Merge remote-tracking branch 'origin/main' into codex/episode-video-streaming-byte-cache

# Conflicts:
#	src/lerobot/scripts/lerobot_train.py

AGENT_GUIDE.md

@@ -61,20 +61,16 @@ Full details in [`docs/source/so101.mdx`](./docs/source/so101.mdx) and [`docs/so
 **4.1 Install**
 
 ```bash
-# uv (recommended — see AGENTS.md and CLAUDE.md)
-uv sync --locked --extra feetech          # SO-100/SO-101 motor stack
-# uv sync --locked --extra all            # everything
-# uv sync --locked --extra smolvla        # add SmolVLA deps
-
-# pip (alternative, e.g. when not working from source)
-# pip install 'lerobot[feetech]'
-# pip install 'lerobot[all]'
-# pip install 'lerobot[smolvla]'
-
+pip install 'lerobot[feetech]'              # SO-100/SO-101 motor stack
+# pip install 'lerobot[all]'                # everything
+# pip install 'lerobot[aloha,pusht]'        # specific features
+# pip install 'lerobot[smolvla]'            # add SmolVLA deps
 git lfs install && git lfs pull
-hf auth login                             # required to push datasets/policies
+hf auth login                               # required to push datasets/policies
 ```
 
+Contributors can alternatively use `uv sync --locked --extra feetech` (see `AGENTS.md`).
+
 **4.2 Find USB ports** — run once per arm, unplug when prompted.
 
 ```bash

docker/Dockerfile.internal

@@ -68,16 +68,17 @@ ENV HOME=/home/user_lerobot \
 # issues with MuJoCo and OpenGL drivers.
 RUN uv venv --python python${PYTHON_VERSION}
 
-# Install third-party dependencies separately for layer caching
+# Install Python dependencies for caching
 COPY --chown=user_lerobot:user_lerobot setup.py pyproject.toml uv.lock README.md MANIFEST.in ./
-RUN uv sync --locked --extra all --no-install-project --no-cache
+COPY --chown=user_lerobot:user_lerobot src/ src/
+
+RUN uv sync --locked --extra all --no-cache
 
 RUN chmod +x /lerobot/.venv/lib/python${PYTHON_VERSION}/site-packages/triton/backends/nvidia/bin/ptxas
 
-# Copy the application source code and install the local project
+# Copy the rest of the application source code
 # Make sure to have the git-LFS files for testing
 COPY --chown=user_lerobot:user_lerobot . .
-RUN uv sync --locked --extra all --no-cache
 
 # Set the default command
 CMD ["/bin/bash"]

docker/Dockerfile.user

@@ -60,14 +60,15 @@ ENV HOME=/home/user_lerobot \
 # run other Python projects in the same container without dependency conflicts.
 RUN uv venv
 
-# Install third-party dependencies separately for layer caching
+# Install Python dependencies for caching
 COPY --chown=user_lerobot:user_lerobot setup.py pyproject.toml uv.lock README.md MANIFEST.in ./
-RUN uv sync --locked --extra all --no-install-project --no-cache
+COPY --chown=user_lerobot:user_lerobot src/ src/
 
-# Copy the application code and install the local project
+RUN uv sync --locked --extra all --no-cache
+
+# Copy the rest of the application code
 # Make sure to have the git-LFS files for testing
 COPY --chown=user_lerobot:user_lerobot . .
-RUN uv sync --locked --extra all --no-cache
 
 # Set the default command
 CMD ["/bin/bash"]

docs/source/_toctree.yml

@@ -37,6 +37,8 @@
 - sections:
   - local: lerobot-dataset-v3
     title: Using LeRobotDataset
+  - local: training_dataset_streaming
+    title: Training Dataset Streaming
   - local: porting_datasets_v3
     title: Porting Large Datasets
   - local: using_dataset_tools

docs/source/backwardcomp.mdx

@@ -58,7 +58,7 @@ final_action = postprocessor(action)
 
 ## Hardware API redesign
 
-PR [#777](https://github.com/huggingface/lerobot/pull/777) improves the LeRobot calibration but is **not backward-compatible**. Below is an overview of what changed and how you can continue to work with datasets created before this pull request.
+PR [#777](https://github.com/huggingface/lerobot/pull/777) improves the LeRobot calibration but is **not backward-compatible**. Below is a overview of what changed and how you can continue to work with datasets created before this pull request.
 
 ### What changed?
 
@@ -129,8 +129,8 @@ python examples/backward_compatibility/replay.py \
 
 Policies output actions in the same format as the datasets (`torch.Tensors`). Therefore, the same transformations should be applied.
 
-To find these transformations, we recommend first replaying an episode of the dataset your policy was trained on using the section above.
-Then, add these same transformations to your inference script (shown here in the `record.py` script):
+To find these transformations, we recommend to first try and and replay an episode of the dataset your policy was trained on using the section above.
+Then, add these same transformations on your inference script (shown here in the `record.py` script):
 
 ```diff
 action_values = predict_action(

docs/source/cameras.mdx

@@ -136,10 +136,6 @@ config = RealSenseCameraConfig(
     height=480,
     color_mode=ColorMode.RGB,
     use_depth=True,
-    # Optional fixed color controls. Omit them to leave the current sensor settings unchanged.
-    exposure=120,
-    gain=64,
-    white_balance=4600,
     rotation=Cv2Rotation.NO_ROTATION
 )
 
@@ -158,15 +154,6 @@ finally:
 ```
 <!-- prettier-ignore-end -->
 
-Manual color controls disable the corresponding automatic exposure or white-balance mode. Their
-supported ranges vary by camera model; an invalid value raises an error at connection time that
-includes the range reported by the sensor. Requesting an unsupported control also raises an error.
-Omitted controls leave the sensor's existing automatic or manual setting unchanged. These options
-require `use_rgb=True`.
-
-Manual color controls require a dedicated RGB module. Cameras without one, such as the RealSense
-D405, do not support them and raise an error at connection time.
-
 </hfoption>
 </hfoptions>
 

docs/source/env_processor.mdx

@@ -88,6 +88,20 @@ policy_preprocessor = NormalizerProcessorStep(stats=dataset_stats)
 
 The same policy can work with different environment processors, and the same environment processor can work with different policies:
 
+````python
+# Use SmolVLA policy with LIBERO environment
+# Use SmolVLA policy with LIBERO environment
+libero_preprocessor, libero_postprocessor = make_env_pre_post_processors(
+    env_cfg=libero_cfg,
+    policy_cfg=smolvla_cfg,
+)
+smolvla_preprocessor, smolvla_postprocessor = make_pre_post_processors(smolvla_cfg)
+# Or use ACT policy with the same LIBERO environment
+libero_preprocessor, libero_postprocessor = make_env_pre_post_processors(
+    env_cfg=libero_cfg,
+    policy_cfg=act_cfg,
+)
+act_preprocessor, act_postprocessor = make_pre_post_processors(act_cfg)
 ```python
 # Use SmolVLA policy with LIBERO environment
 libero_preprocessor, libero_postprocessor = make_env_pre_post_processors(
@@ -102,7 +116,6 @@ libero_preprocessor, libero_postprocessor = make_env_pre_post_processors(
     policy_cfg=act_cfg,
 )
 act_preprocessor, act_postprocessor = make_pre_post_processors(act_cfg)
-```
 
 ### 3. **Easier Experimentation**
 
@@ -132,7 +145,7 @@ class LiberoVelocityProcessorStep(ObservationProcessorStep):
         state = torch.cat([eef_pos, eef_axisangle, eef_vel,
                           gripper_pos, gripper_vel], dim=-1)  # 14D
         return state
-```
+````
 
 ### 4. **Cleaner Environment Code**
 

docs/source/feetech.mdx

@@ -40,10 +40,10 @@ This tutorial guides you through updating the firmware of Feetech motors using t
 For each motor you want to update:
 
 1. **Select the motor** from the list by clicking on it
-2. **Click the Upgrade tab**:
-3. **Click the Online button**:
-   - If a potential firmware update is found, it will be displayed in the box
-4. **Click the Upgrade button**:
+2. **Click on Upgrade tab**:
+3. **Click on Online button**:
+   - If an potential firmware update is found, it will be displayed in the box
+4. **Click on Upgrade button**:
    - The update progress will be displayed
 
 ## Step 6: Verify Update

docs/source/hil_data_collection.mdx

@@ -59,7 +59,6 @@ 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/hope_jr.mdx

@@ -211,7 +211,7 @@ Record, Replay and Train with Hope-JR is still experimental.
 
