Config

src/lerobot/policies/pi0_fast/processor_pi0_fast.py

@@ -22,6 +22,7 @@ import numpy as np
 import torch
 
 from lerobot.configs import PipelineFeatureType, PolicyFeature
+from lerobot.lerobot_types import EnvTransition, TransitionKey
 from lerobot.processor import (
     AbsoluteActionsProcessorStep,
     ActionTokenizerProcessorStep,
@@ -34,7 +35,6 @@ from lerobot.processor import (
     make_default_policy_processor_steps,
     make_policy_processor_pipelines,
 )
-from lerobot.types import EnvTransition, TransitionKey
 from lerobot.utils.constants import OBS_STATE
 
 from .configuration_pi0_fast import PI0FastConfig

src/lerobot/policies/pretrained.py

@@ -249,6 +249,10 @@ class PreTrainedPolicy(nn.Module, HubMixin, abc.ABC):
         """
         raise NotImplementedError
 
+    def supports_rtc(self) -> bool:
+        """Whether this policy implements Real-Time Chunking inference semantics."""
+        return False
+
     # TODO(aliberts, rcadene): split into 'forward' and 'compute_loss'?
     @abc.abstractmethod
     def forward(self, batch: dict[str, Tensor]) -> tuple[Tensor, dict | None]:

src/lerobot/policies/smolvla/modeling_smolvla.py

@@ -145,6 +145,9 @@ class SmolVLAPolicy(PreTrainedPolicy):
     config_class = SmolVLAConfig
     name = "smolvla"
 
+    def supports_rtc(self) -> bool:
+        return True
+
     def __init__(
         self,
         config: SmolVLAConfig,

src/lerobot/policies/smolvla/smolvlm_with_expert.py

@@ -168,14 +168,23 @@ class SmolVLMWithExpertModel(nn.Module):
                 last_layers.append(self.num_vlm_layers - 2)
             frozen_layers = [
                 "lm_head",
-                "text_model.model.norm.weight",
+                "text_model.norm.weight",
             ]
             for layer in last_layers:
-                frozen_layers.append(f"text_model.model.layers.{layer}.")
+                frozen_layers.append(f"text_model.layers.{layer}.")
 
+            unmatched_patterns = set(frozen_layers)
             for name, params in self.vlm.named_parameters():
-                if any(k in name for k in frozen_layers):
+                matched_patterns = [k for k in frozen_layers if k in name]
+                if matched_patterns:
                     params.requires_grad = False
+                    unmatched_patterns.difference_update(matched_patterns)
+            if unmatched_patterns:
+                raise RuntimeError(
+                    "Some frozen layer patterns matched no VLM parameters, so the corresponding layers "
+                    "would silently remain trainable (parameter naming may have changed in transformers): "
+                    f"{sorted(unmatched_patterns)}"
+                )
         # To avoid unused params issue with distributed training
         for name, params in self.lm_expert.named_parameters():
             if "lm_head" in name:

src/lerobot/policies/utils.py

@@ -22,7 +22,7 @@ import torch
 from torch import nn
 
 from lerobot.configs import FeatureType, PolicyFeature, PreTrainedConfig
-from lerobot.types import PolicyAction, RobotAction, RobotObservation
+from lerobot.lerobot_types import PolicyAction, RobotAction, RobotObservation
 from lerobot.utils.constants import ACTION, OBS_STR
 from lerobot.utils.feature_utils import build_dataset_frame
 

src/lerobot/policies/xvla/modeling_xvla.py

@@ -150,7 +150,7 @@ class XVLAModel(nn.Module):
         # Freeze or unfreeze policy transformer
         if not self.config.train_policy_transformer:
             for name, param in self.transformer.named_parameters():
-                if "soft_prompts" not in name:
+                if "soft_prompt" not in name:
                     param.requires_grad = False
 
         # Freeze or unfreeze soft prompts

src/lerobot/policies/xvla/processor_xvla.py

@@ -21,6 +21,7 @@ import numpy as np
 import torch
 
 from lerobot.configs import PipelineFeatureType, PolicyFeature
+from lerobot.lerobot_types import EnvTransition, TransitionKey
 from lerobot.processor import (
     ObservationProcessorStep,
     PolicyAction,
@@ -31,7 +32,6 @@ from lerobot.processor import (
     make_default_policy_processor_steps,
     make_policy_processor_pipelines,
 )
-from lerobot.types import EnvTransition, TransitionKey
 from lerobot.utils.constants import (
     IMAGENET_STATS,
     OBS_IMAGES,

src/lerobot/processor/__init__.py

@@ -14,7 +14,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from lerobot.types import (
+from lerobot.lerobot_types import (
     EnvAction,
     EnvTransition,
     PolicyAction,

src/lerobot/processor/batch_processor.py

@@ -25,7 +25,7 @@ from dataclasses import dataclass, field
 from torch import Tensor
 
 from lerobot.configs import PipelineFeatureType, PolicyFeature
-from lerobot.types import EnvTransition, PolicyAction
+from lerobot.lerobot_types import EnvTransition, PolicyAction
 from lerobot.utils.constants import OBS_ENV_STATE, OBS_IMAGE, OBS_IMAGES, OBS_STATE
 
 from .pipeline import (

src/lerobot/processor/converters.py

@@ -23,7 +23,7 @@ from typing import Any
 import numpy as np
 import torch
 
-from lerobot.types import EnvTransition, PolicyAction, RobotAction, RobotObservation, TransitionKey
+from lerobot.lerobot_types import EnvTransition, PolicyAction, RobotAction, RobotObservation, TransitionKey
 from lerobot.utils.constants import ACTION, DONE, INFO, OBS_PREFIX, REWARD, TRUNCATED
 
 

src/lerobot/processor/delta_action_processor.py

@@ -17,7 +17,7 @@
 from dataclasses import dataclass
 
 from lerobot.configs import FeatureType, PipelineFeatureType, PolicyFeature
-from lerobot.types import PolicyAction, RobotAction
+from lerobot.lerobot_types import PolicyAction, RobotAction
 
 from .pipeline import ActionProcessorStep, ProcessorStepRegistry, RobotActionProcessorStep
 

src/lerobot/processor/device_processor.py

@@ -25,7 +25,7 @@ from typing import Any
 import torch
 
 from lerobot.configs import PipelineFeatureType, PolicyFeature
-from lerobot.types import EnvTransition, PolicyAction, TransitionKey
+from lerobot.lerobot_types import EnvTransition, PolicyAction, TransitionKey
 from lerobot.utils.device_utils import get_safe_torch_device
 
 from .pipeline import ProcessorStep, ProcessorStepRegistry

src/lerobot/processor/factory.py

@@ -20,7 +20,7 @@ from typing import Any
 import torch
 
 from lerobot.configs.policies import PreTrainedConfig
-from lerobot.types import PolicyAction, RobotAction, RobotObservation
+from lerobot.lerobot_types import PolicyAction, RobotAction, RobotObservation
 from lerobot.utils.constants import POLICY_POSTPROCESSOR_DEFAULT_NAME, POLICY_PREPROCESSOR_DEFAULT_NAME
 
 from .batch_processor import AddBatchDimensionProcessorStep

src/lerobot/processor/gym_action_processor.py

@@ -17,7 +17,7 @@
 from dataclasses import dataclass
 
 from lerobot.configs import PipelineFeatureType, PolicyFeature
-from lerobot.types import EnvAction, EnvTransition, PolicyAction, TransitionKey
+from lerobot.lerobot_types import EnvAction, EnvTransition, PolicyAction, TransitionKey
 
 from .converters import to_tensor
 from .hil_processor import TELEOP_ACTION_KEY

src/lerobot/processor/hil_processor.py

@@ -29,7 +29,7 @@ from lerobot.teleoperators.utils import TeleopEvents
 if TYPE_CHECKING:
     from lerobot.teleoperators.teleoperator import Teleoperator
 
-from lerobot.types import EnvTransition, PolicyAction, TransitionKey
+from lerobot.lerobot_types import EnvTransition, PolicyAction, TransitionKey
 
 from .pipeline import (
     ComplementaryDataProcessorStep,

src/lerobot/processor/normalize_processor.py

@@ -25,7 +25,7 @@ import torch
 from torch import Tensor
 
 from lerobot.configs import FeatureType, NormalizationMode, PipelineFeatureType, PolicyFeature
-from lerobot.types import EnvTransition, PolicyAction, TransitionKey
+from lerobot.lerobot_types import EnvTransition, PolicyAction, TransitionKey
 
 if TYPE_CHECKING:
     from lerobot.datasets import LeRobotDataset

src/lerobot/processor/pipeline.py

@@ -45,7 +45,14 @@ from huggingface_hub import hf_hub_download
 from safetensors.torch import load_file, save_file
 
 from lerobot.configs import PipelineFeatureType, PolicyFeature
-from lerobot.types import EnvAction, EnvTransition, PolicyAction, RobotAction, RobotObservation, TransitionKey
+from lerobot.lerobot_types import (
+    EnvAction,
+    EnvTransition,
+    PolicyAction,
+    RobotAction,
+    RobotObservation,
+    TransitionKey,
+)
 from lerobot.utils.constants import HF_LEROBOT_HOME
 from lerobot.utils.hub import HubMixin
 

src/lerobot/processor/policy_robot_bridge.py

@@ -20,7 +20,7 @@ from typing import Any
 import torch
 
 from lerobot.configs import FeatureType, PipelineFeatureType, PolicyFeature
-from lerobot.types import PolicyAction, RobotAction
+from lerobot.lerobot_types import PolicyAction, RobotAction
 from lerobot.utils.constants import ACTION
 
 from .pipeline import ActionProcessorStep, ProcessorStepRegistry

src/lerobot/processor/relative_action_processor.py

@@ -20,7 +20,7 @@ import torch
 from torch import Tensor
 
 from lerobot.configs import PipelineFeatureType, PolicyFeature
-from lerobot.types import EnvTransition, TransitionKey
+from lerobot.lerobot_types import EnvTransition, TransitionKey
 from lerobot.utils.constants import OBS_STATE
 