 ### Record
 
-This step records the dataset, which can be seen as an example [here](https://huggingface.co/datasets/nepyope/hand_record_test_with_video_data).
+This step records the dataset, which can be seen as an example [here](https://huggingface.co/datasets/nepyope/hand_record_test_with_video_data/settings).
 
 ```bash
 lerobot-record \

docs/source/integrate_hardware.mdx

@@ -18,7 +18,7 @@ If you're using Feetech or Dynamixel motors, LeRobot provides built-in bus inter
 - [`DynamixelMotorsBus`](https://github.com/huggingface/lerobot/blob/main/src/lerobot/motors/dynamixel/dynamixel.py) – for controlling Dynamixel servos
 
 Please refer to the [`MotorsBus`](https://github.com/huggingface/lerobot/blob/main/src/lerobot/motors/motors_bus.py) abstract class to learn about its API.
-For a good example of how it can be used, you can have a look at our own [SO101 follower implementation](https://github.com/huggingface/lerobot/blob/main/src/lerobot/robots/so_follower/so_follower.py)
+For a good example of how it can be used, you can have a look at our own [SO101 follower implementation](https://github.com/huggingface/lerobot/blob/main/src/lerobot/robots/so_follower/so101_follower/so101_follower.py)
 
 Use these if compatible. Otherwise, you'll need to find or write a Python interface (not covered in this tutorial):
 

docs/source/lekiwi.mdx

@@ -51,7 +51,7 @@ In addition to these instructions, you need to install the Feetech SDK & ZeroMQ
 pip install -e ".[lekiwi]"
 ```
 
-Great 🤗! You are now done installing LeRobot, and we can begin assembling the SO100/SO101 arms and the mobile base 🤖.
+Great :hugs:! You are now done installing LeRobot, and we can begin assembling the SO100/SO101 arms and the mobile base :robot:.
 Every time you now want to use LeRobot, you can go to the `~/lerobot` folder where we installed LeRobot and run one of the commands.
 
 # Step-by-Step Assembly Instructions

docs/source/lerobot-dataset-v3.mdx

@@ -131,15 +131,54 @@ for batch in data_loader:
     # model.forward(batch)
 ```
 
-## Stream a dataset (no downloads)
+## Stream a dataset during training
 
-Use `StreamingLeRobotDataset` to iterate directly from the Hub without local copies. This allows to stream large datasets without the need to downloading them onto disk or loading them onto memory, and is a key feature of the new dataset format.
+Enable training-time streaming with the public `--dataset.streaming=true` flag:
+
+```bash
+lerobot-train \
+  --dataset.repo_id=yaak-ai/L2D-v3 \
+  --dataset.streaming=true \
+  --policy.type=act \
+  --output_dir=outputs/train/act_streaming
+```
+
+This is separate from `--dataset.streaming_encoding=true`, which controls video encoding while
+recording. Training-time streaming leaves the map-style `LeRobotDataset` path unchanged.
+
+`StreamingLeRobotDataset` assigns complete episodes disjointly across distributed ranks and
+DataLoader workers, reads only the selected episode rows from Parquet, and keeps a bounded pool of
+episode video bytes. Every selected frame is visited exactly once per streaming epoch.
+
+On first use, LeRobot looks for a revision-matched MP4 index sidecar. If none is published with the
+dataset, it builds one in the revision-keyed local LeRobot cache under a process lock and installs it
+atomically. Training never uploads this sidecar. Dataset maintainers can build and publish one
+explicitly with `scripts/build_mp4_sidecar.py --push`.
+
+The default memory cap is 8 GiB per DataLoader worker. It can be adjusted along with episode mixing
+and prefetch:
+
+```bash
+lerobot-train \
+  --dataset.repo_id=yaak-ai/L2D-v3 \
+  --dataset.streaming=true \
+  --dataset.streaming_byte_budget_gb=4 \
+  --dataset.streaming_episode_pool_size=16 \
+  --dataset.streaming_prefetch_episodes=4 \
+  --policy.type=act \
+  --output_dir=outputs/train/act_streaming
+```
+
+Use `--dataset.streaming_data_root=hf://buckets/OWNER/BUCKET/PREFIX` when metadata lives in a
+dataset repository but Parquet and MP4 data are mirrored in an HF Bucket.
+
+The Python API uses the same implementation:
 
 ```python
 from lerobot.datasets import StreamingLeRobotDataset
 
 repo_id = "yaak-ai/L2D-v3"
-dataset = StreamingLeRobotDataset(repo_id)  # streams directly from the Hub
+dataset = StreamingLeRobotDataset(repo_id)
 ```
 
 <div style="display:flex; justify-content:center; gap:12px; flex-wrap:wrap;">

docs/source/pi0fast.mdx

@@ -174,7 +174,7 @@ The model takes images, text instructions, and robot state as input, and outputs
 
 ## Reproducing π₀Fast results
 
-We reproduce the results of π₀Fast on the LIBERO benchmark using the LeRobot implementation. We take the LeRobot PiFast base model [lerobot/pi0fast-base](https://huggingface.co/lerobot/pi0fast-base) and finetune for an additional 40k steps in bfloat16, with batch size of 256 on 8 H100 GPUs using the [HuggingFace LIBERO dataset](https://huggingface.co/datasets/HuggingFaceVLA/libero).
+We reproduce the results of π₀Fast on the LIBERO benchmark using the LeRobot implementation. We take the LeRobot PiFast base model [lerobot/pi0fast-base](https://huggingface.co/lerobot/pi0fast-base) and finetune for an additional 40kk steps in bfloat16, with batch size of 256 on 8 H100 GPUs using the [HuggingFace LIBERO dataset](https://huggingface.co/datasets/HuggingFaceVLA/libero).
 
 The finetuned model can be found here:
 

docs/source/processors_robots_teleop.mdx

@@ -22,7 +22,7 @@ With processors, you choose the learning features you want to use for your polic
 ## Three pipelines
 
 We often compose three pipelines. Depending on your setup, some can be empty if action and observation spaces already match.
-Each of these pipelines handles different conversions between different action and observation spaces. Below is a quick explanation of each pipeline.
+Each of these pipelines handle different conversions between different action and observation spaces. Below is a quick explanation of each pipeline.
 
 1. Pipeline 1: Teleop action space → dataset action space (phone pose → EE targets)
 2. Pipeline 2: Dataset action space → robot command space (EE targets → joints)
@@ -74,15 +74,15 @@ In the phone to SO-100 follower examples we use the following adapters:
 - `robot_action_to_transition`: transforms the teleop action dict to a pipeline transition.
 - `transition_to_robot_action`: transforms the pipeline transition to a robot action dict.
 - `observation_to_transition`: transforms the robot observation dict to a pipeline transition.
-- `transition_to_observation`: transforms the pipeline transition to an observation dict.
+- `transition_to_observation`: transforms the pipeline transition to a observation dict.
 
-Check out [src/lerobot/processor/converters.py](https://github.com/huggingface/lerobot/blob/main/src/lerobot/processor/converters.py) for more details.
+Checkout [src/lerobot/processor/converters.py](https://github.com/huggingface/lerobot/blob/main/src/lerobot/processor/converters.py) for more details.
 
 ## Dataset feature contracts
 
 Dataset features are determined by the keys saved in the dataset. Each step can declare what features it modifies in a contract called `transform_features(...)`. Once you build a processor, the processor can then aggregate all of these features with `aggregate_pipeline_dataset_features()` and merge multiple feature dicts with `combine_feature_dicts(...)`.
 
-Below is an example of how we declare features with the `transform_features` method in the phone to SO-100 follower examples:
+Below is and example of how we declare features with the `transform_features` method in the phone to SO-100 follower examples:
 