 from .delta_action_processor import MapDeltaActionToRobotActionStep, MapTensorToDeltaActionDictStep

src/lerobot/processor/render_messages_processor.py

@@ -23,7 +23,7 @@ from lerobot.configs import PipelineFeatureType, PolicyFeature
 from lerobot.configs.recipe import TrainingRecipe
 from lerobot.datasets.language import LANGUAGE_EVENTS, LANGUAGE_PERSISTENT
 from lerobot.datasets.language_render import render_sample
-from lerobot.types import EnvTransition, TransitionKey
+from lerobot.lerobot_types import EnvTransition, TransitionKey
 from lerobot.utils.utils import unwrap_scalar
 
 from .pipeline import ProcessorStep, ProcessorStepRegistry

src/lerobot/processor/tokenizer_processor.py

@@ -30,7 +30,7 @@ from typing import TYPE_CHECKING, Any
 import torch
 
 from lerobot.configs import FeatureType, PipelineFeatureType, PolicyFeature
-from lerobot.types import EnvTransition, RobotObservation, TransitionKey
+from lerobot.lerobot_types import EnvTransition, RobotObservation, TransitionKey
 from lerobot.utils.constants import (
     ACTION_TOKEN_MASK,
     ACTION_TOKENS,

src/lerobot/rewards/robometer/compute_rabc_weights.py

@@ -57,10 +57,10 @@ import torch
 from tqdm import tqdm
 
 from lerobot.datasets import LeRobotDataset
+from lerobot.lerobot_types import TransitionKey
 from lerobot.rewards.robometer.configuration_robometer import RobometerConfig
 from lerobot.rewards.robometer.modeling_robometer import RobometerRewardModel
 from lerobot.rewards.robometer.processor_robometer import RobometerEncoderProcessorStep
-from lerobot.types import TransitionKey
 
 DEFAULT_OUTPUT_FILENAME = "robometer_progress.parquet"
 

src/lerobot/rewards/robometer/processor_robometer.py

@@ -25,6 +25,7 @@ from PIL import Image
 from torch import Tensor
 
 from lerobot.configs import PipelineFeatureType, PolicyFeature
+from lerobot.lerobot_types import EnvTransition, TransitionKey
 from lerobot.processor import (
     AddBatchDimensionProcessorStep,
     DeviceProcessorStep,
@@ -39,7 +40,6 @@ from lerobot.rewards.robometer.configuration_robometer import (
     RobometerConfig,
 )
 from lerobot.rewards.robometer.modeling_robometer import ROBOMETER_FEATURE_PREFIX
-from lerobot.types import EnvTransition, TransitionKey
 from lerobot.utils.constants import (
     OBS_IMAGES,
     POLICY_POSTPROCESSOR_DEFAULT_NAME,

src/lerobot/rewards/sarm/processor_sarm.py

@@ -47,6 +47,7 @@ else:
     Faker = None  # type: ignore[assignment, misc]
 
 from lerobot.configs import FeatureType, PipelineFeatureType, PolicyFeature
+from lerobot.lerobot_types import EnvTransition, PolicyAction, TransitionKey
 from lerobot.processor import (
     AddBatchDimensionProcessorStep,
     DeviceProcessorStep,
@@ -58,7 +59,6 @@ from lerobot.processor import (
     policy_action_to_transition,
     transition_to_policy_action,
 )
-from lerobot.types import EnvTransition, PolicyAction, TransitionKey
 from lerobot.utils.constants import POLICY_POSTPROCESSOR_DEFAULT_NAME, POLICY_PREPROCESSOR_DEFAULT_NAME
 
 from .configuration_sarm import SARMConfig

src/lerobot/rewards/topreward/compute_rabc_weights.py

@@ -48,10 +48,10 @@ import torch
 from tqdm import tqdm
 
 from lerobot.datasets import LeRobotDataset
+from lerobot.lerobot_types import TransitionKey
 from lerobot.rewards.topreward.configuration_topreward import TOPRewardConfig
 from lerobot.rewards.topreward.modeling_topreward import TOPRewardModel
 from lerobot.rewards.topreward.processor_topreward import TOPRewardEncoderProcessorStep
-from lerobot.types import TransitionKey
 
 DEFAULT_OUTPUT_FILENAME = "topreward_progress.parquet"
 

src/lerobot/rewards/topreward/processor_topreward.py

@@ -23,6 +23,7 @@ import torch
 from torch import Tensor
 
 from lerobot.configs import PipelineFeatureType, PolicyFeature
+from lerobot.lerobot_types import EnvTransition, TransitionKey
 from lerobot.processor import (
     AddBatchDimensionProcessorStep,
     DeviceProcessorStep,
@@ -37,7 +38,6 @@ from lerobot.rewards.topreward.configuration_topreward import (
     DEFAULT_PROMPT_SUFFIX_TEMPLATE,
     TOPRewardConfig,
 )
-from lerobot.types import EnvTransition, TransitionKey
 from lerobot.utils.constants import (
     OBS_IMAGES,
     OBS_PREFIX,

src/lerobot/rl/algorithms/base.py

@@ -28,7 +28,7 @@ from huggingface_hub.errors import HfHubHTTPError
 from safetensors.torch import load_file as load_safetensors, save_file as save_safetensors
 from torch.optim import Optimizer
 
-from lerobot.types import BatchType
+from lerobot.lerobot_types import BatchType
 from lerobot.utils.hub import HubMixin
 
 from .configs import RLAlgorithmConfig, TrainingStats

src/lerobot/rl/algorithms/configs.py

@@ -16,6 +16,7 @@ from __future__ import annotations
 
 import abc
 import builtins
+import json
 import logging
 import os
 from dataclasses import dataclass, field
@@ -78,8 +79,10 @@ class RLAlgorithmConfig(draccus.ChoiceRegistry, HubMixin, abc.ABC):
 
     def _save_pretrained(self, save_directory: Path) -> None:
         """Serialize this config as ``config.json`` inside ``save_directory``."""
-        with open(save_directory / CONFIG_NAME, "w") as f, draccus.config_type("json"):
+        # Encode against the base class so draccus includes the choice "type" key,
-            draccus.dump(self, f, indent=4)
+        # which `from_pretrained` needs to resolve the concrete subclass.
+        with open(save_directory / CONFIG_NAME, "w") as f:
+            json.dump(draccus.encode(self, RLAlgorithmConfig), f, indent=4)
 
     @classmethod
     def from_pretrained(

src/lerobot/rl/algorithms/sac/sac_algorithm.py

@@ -26,6 +26,7 @@ import torch.nn.functional as F  # noqa: N812
 from torch import Tensor
 from torch.optim import Optimizer
 
+from lerobot.lerobot_types import BatchType
 from lerobot.policies.gaussian_actor.modeling_gaussian_actor import (
     DISCRETE_DIMENSION_INDEX,
     MLP,
@@ -35,7 +36,6 @@ from lerobot.policies.gaussian_actor.modeling_gaussian_actor import (
     orthogonal_init,
 )
 from lerobot.policies.utils import get_device_from_parameters
-from lerobot.types import BatchType
 from lerobot.utils.constants import ACTION
 from lerobot.utils.transition import move_state_dict_to_device
 

src/lerobot/rl/data_sources/__init__.py

@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from lerobot.types import BatchType
+from lerobot.lerobot_types import BatchType
 
 from .data_mixer import DataMixer, OnlineOfflineMixer
 

src/lerobot/rl/data_sources/data_mixer.py

@@ -16,7 +16,7 @@ from __future__ import annotations
 
 import abc
 
-from lerobot.types import BatchType
+from lerobot.lerobot_types import BatchType
 
 from ..buffer import ReplayBuffer, concatenate_batch_transitions
 

src/lerobot/rl/trainer.py

@@ -17,7 +17,7 @@ from __future__ import annotations
 from collections.abc import Iterator
 from typing import Any
 
-from lerobot.types import BatchType
+from lerobot.lerobot_types import BatchType
 
 from .algorithms.base import RLAlgorithm
 from .algorithms.configs import TrainingStats

src/lerobot/robots/bi_openarm_follower/bi_openarm_follower.py

@@ -17,7 +17,7 @@
 import logging
 from functools import cached_property
 
-from lerobot.types import RobotAction, RobotObservation
+from lerobot.lerobot_types import RobotAction, RobotObservation
 from lerobot.utils.bimanual import BimanualMixin
 from lerobot.utils.decorators import check_if_not_connected
 

src/lerobot/robots/bi_rebot_b601_follower/bi_rebot_b601_follower.py

@@ -17,7 +17,7 @@
 import logging
 from functools import cached_property
 
-from lerobot.types import RobotAction, RobotObservation
+from lerobot.lerobot_types import RobotAction, RobotObservation
 from lerobot.utils.bimanual import BimanualMixin
 from lerobot.utils.decorators import check_if_not_connected
 

src/lerobot/robots/bi_so_follower/bi_so_follower.py

@@ -17,7 +17,7 @@
 import logging
 from functools import cached_property
 
-from lerobot.types import RobotAction, RobotObservation
+from lerobot.lerobot_types import RobotAction, RobotObservation
 from lerobot.utils.bimanual import BimanualMixin
 from lerobot.utils.decorators import check_if_not_connected
 
@@ -62,6 +62,7 @@ class BiSOFollower(BimanualMixin, Robot):
             position_i_coefficient=config.left_arm_config.position_i_coefficient,
             position_d_coefficient=config.left_arm_config.position_d_coefficient,
             use_degrees=config.left_arm_config.use_degrees,
+            num_read_retries=config.left_arm_config.num_read_retries,
             cameras=left_arm_cameras,
         )
 