 ```python
     def transform_features(

docs/source/robocasa.mdx

@@ -82,8 +82,6 @@ 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/rtc.mdx

@@ -57,7 +57,7 @@ policy_cfg.rtc_config = RTCConfig(
 policy = PI0Policy.from_pretrained("lerobot/pi0_base", policy_cfg=policy_cfg, device="cuda")
 
 # Now use predict_action_chunk with RTC parameters
-inference_delay = 4  # How many steps of inference latency, this value should be calculated based on the inference latency of the policy
+inference_delay = 4  # How many steps of inference latency, this values should be calculated based on the inference latency of the policy
 
 # Initialize the action queue
 action_queue = ActionQueue(policy_cfg.rtc_config)
@@ -100,7 +100,7 @@ Typical values: 8-12 steps
 RTCConfig(execution_horizon=10)
 ```
 
-**`max_guidance_weight`**: How strongly to enforce consistency with the previous chunk. This is a hyperparameter that can be tuned to balance the smoothness of the transitions and the reactivity of the policy. For 10 steps flow matching (SmolVLA, Pi0, Pi0.5), a value of 10.0 is an optimal value.
+**`max_guidance_weight`**: How strongly to enforce consistency with the previous chunk. This is a hyperparameter that can be tuned to balance the smoothness of the transitions and the reactivity of the policy. For 10 steps flow matching (SmolVLA, Pi0, Pi0.5), a value of 10.0 is a optimal value.
 
 **`prefix_attention_schedule`**: How to weight consistency across the overlap region.
 

docs/source/smolvla.mdx

@@ -93,7 +93,7 @@ lerobot-train --help
 
 ## Evaluate the finetuned model and run it in real-time
 
-Similarly for when recording an episode, it is recommended that you are logged in to the HuggingFace Hub. You can follow the corresponding steps: [Record a dataset](./il_robots#record-a-dataset).
+Similarly for when recording an episode, it is recommended that you are logged in to the HuggingFace Hub. You can follow the corresponding steps: [Record a dataset](./il_robots).
 Once you are logged in, you can run inference in your setup by doing:
 
 ```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 the leader holder using 1 M2x6mm screw.
+- Attach the handle to motor 5 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.
 

docs/source/training_dataset_streaming.mdx

@@ -0,0 +1,121 @@
+# Training Dataset Streaming
+
+Training-time dataset streaming lets `lerobot-train` consume a LeRobotDataset v3 without first
+downloading its complete Parquet and video payload. Enable it through the existing public switch:
+
+```bash
+lerobot-train \
+  --dataset.repo_id=OWNER/DATASET \
+  --dataset.streaming=true \
+  --policy.type=act \
+  --output_dir=outputs/train/act_streaming
+```
+
+This feature is independent of `--dataset.streaming_encoding=true`. `streaming_encoding` controls
+how videos are written while recording; `dataset.streaming` controls how an existing dataset is read
+during training. Recording and rollout encoders are not used by this training path.
+
+## How an epoch is read
+
+Each distributed rank owns a deterministic, frame-balanced set of complete episodes. One logical
+exact-coverage pool per rank mixes those episodes while visiting every selected frame once per
+rank-local coverage epoch. Parquet columns and compressed MP4 byte ranges are prefetched from the
+same byte-aware admission frontier. Temporal history and future windows are resolved inside the
+complete episode, including the same boundary padding masks as map-style loading.
+
+When `--num_workers` is nonzero, training uses one dedicated DataLoader process per rank. Its
+bounded result queue holds decoded batches while the policy trains. The configured worker count is
+instead used as internal Parquet and byte-range fetch concurrency, so increasing it does not create
+independent samplers or multiply the cache budget.
+
+The default map-style `LeRobotDataset` behavior is unchanged when `--dataset.streaming=false`.
+
+## MP4 sidecars and the first run
+
+Video streaming uses a small MP4 index sidecar. Dataset initialization first checks the
+revision-keyed local cache, then looks for a valid published sidecar. If neither is available,
+LeRobot builds the sidecar locally while holding a process lock and installs it atomically. A
+failed or interrupted build does not replace the previous valid file.
+
+Training is read-only: it never uploads a sidecar or modifies the dataset repository. On a cluster
+with node-local caches, the first job may build once per node. A shared LeRobot cache avoids that
+duplication.
+
+Dataset maintainers can build a sidecar ahead of time:
+
+```bash
+uv run python scripts/build_mp4_sidecar.py \
+  --repo-id=OWNER/DATASET \
+  --revision=COMMIT_SHA \
+  --data-root=hf://datasets/OWNER/DATASET@COMMIT_SHA \
+  --output=/tmp/dataset-mp4-sidecar.npz
+```
+
+Publication is always explicit. Add `--push` only after validating the complete-dataset sidecar.
+Subset sidecars cannot be published.
+
+## Configuration
+
+The production defaults are:
+
+| Option                              |        Default | Meaning                                             |
+| ----------------------------------- | -------------: | --------------------------------------------------- |
+| `streaming_episode_pool_size`       |             32 | Maximum complete episodes mixed by each rank        |
+| `streaming_prefetch_episodes`       |              8 | Episodes fetched ahead of the active pool           |
+| `streaming_byte_budget_gb`          |              8 | Maximum synthesized MP4 bytes per rank              |
+| `streaming_decode_threads`          |              2 | Parallel sample assembly and video decode workers   |
+| `streaming_decoded_queue_size`      |              8 | Decoded samples buffered ahead, in planner order    |
+| `streaming_max_open_decoders`       | pool × cameras | Independent open-decoder LRU cap per rank           |
+| `streaming_native_http_connections` |          unset | Native HTTP connection cap per rank                 |
+| `streaming_native_http_subranges`   |              1 | Concurrent subranges per native HTTP range read     |
+| `streaming_data_root`               |          unset | Optional local, Hub, bucket, or fsspec payload root |
+
+The active episode set is capped by both episode count and the exact synthesized mini-MP4 sizes
+computed from the sidecar. An episode larger than the complete rank budget fails before training
+fetches its payload. The cache, decoder LRU, and decoded-batch queue remain independently bounded.
+Start with a smaller pool or budget on memory-constrained hosts:
+
+```bash
+lerobot-train \
+  --dataset.repo_id=OWNER/DATASET \
+  --dataset.streaming=true \
+  --dataset.streaming_episode_pool_size=16 \
+  --dataset.streaming_prefetch_episodes=4 \
+  --dataset.streaming_byte_budget_gb=4 \
+  --dataset.streaming_decode_threads=2 \
+  --dataset.streaming_decoded_queue_size=8 \
+  --num_workers=4 \
+  --policy.type=act \
+  --output_dir=outputs/train/act_streaming
+```
+
+If metadata remains in a dataset repository while payload files are mirrored elsewhere, set
+`--dataset.streaming_data_root`. Supported values include local paths, revision-qualified
+`hf://datasets/...` roots, `hf://buckets/...` roots, and fsspec URLs.
+
+## Resume and shuffle migration
+
+The earlier streaming reader used a bounded row shuffle buffer. The episode reader instead has
+deterministic exact-coverage ordering derived from the seed and epoch. Checkpoint resume restores the
+per-rank sample offset using the checkpoint batch size. Changing distributed world size or
+batch size changes ownership or batch boundaries. For sample-exact comparisons, resume with the
+same world size and batch size. Keep the same internal fetch concurrency when comparing performance.
+
+Streaming checkpoints created by the earlier multi-worker sampler record a different ownership
+topology and are rejected for sample-exact resume. Start a new run from the saved policy weights
+rather than claiming that its dataset stream resumes exactly.
+
+## Troubleshooting
+
+- **The first batch takes a long time:** check logs for a sidecar build. Reuse a shared cache or
+  publish a validated complete sidecar explicitly.
+- **A sidecar lock times out:** another process may still be indexing the same revision. Confirm it
+  is healthy before removing a stale lock.
+- **A rank owns no data:** reduce the number of ranks so every rank owns at least one selected
+  episode.
+- **The byte budget is exceeded:** lower the episode pool, increase the per-rank byte budget, or
+  use an explicitly prepared payload layout with smaller episode ranges.
+- **Remote reads cannot authenticate:** verify the normal Hugging Face token or fsspec credentials
+  are available in every worker environment. Credentials are never embedded in the sidecar.
+- **Refill stalls are high:** compare p95/p99 batch wait, reduce network contention, raise prefetch
+  gradually, and verify that the dataset sidecar matches the exact revision.