@@ -75,6 +76,7 @@ class BiSOFollower(BimanualMixin, Robot):
             position_i_coefficient=config.right_arm_config.position_i_coefficient,
             position_d_coefficient=config.right_arm_config.position_d_coefficient,
             use_degrees=config.right_arm_config.use_degrees,
+            num_read_retries=config.right_arm_config.num_read_retries,
             cameras=config.right_arm_config.cameras,
         )
 

src/lerobot/robots/earthrover_mini_plus/robot_earthrover_mini_plus.py

@@ -23,7 +23,7 @@ import cv2
 import numpy as np
 import requests
 
-from lerobot.types import RobotAction, RobotObservation
+from lerobot.lerobot_types import RobotAction, RobotObservation
 from lerobot.utils.decorators import check_if_already_connected, check_if_not_connected
 from lerobot.utils.errors import DeviceNotConnectedError
 

src/lerobot/robots/hope_jr/hope_jr_arm.py

@@ -19,12 +19,12 @@ import time
 from functools import cached_property
 
 from lerobot.cameras import make_cameras_from_configs
+from lerobot.lerobot_types import RobotAction, RobotObservation
 from lerobot.motors import Motor, MotorNormMode
 from lerobot.motors.calibration_gui import RangeFinderGUI
 from lerobot.motors.feetech import (
     FeetechMotorsBus,
 )
-from lerobot.types import RobotAction, RobotObservation
 from lerobot.utils.decorators import check_if_already_connected, check_if_not_connected
 
 from ..robot import Robot

src/lerobot/robots/hope_jr/hope_jr_hand.py

@@ -19,12 +19,12 @@ import time
 from functools import cached_property
 
 from lerobot.cameras import make_cameras_from_configs
+from lerobot.lerobot_types import RobotAction, RobotObservation
 from lerobot.motors import Motor, MotorNormMode
 from lerobot.motors.calibration_gui import RangeFinderGUI
 from lerobot.motors.feetech import (
     FeetechMotorsBus,
 )
-from lerobot.types import RobotAction, RobotObservation
 from lerobot.utils.decorators import check_if_already_connected, check_if_not_connected
 
 from ..robot import Robot

src/lerobot/robots/koch_follower/koch_follower.py

@@ -19,12 +19,12 @@ import time
 from functools import cached_property
 
 from lerobot.cameras import make_cameras_from_configs
+from lerobot.lerobot_types import RobotAction, RobotObservation
 from lerobot.motors import Motor, MotorCalibration, MotorNormMode
 from lerobot.motors.dynamixel import (
     DynamixelMotorsBus,
     OperatingMode,
 )
-from lerobot.types import RobotAction, RobotObservation
 from lerobot.utils.decorators import check_if_already_connected, check_if_not_connected
 
 from ..robot import Robot

src/lerobot/robots/lekiwi/config_lekiwi.py

@@ -23,10 +23,20 @@ from ..config import RobotConfig
 def lekiwi_cameras_config() -> dict[str, CameraConfig]:
     return {
         "front": OpenCVCameraConfig(
-            index_or_path="/dev/video0", fps=30, width=640, height=480, rotation=Cv2Rotation.ROTATE_180
+            index_or_path="/dev/video0",
+            fps=30,
+            width=640,
+            height=480,
+            fourcc="MJPG",
+            rotation=Cv2Rotation.ROTATE_180,
         ),
         "wrist": OpenCVCameraConfig(
-            index_or_path="/dev/video2", fps=30, width=480, height=640, rotation=Cv2Rotation.ROTATE_90
+            index_or_path="/dev/video2",
+            fps=30,
+            width=480,
+            height=640,
+            fourcc="MJPG",
+            rotation=Cv2Rotation.ROTATE_90,
         ),
     }
 

src/lerobot/robots/lekiwi/lekiwi.py

@@ -23,12 +23,12 @@ from typing import Any
 import numpy as np
 
 from lerobot.cameras import make_cameras_from_configs
+from lerobot.lerobot_types import RobotAction, RobotObservation
 from lerobot.motors import Motor, MotorCalibration, MotorNormMode
 from lerobot.motors.feetech import (
     FeetechMotorsBus,
     OperatingMode,
 )
-from lerobot.types import RobotAction, RobotObservation
 from lerobot.utils.decorators import check_if_already_connected, check_if_not_connected
 
 from ..robot import Robot

src/lerobot/robots/lekiwi/lekiwi_client.py

@@ -14,7 +14,6 @@
 
 # TODO(aliberts, Steven, Pepijn): use gRPC calls instead of zmq?
 
-import base64
 import json
 import logging
 from functools import cached_property
@@ -22,7 +21,7 @@ from functools import cached_property
 import cv2
 import numpy as np
 
-from lerobot.types import RobotAction, RobotObservation
+from lerobot.lerobot_types import RobotAction, RobotObservation
 from lerobot.utils.constants import ACTION, OBS_STATE
 from lerobot.utils.decorators import check_if_already_connected, check_if_not_connected
 from lerobot.utils.errors import DeviceNotConnectedError
@@ -134,7 +133,9 @@ class LeKiwiClient(Robot):
         self.zmq_observation_socket = self.zmq_context.socket(zmq.PULL)
         zmq_observations_locator = f"tcp://{self.remote_ip}:{self.port_zmq_observations}"
         self.zmq_observation_socket.connect(zmq_observations_locator)
-        self.zmq_observation_socket.setsockopt(zmq.CONFLATE, 1)
+        # CONFLATE does not support multipart messages; a small receive queue plus
+        # the existing drain-to-latest loop keeps newest-only semantics.
+        self.zmq_observation_socket.setsockopt(zmq.RCVHWM, 2)
 
         poller = zmq.Poller()
         poller.register(self.zmq_observation_socket, zmq.POLLIN)
@@ -147,8 +148,8 @@ class LeKiwiClient(Robot):
     def calibrate(self) -> None:
         pass
 
-    def _poll_and_get_latest_message(self) -> str | None:
+    def _poll_and_get_latest_message(self) -> list[bytes] | None:
-        """Polls the ZMQ socket for a limited time and returns the latest message string."""
+        """Polls the ZMQ socket for a limited time and returns the latest message's frames."""
         zmq = self._zmq
         poller = zmq.Poller()
         poller.register(self.zmq_observation_socket, zmq.POLLIN)
@@ -166,7 +167,7 @@ class LeKiwiClient(Robot):
         last_msg = None
         while True:
             try:
-                msg = self.zmq_observation_socket.recv_string(zmq.NOBLOCK)
+                msg = self.zmq_observation_socket.recv_multipart(zmq.NOBLOCK)
                 last_msg = msg
             except zmq.Again:
                 break
@@ -176,28 +177,27 @@ class LeKiwiClient(Robot):
 
         return last_msg
 
-    def _parse_observation_json(self, obs_string: str) -> RobotObservation | None:
+    def _parse_observation(self, frames: list[bytes]) -> RobotObservation | None:
-        """Parses the JSON observation string."""
+        """Parses a multipart observation: JSON header + one raw JPEG frame per camera."""
         try:
-            return json.loads(obs_string)
+            header = json.loads(frames[0])
-        except json.JSONDecodeError as e:
+            cam_names = header.pop("_cams")
-            logging.error(f"Error decoding JSON observation: {e}")
+            observation: RobotObservation = header
+            for cam_name, jpeg in zip(cam_names, frames[1:], strict=True):
+                observation[cam_name] = jpeg
+            return observation
+        except (json.JSONDecodeError, KeyError, ValueError) as e:
+            logging.error(f"Error decoding observation: {e}")
             return None
 
-    def _decode_image_from_b64(self, image_b64: str) -> np.ndarray | None:
+    def _decode_image(self, jpeg: bytes) -> np.ndarray | None:
-        """Decodes a base64 encoded image string to an OpenCV image."""
+        """Decodes a raw JPEG buffer to an OpenCV image."""
-        if not image_b64:
+        if not jpeg:
             return None
-        try:
+        frame = cv2.imdecode(np.frombuffer(jpeg, dtype=np.uint8), cv2.IMREAD_COLOR)
-            jpg_data = base64.b64decode(image_b64)
-            np_arr = np.frombuffer(jpg_data, dtype=np.uint8)
-            frame = cv2.imdecode(np_arr, cv2.IMREAD_COLOR)
         if frame is None:
             logging.warning("cv2.imdecode returned None for an image.")
         return frame
-        except (TypeError, ValueError) as e:
-            logging.error(f"Error decoding base64 image data: {e}")
-            return None
 
     def _remote_state_from_obs(
         self, observation: RobotObservation
@@ -212,10 +212,10 @@ class LeKiwiClient(Robot):
 
         # Decode images
         current_frames: dict[str, np.ndarray] = {}
-        for cam_name, image_b64 in observation.items():
+        for cam_name, jpeg in observation.items():
             if cam_name not in self._cameras_ft:
                 continue
-            frame = self._decode_image_from_b64(image_b64)
+            frame = self._decode_image(jpeg)
             if frame is not None:
                 current_frames[cam_name] = frame
 
@@ -230,15 +230,15 @@ class LeKiwiClient(Robot):
         If no new data arrives or decoding fails, returns the last known values.
         """
 
-        # 1. Get the latest message string from the socket
+        # 1. Get the latest message's frames from the socket
-        latest_message_str = self._poll_and_get_latest_message()
+        latest_frames = self._poll_and_get_latest_message()
 
         # 2. If no message, return cached data
-        if latest_message_str is None:
+        if latest_frames is None:
             return self.last_frames, self.last_remote_state
 
-        # 3. Parse the JSON message
+        # 3. Parse the multipart message
-        observation = self._parse_observation_json(latest_message_str)
+        observation = self._parse_observation(latest_frames)
 