docs/source/using_dataset_tools.mdx

@@ -50,11 +50,11 @@ lerobot-edit-dataset \
 Divide a dataset into multiple subsets.
 
 ```bash
-# Split by fractions (e.g. 60% train, 20% val, 20% test)
+# Split by fractions (e.g. 80% train, 20% test, 20% val)
 lerobot-edit-dataset \
     --repo_id lerobot/pusht \
     --operation.type split \
-    --operation.splits '{"train": 0.6, "val": 0.2, "test": 0.2}'
+    --operation.splits '{"train": 0.8, "test": 0.2, "val": 0.2}'
 
 # Split by specific episode indices
 lerobot-edit-dataset \

examples/isaac_teleop_to_so101/common.py

@@ -44,7 +44,6 @@ 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,
@@ -57,6 +56,7 @@ 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.lerobot_types import RobotAction
+from 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.lerobot_types import RobotAction
+from 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

@@ -21,7 +21,6 @@ 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
@@ -39,6 +38,7 @@ 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

@@ -16,7 +16,6 @@
 
 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,
@@ -37,6 +36,7 @@ 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

@@ -17,7 +17,6 @@
 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,
@@ -28,6 +27,7 @@ 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

@@ -27,7 +27,6 @@ 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,
@@ -44,6 +43,7 @@ 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

@@ -15,7 +15,6 @@
 
 import time
 
-from lerobot.lerobot_types import RobotAction, RobotObservation
 from lerobot.model.kinematics import RobotKinematics
 from lerobot.processor import (
     RobotProcessorPipeline,
@@ -32,6 +31,7 @@ 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

@@ -21,7 +21,6 @@ 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
@@ -39,6 +38,7 @@ 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

@@ -17,7 +17,6 @@
 
 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,
@@ -34,6 +33,7 @@ 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

@@ -18,7 +18,6 @@
 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,
@@ -29,6 +28,7 @@ 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

@@ -25,7 +25,6 @@ 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,
@@ -42,6 +41,7 @@ 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

@@ -16,7 +16,6 @@
 
 import time
 
-from lerobot.lerobot_types import RobotAction, RobotObservation
 from lerobot.model.kinematics import RobotKinematics
 from lerobot.processor import (
     RobotProcessorPipeline,
@@ -31,6 +30,7 @@ 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
 

examples/training/train_with_streaming.py

@@ -12,8 +12,12 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-"""This script demonstrates how to train a Diffusion Policy on the PushT environment,
-using a dataset processed in streaming mode."""
+"""Train directly from episode-scoped Parquet and MP4 streams.
+
+For normal training, prefer ``lerobot-train --dataset.streaming=true`` so distributed sharding,
+checkpoint resume, and device placement are configured by the training pipeline. This lower-level
+example shows the underlying Python API.
+"""
 
 from pathlib import Path
 
@@ -64,18 +68,28 @@ def main():
         ACTION: [t / dataset_metadata.fps for t in range(cfg.n_action_steps)],
     }
 
-    # Instantiating the training dataset in streaming mode allows to not consume up memory as the data is fetched
-    # iteratively rather than being load into memory all at once. Retrieved frames are shuffled across epochs
-    dataset = StreamingLeRobotDataset(dataset_id, delta_timestamps=delta_timestamps, tolerance_s=1e-3)
+    # The first run resolves or locally builds a revision-safe MP4 index sidecar. It is never
+    # uploaded implicitly. Episode rows and video byte ranges are then prefetched together.
+    dataset = StreamingLeRobotDataset(
+        dataset_id,
+        delta_timestamps=delta_timestamps,
+        tolerance_s=1e-3,
+        episode_pool_size=16,
+        prefetch_episodes=4,
+        byte_budget_gb=4,
+        repeat=True,
+    )
 
     optimizer = torch.optim.Adam(policy.parameters(), lr=1e-4)
     dataloader = torch.utils.data.DataLoader(
         dataset,
-        num_workers=4,
+        # One worker owns the rank-level pool. Internal fetch concurrency is configured through
+        # StreamingLeRobotDataset.max_num_shards (the lerobot-train CLI derives it from num_workers).
+        num_workers=1,
         batch_size=16,
         pin_memory=device.type != "cpu",
-        drop_last=True,
-        prefetch_factor=2,  # loads batches with multiprocessing while policy trains
+        prefetch_factor=2,  # bounded decoded-batch queue while the policy trains
+        persistent_workers=True,
     )
 
     # Run training loop.

pyproject.toml

@@ -67,8 +67,11 @@ dependencies = [
     "einops>=0.8.0,<0.9.0",
 
     # Config & Hub
-    "draccus>=0.11.6,<0.12.0",
+    "draccus==0.10.0", # TODO: Relax version constraint
     "huggingface-hub>=1.0.0,<2.0.0",
+    "filelock>=3.12.0,<4.0.0",
+    "fsspec>=2023.5.0,<2027.0.0",
+    "httpx>=0.27.0,<1.0.0",
     "requests>=2.32.0,<3.0.0",
 
     # Environments
@@ -436,6 +439,7 @@ exclude_dirs = [
 skips = ["B101", "B311", "B404", "B603", "B615"]
 
 [tool.typos]
+default.extend-words = { trak = "trak" }
 default.extend-ignore-re = [
     "(?Rm)^.*(#|//)\\s*spellchecker:disable-line$",                      # spellchecker:disable-line
     "(?s)(#|//)\\s*spellchecker:off.*?\\n\\s*(#|//)\\s*spellchecker:on", # spellchecker:<on|off>
@@ -494,19 +498,6 @@ ignore_errors = true
 module = "lerobot.envs.*"
 ignore_errors = false
 
-[[tool.mypy.overrides]]
-module = "lerobot.annotations.*"
-ignore_errors = false
-disallow_untyped_defs = true
-disallow_incomplete_defs = true
-check_untyped_defs = true
-
-[[tool.mypy.overrides]]
-module = "lerobot.transforms.*"
-ignore_errors = false
-disallow_untyped_defs = true
-disallow_incomplete_defs = true
-check_untyped_defs = true
 
 # [[tool.mypy.overrides]]
 # module = "lerobot.utils.*"

scripts/build_mp4_sidecar.py

@@ -0,0 +1,95 @@
+#!/usr/bin/env python
+
+# Copyright 2026 The HuggingFace Inc. team. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+
+from __future__ import annotations
+
+import argparse
+import time
+from pathlib import Path
+
+import fsspec
+
+from lerobot.datasets.dataset_metadata import LeRobotDatasetMetadata
+from lerobot.datasets.streaming_sidecar import (
+    build_mp4_sidecar,
+    make_sidecar_spec,
+    published_sidecar_url,
+    range_backend_for_root,
+)
+from lerobot.streaming.sidecar import SidecarSpec
+
+
+def parse_args() -> argparse.Namespace:
+    parser = argparse.ArgumentParser(description="Build a reusable MP4 byte-index sidecar for streaming.")
+    parser.add_argument("--repo-id", required=True)
+    parser.add_argument("--revision", default=None)
+    parser.add_argument("--data-root", required=True)
+    parser.add_argument("--output", required=True)
+    parser.add_argument("--episodes", type=int, default=None)
+    parser.add_argument("--workers", type=int, default=8)
+    parser.add_argument("--range-backend", choices=("fsspec", "native-http"), default=None)
+    parser.add_argument("--max-probe-mb", type=int, default=64)
+    parser.add_argument("--push", action="store_true", help="Explicitly publish the sidecar to data_root.")
+    return parser.parse_args()
+
+
+def push_sidecar(local_path: str, spec: SidecarSpec) -> list[str]:
+    if not spec.data_root.startswith("hf://"):
+        raise ValueError("--push currently supports only hf:// data roots")
+
+    fs = fsspec.filesystem("hf")
+    remote = published_sidecar_url(spec)
+    fs.put(str(Path(local_path)), remote)
+    return [remote]
+
+
+def main() -> None:
+    args = parse_args()
+
+    meta = LeRobotDatasetMetadata(args.repo_id, revision=args.revision)
+    meta.ensure_readable()
+    total = (
+        int(meta.total_episodes) if args.episodes is None else min(args.episodes, int(meta.total_episodes))
+    )
+    spec = make_sidecar_spec(meta, args.data_root)
+    if total != int(meta.total_episodes):
+        selected_paths = {
+            str(meta.get_video_file_path(ep_idx, key)) for ep_idx in range(total) for key in meta.video_keys
+        }