         # 4. If JSON parsing failed, return cached data
         if observation is None:

src/lerobot/robots/lekiwi/lekiwi_host.py

@@ -14,7 +14,6 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import base64
 import json
 import logging
 import time
@@ -44,7 +43,9 @@ class LeKiwiHost:
         self.zmq_cmd_socket.bind(f"tcp://*:{config.port_zmq_cmd}")
 
         self.zmq_observation_socket = self.zmq_context.socket(zmq.PUSH)
-        self.zmq_observation_socket.setsockopt(zmq.CONFLATE, 1)
+        # CONFLATE does not support multipart messages; a 2-deep send queue keeps
+        # near-latest-only semantics and sheds stale observations during stalls.
+        self.zmq_observation_socket.setsockopt(zmq.SNDHWM, 2)
         self.zmq_observation_socket.bind(f"tcp://*:{config.port_zmq_observations}")
 
         self.connection_time_s = config.connection_time_s
@@ -99,19 +100,23 @@ def main(cfg: LeKiwiServerConfig):
 
             last_observation = robot.get_observation()
 
-            # Encode ndarrays to base64 strings
+            # Send one multipart message: a JSON header frame (state + camera
-            for cam_key, _ in robot.cameras.items():
+            # order) followed by one raw JPEG frame per camera. Raw JPEG avoids
-                ret, buffer = cv2.imencode(
+            # the 33% base64 inflation of embedding binary data in JSON.
-                    ".jpg", last_observation[cam_key], [int(cv2.IMWRITE_JPEG_QUALITY), 90]
+            cam_keys = list(robot.cameras.keys())
+            jpeg_frames = []
+            for cam_key in cam_keys:
+                ret, jpeg = cv2.imencode(
+                    ".jpg", last_observation.pop(cam_key), [int(cv2.IMWRITE_JPEG_QUALITY), 90]
                 )
-                if ret:
+                jpeg_frames.append(jpeg if ret else b"")
-                    last_observation[cam_key] = base64.b64encode(buffer).decode("utf-8")
+            header = {"_cams": cam_keys, **last_observation}
-                else:
-                    last_observation[cam_key] = ""
 
             # Send the observation to the remote agent
             try:
-                host.zmq_observation_socket.send_string(json.dumps(last_observation), flags=zmq.NOBLOCK)
+                host.zmq_observation_socket.send_multipart(
+                    [json.dumps(header).encode()] + jpeg_frames, flags=zmq.NOBLOCK
+                )
             except zmq.Again:
                 logging.info("Dropping observation, no client connected")
 

src/lerobot/robots/omx_follower/omx_follower.py

@@ -19,13 +19,13 @@ import time
 from functools import cached_property
 
 from lerobot.cameras import make_cameras_from_configs
+from lerobot.lerobot_types import RobotAction, RobotObservation
 from lerobot.motors import Motor, MotorCalibration, MotorNormMode
 from lerobot.motors.dynamixel import (
     DriveMode,
     DynamixelMotorsBus,
     OperatingMode,
 )
-from lerobot.types import RobotAction, RobotObservation
 from lerobot.utils.decorators import check_if_already_connected, check_if_not_connected
 
 from ..robot import Robot

src/lerobot/robots/openarm_follower/openarm_follower.py

@@ -20,9 +20,9 @@ from functools import cached_property
 from typing import Any
 
 from lerobot.cameras import make_cameras_from_configs
+from lerobot.lerobot_types import RobotAction, RobotObservation
 from lerobot.motors import Motor, MotorCalibration, MotorNormMode
 from lerobot.motors.damiao import DamiaoMotorsBus
-from lerobot.types import RobotAction, RobotObservation
 from lerobot.utils.decorators import check_if_already_connected, check_if_not_connected
 
 from ..robot import Robot

src/lerobot/robots/reachy2/robot_reachy2.py

@@ -19,7 +19,7 @@ import time
 from typing import TYPE_CHECKING, Any
 
 from lerobot.cameras import make_cameras_from_configs
-from lerobot.types import RobotAction, RobotObservation
+from lerobot.lerobot_types import RobotAction, RobotObservation
 from lerobot.utils.import_utils import _reachy2_sdk_available, require_package
 
 from ..robot import Robot

src/lerobot/robots/rebot_b601_follower/rebot_b601_follower.py

@@ -21,8 +21,8 @@ from functools import cached_property
 from typing import TYPE_CHECKING
 
 from lerobot.cameras import make_cameras_from_configs
+from lerobot.lerobot_types import RobotAction, RobotObservation
 from lerobot.motors import MotorCalibration
-from lerobot.types import RobotAction, RobotObservation
 from lerobot.utils.decorators import check_if_already_connected, check_if_not_connected
 from lerobot.utils.import_utils import _motorbridge_available, require_package
 

src/lerobot/robots/robot.py

@@ -18,8 +18,8 @@ from pathlib import Path
 
 import draccus
 
+from lerobot.lerobot_types import RobotAction, RobotObservation
 from lerobot.motors import MotorCalibration
-from lerobot.types import RobotAction, RobotObservation
 from lerobot.utils.constants import HF_LEROBOT_CALIBRATION, ROBOTS
 
 from .config import RobotConfig

src/lerobot/robots/so_follower/so_follower.py

@@ -19,12 +19,12 @@ import time
 from functools import cached_property
 
 from lerobot.cameras import make_cameras_from_configs
+from lerobot.lerobot_types import RobotAction, RobotObservation
 from lerobot.motors import Motor, MotorCalibration, MotorNormMode
 from lerobot.motors.feetech import (
     FeetechMotorsBus,
     OperatingMode,
 )
-from lerobot.types import RobotAction, RobotObservation
 from lerobot.utils.decorators import check_if_already_connected, check_if_not_connected
 