+        spec = SidecarSpec(
+            repo_id=spec.repo_id,
+            revision=spec.revision,
+            data_root=spec.data_root,
+            source_files=tuple(item for item in spec.source_files if item[0] in selected_paths),
+        )
+
+    start = time.perf_counter()
+    build_mp4_sidecar(
+        args.output,
+        spec,
+        range_backend=args.range_backend or range_backend_for_root(args.data_root),
+        workers=args.workers,
+        max_probe_bytes=args.max_probe_mb * 1024 * 1024,
+    )
+    elapsed = time.perf_counter() - start
+    print(f"wrote {args.output}")
+    print(f"episodes={total} files={len(spec.source_files)} elapsed_s={elapsed:.2f}")
+    if args.push:
+        if total != int(meta.total_episodes):
+            raise ValueError("Only a complete dataset sidecar can be published")
+        pushed = push_sidecar(args.output, spec)
+        for remote in pushed:
+            print(f"pushed {remote}")
+    else:
+        print("push_skipped: pass --push for explicit publication")
+
+
+if __name__ == "__main__":
+    main()

src/lerobot/async_inference/policy_server.py

@@ -38,7 +38,6 @@ 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 (
@@ -46,6 +45,7 @@ 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/opencv/camera_opencv.py

@@ -120,22 +120,14 @@ class OpenCVCamera(Camera):
         self.rotation: int | None = get_cv2_rotation(config.rotation)
         self.backend: int = config.backend
 
-        self.capture_width: int | None = None
-        self.capture_height: int | None = None
-        self._reset_connection_settings()
+        if self.height and self.width:
+            self.capture_width, self.capture_height = self.width, self.height
+            if self.rotation in [cv2.ROTATE_90_CLOCKWISE, cv2.ROTATE_90_COUNTERCLOCKWISE]:
+                self.capture_width, self.capture_height = self.height, self.width
 
     def __str__(self) -> str:
         return f"{self.__class__.__name__}({self.index_or_path})"
 
-    def _reset_connection_settings(self) -> None:
-        """Restore settings that may have been auto-detected during a failed connection."""
-        self.fps = self.config.fps
-        self.width = self.config.width
-        self.height = self.config.height
-        self.capture_width, self.capture_height = self.width, self.height
-        if self.rotation in [cv2.ROTATE_90_CLOCKWISE, cv2.ROTATE_90_COUNTERCLOCKWISE]:
-            self.capture_width, self.capture_height = self.height, self.width
-
     @property
     def is_connected(self) -> bool:
         """Checks if the camera is currently connected and opened."""
@@ -172,25 +164,17 @@ class OpenCVCamera(Camera):
                 f"Failed to open {self}.Run `lerobot-find-cameras opencv` to find available cameras."
             )
 
-        try:
-            self._configure_capture_settings()
-            self._start_read_thread()
+        self._configure_capture_settings()
+        self._start_read_thread()
 
-            if warmup and self.warmup_s > 0:
-                start_time = time.time()
-                while time.time() - start_time < self.warmup_s:
-                    self.async_read(timeout_ms=self.warmup_s * 1000)
-                    time.sleep(0.1)
-                with self.frame_lock:
-                    if self.latest_frame is None:
-                        raise ConnectionError(f"{self} failed to capture frames during warmup.")
-        except BaseException:
-            try:
-                self._cleanup_resources()
-            except Exception:
-                logger.exception(f"Failed to fully clean up {self} after connect() failed.")
-            self._reset_connection_settings()
-            raise
+        if warmup and self.warmup_s > 0:
+            start_time = time.time()
+            while time.time() - start_time < self.warmup_s:
+                self.async_read(timeout_ms=self.warmup_s * 1000)
+                time.sleep(0.1)
+            with self.frame_lock:
+                if self.latest_frame is None:
+                    raise ConnectionError(f"{self} failed to capture frames during warmup.")
 
         logger.info(f"{self} connected.")
 
@@ -328,36 +312,32 @@ class OpenCVCamera(Camera):
 
         for target in targets_to_scan:
             camera = cv2.VideoCapture(target)
-            try:
-                if camera.isOpened():
-                    default_width = int(camera.get(cv2.CAP_PROP_FRAME_WIDTH))
-                    default_height = int(camera.get(cv2.CAP_PROP_FRAME_HEIGHT))
-                    default_fps = camera.get(cv2.CAP_PROP_FPS)
-                    default_format = camera.get(cv2.CAP_PROP_FORMAT)
+            if camera.isOpened():
+                default_width = int(camera.get(cv2.CAP_PROP_FRAME_WIDTH))
+                default_height = int(camera.get(cv2.CAP_PROP_FRAME_HEIGHT))
+                default_fps = camera.get(cv2.CAP_PROP_FPS)
+                default_format = camera.get(cv2.CAP_PROP_FORMAT)
 
-                    # Get FOURCC code and convert to string
-                    default_fourcc_code = camera.get(cv2.CAP_PROP_FOURCC)
-                    default_fourcc_code_int = int(default_fourcc_code)
-                    default_fourcc = "".join(
-                        [chr((default_fourcc_code_int >> 8 * i) & 0xFF) for i in range(4)]
-                    )
+                # Get FOURCC code and convert to string
+                default_fourcc_code = camera.get(cv2.CAP_PROP_FOURCC)
+                default_fourcc_code_int = int(default_fourcc_code)
+                default_fourcc = "".join([chr((default_fourcc_code_int >> 8 * i) & 0xFF) for i in range(4)])
 
-                    camera_info = {
-                        "name": f"OpenCV Camera @ {target}",
-                        "type": "OpenCV",
-                        "id": target,
-                        "backend_api": camera.getBackendName(),
-                        "default_stream_profile": {
-                            "format": default_format,
-                            "fourcc": default_fourcc,
-                            "width": default_width,
-                            "height": default_height,
-                            "fps": default_fps,
-                        },
-                    }
+                camera_info = {
+                    "name": f"OpenCV Camera @ {target}",
+                    "type": "OpenCV",
+                    "id": target,
+                    "backend_api": camera.getBackendName(),
+                    "default_stream_profile": {
+                        "format": default_format,
+                        "fourcc": default_fourcc,
+                        "width": default_width,
+                        "height": default_height,
+                        "fps": default_fps,
+                    },
+                }
 
-                    found_cameras_info.append(camera_info)
-            finally:
+                found_cameras_info.append(camera_info)
                 camera.release()
 
         return found_cameras_info
@@ -516,26 +496,6 @@ class OpenCVCamera(Camera):
             self.latest_timestamp = None
             self.new_frame_event.clear()
 
-    def _cleanup_resources(self) -> None:
-        """Stop background reads and release the capture, including after partial setup."""
-        read_thread = self.thread
-        videocapture = self.videocapture
-
-        try:
-            self._stop_read_thread()
-        finally:
-            self.videocapture = None
-            try:
-                if videocapture is not None:
-                    videocapture.release()
-            finally:
-                # Releasing the device may unblock a hardware read that outlived
-                # the first bounded join in _stop_read_thread().
-                if read_thread is not None and read_thread.is_alive():
-                    read_thread.join(timeout=2.0)
-                    if read_thread.is_alive():  # pragma: no cover
-                        logger.warning(f"{self} read thread remained alive after releasing the capture.")
-
     @check_if_not_connected
     def async_read(self, timeout_ms: float = 200) -> NDArray[Any]:
         """
@@ -626,6 +586,16 @@ class OpenCVCamera(Camera):
         if not self.is_connected and self.thread is None:
             raise DeviceNotConnectedError(f"{self} not connected.")
 
-        self._cleanup_resources()
+        if self.thread is not None:
+            self._stop_read_thread()
+
+        if self.videocapture is not None:
+            self.videocapture.release()
+            self.videocapture = None
+
+        with self.frame_lock:
+            self.latest_frame = None
+            self.latest_timestamp = None
+            self.new_frame_event.clear()
 
         logger.info(f"{self} disconnected.")

src/lerobot/cameras/realsense/camera_realsense.py

@@ -121,9 +121,6 @@ class RealSenseCamera(Camera):
 
         self.config = config
 
-        self.width: int | None = config.width
-        self.height: int | None = config.height
-
         if config.serial_number_or_name.isdigit():
             self.serial_number = config.serial_number_or_name
         else:
@@ -134,9 +131,6 @@ class RealSenseCamera(Camera):
         self.use_rgb = config.use_rgb
         self.use_depth = config.use_depth
         self.warmup_s = config.warmup_s
-        self.exposure: int | None = config.exposure
-        self.gain: int | None = config.gain
-        self.white_balance: int | None = config.white_balance
 
         self.rs_pipeline: rs.pipeline | None = None
         self.rs_profile: rs.pipeline_profile | None = None
@@ -151,23 +145,14 @@ class RealSenseCamera(Camera):
 
         self.rotation: int | None = get_cv2_rotation(config.rotation)
 
-        self.capture_width: int | None = None
-        self.capture_height: int | None = None
-        self._reset_connection_settings()
+        if self.height and self.width:
+            self.capture_width, self.capture_height = self.width, self.height
+            if self.rotation in [cv2.ROTATE_90_CLOCKWISE, cv2.ROTATE_90_COUNTERCLOCKWISE]:
+                self.capture_width, self.capture_height = self.height, self.width
 
     def __str__(self) -> str:
         return f"{self.__class__.__name__}({self.serial_number})"
 
-    def _reset_connection_settings(self) -> None:
-        """Restore settings that may have been auto-detected during a failed connection."""
-        self.fps = self.config.fps
-        self.width = self.config.width
-        self.height = self.config.height
-        self.warmup_s = self.config.warmup_s
-        self.capture_width, self.capture_height = self.width, self.height
-        if self.rotation in [cv2.ROTATE_90_CLOCKWISE, cv2.ROTATE_90_COUNTERCLOCKWISE]:
-            self.capture_width, self.capture_height = self.height, self.width
-
     @property
     def is_connected(self) -> bool:
         """Checks if the camera pipeline is started and streams are active."""
@@ -187,8 +172,7 @@ class RealSenseCamera(Camera):
 
         Raises:
             DeviceAlreadyConnectedError: If the camera is already connected.
-            ValueError: If the configuration is invalid, a requested sensor option is unsupported,
-                or a requested sensor value is invalid.
+            ValueError: If the configuration is invalid (e.g., missing serial/name, name not unique).
             ConnectionError: If the camera is found but fails to start the pipeline or no RealSense devices are detected at all.
             RuntimeError: If the pipeline starts but fails to apply requested settings.
         """
@@ -206,31 +190,22 @@ class RealSenseCamera(Camera):
                 f"Failed to open {self}.Run `lerobot-find-cameras realsense` to find available cameras."
             ) from e
 
-        try:
-            self._configure_capture_settings()
-            self._configure_sensor_options()
-            self._start_read_thread()
+        self._configure_capture_settings()
+        self._start_read_thread()
 
-            # NOTE(Steven/Caroline): Enforcing at least one second of warmup as RS cameras need a bit of time before the first read. If we don't wait, the first read from the warmup will raise.
-            self.warmup_s = max(self.warmup_s, 1)
+        # NOTE(Steven/Caroline): Enforcing at least one second of warmup as RS cameras need a bit of time before the first read. If we don't wait, the first read from the warmup will raise.
+        self.warmup_s = max(self.warmup_s, 1)
 
-            warmup_read = self.async_read if self.use_rgb else self.async_read_depth
-            start_time = time.time()
-            while time.time() - start_time < self.warmup_s:
-                warmup_read(timeout_ms=self.warmup_s * 1000)
-                time.sleep(0.1)
-            with self.frame_lock:
-                if (self.use_rgb and self.latest_color_frame is None) or (
-                    self.use_depth and self.latest_depth_frame is None
-                ):
-                    raise ConnectionError(f"{self} failed to capture frames during warmup.")
-        except BaseException:
-            try:
-                self._cleanup_resources()
-            except Exception:
-                logger.exception(f"Failed to fully clean up {self} after connect() failed.")
-            self._reset_connection_settings()
-            raise
+        warmup_read = self.async_read if self.use_rgb else self.async_read_depth
+        start_time = time.time()
+        while time.time() - start_time < self.warmup_s:
+            warmup_read(timeout_ms=self.warmup_s * 1000)
+            time.sleep(0.1)
+        with self.frame_lock:
+            if (self.use_rgb and self.latest_color_frame is None) or (
+                self.use_depth and self.latest_depth_frame is None
+            ):
+                raise ConnectionError(f"{self} failed to capture frames during warmup.")
 
         logger.info(f"{self} connected.")
 
@@ -364,114 +339,6 @@ class RealSenseCamera(Camera):
         self.new_frame_event.clear()
         return self._async_read(timeout_ms=10000, read_depth=read_depth)
 
-    def _get_color_sensor(self) -> "rs.sensor":
-        """Returns the dedicated "RGB Camera" sensor that controls the color stream.
-
-        Manual color controls are only applied to a dedicated RGB module. Cameras
-        without one (e.g. the D405, whose color stream comes from the shared
-        "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.")
-
-        device = self.rs_profile.get_device()
-        sensors = {s.get_info(rs.camera_info.name): s for s in device.query_sensors()}
-
-        if "RGB Camera" in sensors:
-            return sensors["RGB Camera"]
-
-        available = list(sensors.keys())
-        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."""
-        try:
-            sensor.set_option(option, value)
-        except Exception as e:
-            range_info = ""
-            try:
-                option_range = sensor.get_option_range(option)
-                range_info = (
-                    f" (supported range: min={option_range.min}, max={option_range.max}, "
-                    f"step={option_range.step}, default={option_range.default})"
-                )
-            except Exception:
-                range_info = " (option range unavailable)"
-            raise ValueError(
-                f"{self}: failed to set {label} to {value}{range_info}. Original error: {e}"
-            ) from e
-
-    def _configure_sensor_options(self) -> None:
-        """Applies manual sensor options (exposure, gain, white balance) to the color sensor.
-
-        When exposure or gain is set, auto-exposure is disabled first. When white_balance
-        is set, auto white balance is disabled first. An omitted option is left unchanged,
-        and configuration is skipped entirely if all options are omitted.
-
-        Raises:
-            ValueError: If the sensor does not support a requested option or a requested
-                value is invalid. Invalid-value errors include the option name, requested
-                value, and supported range when available.
-        """
-        if self.exposure is None and self.gain is None and self.white_balance is None:
-            return
-
-        color_sensor = self._get_color_sensor()
-
-        requested_options = (
-            (rs.option.exposure, self.exposure, "exposure"),
-            (rs.option.gain, self.gain, "gain"),
-            (rs.option.white_balance, self.white_balance, "white balance"),
-        )
-        unsupported_options = [
-            label
-            for option, value, label in requested_options