 from ..robot import Robot

src/lerobot/robots/unitree_g1/unitree_g1.py

@@ -26,7 +26,7 @@ from typing import TYPE_CHECKING, Protocol, runtime_checkable
 import numpy as np
 
 from lerobot.cameras import make_cameras_from_configs
-from lerobot.types import RobotAction, RobotObservation
+from lerobot.lerobot_types import RobotAction, RobotObservation
 from lerobot.utils.import_utils import _unitree_sdk_available, require_package
 
 from ..robot import Robot

src/lerobot/rollout/context.py

@@ -57,6 +57,7 @@ from .inference import (
     SyncInferenceConfig,
     create_inference_engine,
 )
+from .inference.rtc import supports_rtc_inference
 from .robot_wrapper import ThreadSafeRobot
 
 if TYPE_CHECKING or _peft_available:
@@ -226,6 +227,12 @@ def build_rollout_context(
     policy = _load_pretrained_policy(policy_config)
 
     if is_rtc:
+        if not supports_rtc_inference(policy):
+            raise ValueError(
+                f"RTC inference is not supported by policy type '{policy_config.type}': "
+                "the policy must implement RTC semantics and predict_action_chunk must accept "
+                "inference_delay and prev_chunk_left_over. Use '--inference.type=sync' instead."
+            )
         policy.config.rtc_config = cfg.inference.rtc
         if hasattr(policy, "init_rtc_processor"):
             policy.init_rtc_processor()

src/lerobot/rollout/inference/rtc.py

@@ -22,6 +22,7 @@ way via ``notify_observation``.
 
 from __future__ import annotations
 
+import inspect
 import logging
 import math
 import time
@@ -62,6 +63,23 @@ _RTC_JOIN_TIMEOUT_S: float = 3.0
 # ---------------------------------------------------------------------------
 
 
+def supports_rtc_inference(policy: PreTrainedPolicy) -> bool:
+    """Whether a policy declares RTC support and accepts the RTC call shape."""
+    supports_rtc = getattr(policy, "supports_rtc", None)
+    if not callable(supports_rtc) or not supports_rtc():
+        return False
+
+    try:
+        inspect.signature(policy.predict_action_chunk).bind(
+            object(),
+            inference_delay=0,
+            prev_chunk_left_over=None,
+        )
+    except (TypeError, ValueError):
+        return False
+    return True
+
+
 def _normalize_prev_actions_length(prev_actions: torch.Tensor, target_steps: int) -> torch.Tensor:
     """Pad or truncate RTC prefix actions to a fixed length for stable compiled inference."""
     if prev_actions.ndim != 2:

src/lerobot/scripts/lerobot_eval.py

@@ -82,9 +82,9 @@ from lerobot.envs import (
     make_env_pre_post_processors,
     preprocess_observation,
 )
+from lerobot.lerobot_types import PolicyAction
 from lerobot.policies import PreTrainedPolicy, make_policy, make_pre_post_processors
 from lerobot.processor import PolicyProcessorPipeline
-from lerobot.types import PolicyAction
 from lerobot.utils.constants import ACTION, DONE, OBS_IMAGE, OBS_IMAGES, OBS_STR, REWARD
 from lerobot.utils.device_utils import get_safe_torch_device
 from lerobot.utils.import_utils import _peft_available, register_third_party_plugins, require_package

src/lerobot/scripts/lerobot_train.py

@@ -348,7 +348,6 @@ def train(cfg: TrainPipelineConfig, accelerator: "Accelerator | None" = None):
         preprocessor_overrides = {
             "device_processor": {"device": device.type},
             "normalizer_processor": {
-                "stats": dataset.meta.stats,
                 "features": {**policy.config.input_features, **policy.config.output_features},
                 "norm_map": policy.config.normalization_mapping,
             },
@@ -356,11 +355,17 @@ def train(cfg: TrainPipelineConfig, accelerator: "Accelerator | None" = None):
         }
         postprocessor_overrides = {
             "unnormalizer_processor": {
-                "stats": dataset.meta.stats,
                 "features": policy.config.output_features,
                 "norm_map": policy.config.normalization_mapping,
             },
         }
+        # On resume, the checkpoint's saved processor stats are authoritative: they may have
+        # been adapted by the policy (e.g. EVO1 pads state/action stats to max_state_dim),
+        # and force-feeding raw dataset stats over them crashes normalization (#4006).
+        # This mirrors the `dataset_stats` kwarg above, which is also skipped on resume.
+        if not cfg.resume:
+            preprocessor_overrides["normalizer_processor"]["stats"] = dataset.meta.stats
+            postprocessor_overrides["unnormalizer_processor"]["stats"] = dataset.meta.stats
         if getattr(active_cfg, "use_relative_actions", False):
             preprocessor_overrides["relative_actions_processor"] = {
                 "enabled": True,