-            if value is not None and not color_sensor.supports(option)
-        ]
-        if unsupported_options:
-            raise ValueError(
-                f"{self}: color sensor does not support requested manual options: {unsupported_options}."
-            )
-
-        manual_exposure_requested = self.exposure is not None or self.gain is not None
-        if manual_exposure_requested:
-            if color_sensor.supports(rs.option.enable_auto_exposure):
-                self._set_sensor_option(color_sensor, rs.option.enable_auto_exposure, 0, "auto-exposure")
-                logger.info(f"{self} auto-exposure disabled.")
-            else:
-                logger.warning(
-                    f"{self} sensor does not support disabling auto-exposure; "
-                    "applying manual exposure/gain directly."
-                )
-
-        if self.exposure is not None:
-            self._set_sensor_option(color_sensor, rs.option.exposure, self.exposure, "exposure")
-            logger.info(f"{self} exposure set to {self.exposure}.")
-
-        if self.gain is not None:
-            self._set_sensor_option(color_sensor, rs.option.gain, self.gain, "gain")
-            logger.info(f"{self} gain set to {self.gain}.")
-
-        if self.white_balance is not None:
-            if color_sensor.supports(rs.option.enable_auto_white_balance):
-                self._set_sensor_option(
-                    color_sensor, rs.option.enable_auto_white_balance, 0, "auto white balance"
-                )
-                logger.info(f"{self} auto white balance disabled.")
-            else:
-                logger.warning(
-                    f"{self} sensor does not support disabling auto white balance; "
-                    "applying manual white balance directly."
-                )
-            self._set_sensor_option(
-                color_sensor, rs.option.white_balance, self.white_balance, "white balance"
-            )
-            logger.info(f"{self} white balance set to {self.white_balance}.")
-
     @check_if_not_connected
     def read_depth(self, timeout_ms: int = 200) -> NDArray[Any]:
         """
@@ -674,27 +541,6 @@ class RealSenseCamera(Camera):
             self.latest_timestamp = None
             self.new_frame_event.clear()
 
-    def _cleanup_resources(self) -> None:
-        """Stop background reads and stop the pipeline, including after partial setup."""
-        read_thread = self.thread
-        rs_pipeline = self.rs_pipeline
-
-        try:
-            self._stop_read_thread()
-        finally:
-            self.rs_pipeline = None
-            self.rs_profile = None
-            try:
-                if rs_pipeline is not None:
-                    rs_pipeline.stop()
-            finally:
-                # Stopping the pipeline may unblock a hardware read that outlived
-                # the first bounded join in _stop_read_thread().
-                if read_thread is not None and read_thread.is_alive():
-                    read_thread.join(timeout=2.0)
-                    if read_thread.is_alive():  # pragma: no cover
-                        logger.warning(f"{self} read thread remained alive after stopping the pipeline.")
-
     def _async_read(self, timeout_ms: float, read_depth: bool = False) -> NDArray[Any]:
         """Shared helper for :meth:`async_read`/:meth:`async_read_depth`: return the latest buffered frame."""
         if self.thread is None or not self.thread.is_alive():
@@ -838,5 +684,18 @@ class RealSenseCamera(Camera):
                 f"Attempted to disconnect {self}, but it appears already disconnected."
             )
 
-        self._cleanup_resources()
+        if self.thread is not None:
+            self._stop_read_thread()
+
+        if self.rs_pipeline is not None:
+            self.rs_pipeline.stop()
+            self.rs_pipeline = None
+            self.rs_profile = None
+
+        with self.frame_lock:
+            self.latest_color_frame = None
+            self.latest_depth_frame = None
+            self.latest_timestamp = None
+            self.new_frame_event.clear()
+
         logger.info(f"{self} disconnected.")

src/lerobot/cameras/realsense/configuration_realsense.py

@@ -46,17 +46,6 @@ class RealSenseCameraConfig(CameraConfig):
         use_depth: Whether to enable depth stream. Defaults to False.
         rotation: Image rotation setting (0°, 90°, 180°, or 270°). Defaults to no rotation.
         warmup_s: Time reading frames before returning from connect (in seconds)
-        exposure: Manual exposure value for the color sensor. When set, auto-exposure is
-            disabled and this fixed value is used. Valid ranges are camera-model specific
-            and reported if the value is rejected. Defaults to None (leave unchanged).
-        gain: Manual gain value for the color sensor. When set, auto-exposure is disabled
-            and this fixed gain is used, which also freezes exposure at its current value
-            when no exposure is configured. Valid ranges are camera-model specific and
-            reported if the value is rejected. Defaults to None (leave unchanged).
-        white_balance: Manual white balance value for the color sensor. When set, auto
-            white balance is disabled and this fixed value is used. Valid ranges are
-            camera-model specific and reported if the value is rejected. Defaults to None
-            (leave unchanged).
 
     Note:
         - Either name or serial_number must be specified.
@@ -72,9 +61,6 @@ class RealSenseCameraConfig(CameraConfig):
     use_depth: bool = False
     rotation: Cv2Rotation = Cv2Rotation.NO_ROTATION
     warmup_s: int = 1
-    exposure: int | None = None
-    gain: int | None = None
-    white_balance: int | None = None
 
     def __post_init__(self) -> None:
         self.color_mode = ColorMode(self.color_mode)
@@ -83,18 +69,6 @@ class RealSenseCameraConfig(CameraConfig):
         if not self.use_rgb and not self.use_depth:
             raise ValueError("At least one of `use_rgb` or `use_depth` must be enabled.")
 
-        manual_color_options = {
-            "exposure": self.exposure,
-            "gain": self.gain,
-            "white_balance": self.white_balance,
-        }
-        configured_color_options = [name for name, value in manual_color_options.items() if value is not None]
-        if configured_color_options and not self.use_rgb:
-            raise ValueError(
-                "Manual color sensor options require `use_rgb=True`. "
-                f"Configured options: {configured_color_options}."
-            )
-
         values = (self.fps, self.width, self.height)
         if any(v is not None for v in values) and any(v is None for v in values):
             raise ValueError(

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/common/train_utils.py

@@ -53,7 +53,11 @@ def get_step_checkpoint_dir(output_dir: Path, total_steps: int, step: int) -> Pa
 
 
 def save_training_step(
-    step: int, save_dir: Path, num_processes: int | None = None, batch_size: int | None = None
+    step: int,
+    save_dir: Path,
+    num_processes: int | None = None,
+    batch_size: int | None = None,
+    num_workers: int | None = None,
 ) -> None:
     state: dict = {"step": step}
     # num_processes and batch_size are recorded so a resumed run can detect a changed world size or
@@ -64,6 +68,8 @@ def save_training_step(
         state["num_processes"] = num_processes
     if batch_size is not None:
         state["batch_size"] = batch_size
+    if num_workers is not None:
+        state["num_workers"] = num_workers
     write_json(state, save_dir / TRAINING_STEP)
 
 
@@ -82,6 +88,11 @@ def load_training_batch_size(checkpoint_dir: Path) -> int | None:
     return load_json(checkpoint_dir / TRAINING_STATE_DIR / TRAINING_STEP).get("batch_size")
 
 
+def load_training_num_workers(checkpoint_dir: Path) -> int | None:
+    """DataLoader worker count recorded at checkpoint time, or None for older checkpoints."""
+    return load_json(checkpoint_dir / TRAINING_STATE_DIR / TRAINING_STEP).get("num_workers")
+
+
 def update_last_checkpoint(checkpoint_dir: Path) -> Path:
     last_checkpoint_dir = checkpoint_dir.parent / LAST_CHECKPOINT_LINK
     if last_checkpoint_dir.is_symlink():
@@ -101,6 +112,7 @@ def save_checkpoint(
     postprocessor: PolicyProcessorPipeline | None = None,
     num_processes: int | None = None,
     batch_size: int | None = None,
+    num_workers: int | None = None,
     model_state_dict: dict | None = None,
     optim_state_dict: dict | None = None,
 ) -> None:
@@ -132,6 +144,8 @@ def save_checkpoint(
             resume. Defaults to None (not recorded).
         batch_size (int | None, optional): Per-process batch size to record for sample-exact
             resume. Defaults to None (not recorded).
+        num_workers (int | None, optional): Per-process DataLoader worker count to record for
+            sample-exact streaming resume. Defaults to None (not recorded).
         model_state_dict: Pre-gathered full (unsharded) model state dict. Required under FSDP,
             where `policy.state_dict()` would return sharded tensors; the caller gathers it via a
             cross-rank collective and passes it here so rank 0 can write it directly. It holds
@@ -160,6 +174,7 @@ def save_checkpoint(
         scheduler,
         num_processes=num_processes,
         batch_size=batch_size,
+        num_workers=num_workers,
         optim_state_dict=optim_state_dict,
     )
 
@@ -171,6 +186,7 @@ def save_training_state(
     scheduler: LRScheduler | None = None,
     num_processes: int | None = None,
     batch_size: int | None = None,
+    num_workers: int | None = None,
     optim_state_dict: dict | None = None,
 ) -> None:
     """
@@ -185,12 +201,20 @@ def save_training_state(
             Defaults to None.
         num_processes (int | None, optional): Distributed world size to record. Defaults to None.
         batch_size (int | None, optional): Per-process batch size to record. Defaults to None.
+        num_workers (int | None, optional): Per-process DataLoader worker count to record.
+            Defaults to None.
         optim_state_dict: Pre-gathered full optimizer state dict (for FSDP). Saved instead of
             `optimizer.state_dict()` when provided. Defaults to None.
     """
     save_dir = checkpoint_dir / TRAINING_STATE_DIR
     save_dir.mkdir(parents=True, exist_ok=True)
-    save_training_step(train_step, save_dir, num_processes=num_processes, batch_size=batch_size)
+    save_training_step(
+        train_step,
+        save_dir,
+        num_processes=num_processes,
+        batch_size=batch_size,
+        num_workers=num_workers,
+    )
     save_rng_state(save_dir)
     if optimizer is not None:
         save_optimizer_state(optimizer, save_dir, optim_state_dict=optim_state_dict)

src/lerobot/configs/dataset.py

@@ -71,19 +71,13 @@ class DatasetRecordConfig:
     # Number of threads per encoder instance. None = auto (codec default).
     # Lower values reduce CPU usage, maps to 'lp' (via svtav1-params) for libsvtav1 and 'threads' for h264/hevc..
     encoder_threads: int | None = None
-    # Skip appending the date-time tag to repo_id, keeping the user-provided name as-is
-    # (e.g. self-managed versioned names intended for a later `lerobot-edit-dataset merge`).
-    no_stamp: bool = False
 
     def stamp_repo_id(self) -> None:
         """Append a date-time tag to ``repo_id`` so each recording session gets a unique name.
 
         Must be called explicitly at dataset *creation* time — not on resume,
         where the existing ``repo_id`` (already stamped) must be preserved.
-        No-op when ``no_stamp`` is set, preserving a user-managed ``repo_id``.
         """
-        if self.no_stamp:
-            return
         if self.repo_id:
             timestamp = datetime.now().strftime("%Y%m%d_%H%M%S")
             self.repo_id = f"{self.repo_id}_{timestamp}"

src/lerobot/configs/default.py

@@ -44,6 +44,22 @@ class DatasetConfig:
     # Has no effect on datasets without depth cameras.
     depth_output_unit: str = DEFAULT_DEPTH_UNIT
     streaming: bool = False
+    # Optional data-plane root used by training-time streaming. Metadata still resolves from repo_id/root.
+    streaming_data_root: str | None = None
+    # Number of complete episodes mixed by the rank-level exact-coverage sampler.
+    streaming_episode_pool_size: int = 32
+    # Complete episodes fetched ahead of the current admission frontier.
+    streaming_prefetch_episodes: int = 8
+    # Hard per-rank cap for synthesized episode-video bytes.
+    streaming_byte_budget_gb: float = 8.0
+    # Parallel sample assembly/decode workers and their bounded in-order result queue.
+    streaming_decode_threads: int = 2
+    streaming_decoded_queue_size: int = 8
+    # Independent decoder-state cap. None covers every camera in the configured episode pool.
+    streaming_max_open_decoders: int | None = None
+    # Per-rank native HTTP limits. None preserves the fetcher's worker-derived default.
+    streaming_native_http_connections: int | None = None
+    streaming_native_http_subranges: int = 1
     # Fraction of episodes held out per task for offline evaluation (0.0 = disabled).
     eval_split: float = 0.0
 
@@ -54,6 +70,22 @@ class DatasetConfig:
             )
         if not (0.0 <= self.eval_split < 1.0):
             raise ValueError(f"eval_split must be in [0.0, 1.0), got {self.eval_split}")
+        if self.streaming_episode_pool_size <= 0:
+            raise ValueError("streaming_episode_pool_size must be positive")
+        if self.streaming_prefetch_episodes < 0:
+            raise ValueError("streaming_prefetch_episodes must be non-negative")
+        if self.streaming_byte_budget_gb <= 0:
+            raise ValueError("streaming_byte_budget_gb must be positive")
+        if self.streaming_decode_threads <= 0:
+            raise ValueError("streaming_decode_threads must be positive")
+        if self.streaming_decoded_queue_size <= 0:
+            raise ValueError("streaming_decoded_queue_size must be positive")
+        if self.streaming_max_open_decoders is not None and self.streaming_max_open_decoders <= 0:
+            raise ValueError("streaming_max_open_decoders must be positive")
+        if self.streaming_native_http_connections is not None and self.streaming_native_http_connections <= 0:
+            raise ValueError("streaming_native_http_connections must be positive")
+        if self.streaming_native_http_subranges <= 0:
+            raise ValueError("streaming_native_http_subranges must be positive")
         if self.episodes is not None:
             if any(ep < 0 for ep in self.episodes):
                 raise ValueError(

src/lerobot/configs/policies.py

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

src/lerobot/configs/rewards.py

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

src/lerobot/configs/train.py

@@ -194,11 +194,7 @@ class TrainPipelineConfig(HubMixin):
             )
 
         if Path(config_path).resolve().exists():
-            # `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
+            policy_dir = Path(config_path).parent
             self.checkpoint_path = policy_dir.parent
         elif self.job.is_remote:
             return

src/lerobot/datasets/aggregate.py

@@ -19,7 +19,6 @@ import copy
 import logging
 import shutil
 from pathlib import Path
-from typing import Any, NotRequired, TypedDict
 
 import datasets
 import pandas as pd
@@ -50,32 +49,8 @@ from .utils import (
 )
 from .video_utils import concatenate_video_files, get_video_duration_in_s
 
-logger = logging.getLogger(__name__)
 
-type FeatureDict = dict[str, dict[str, Any]]
-type ChunkFile = tuple[int, int]
-
-
-class IndexState(TypedDict):
-    chunk: int
-    file: int
-    src_to_dst: NotRequired[dict[ChunkFile, ChunkFile]]
-
-
-class VideoIndex(TypedDict):
-    chunk: int
-    file: int
-    latest_duration: float
-    episode_duration: float
-    src_to_offset: NotRequired[dict[ChunkFile, float]]
-    src_to_dst: NotRequired[dict[ChunkFile, ChunkFile]]
-    dst_file_durations: NotRequired[dict[ChunkFile, float]]
-
-
-type VideoIndexState = dict[str, VideoIndex]
-
-
-def merge_video_feature_info_for_aggregate(all_metadata: list[LeRobotDatasetMetadata]) -> FeatureDict:
+def merge_video_feature_info_for_aggregate(all_metadata: list[LeRobotDatasetMetadata]) -> dict[str, dict]:
     """Create a merged video feature info dictionary for aggregation. The video encoder info is merged field-by-field: each key is kept only when every source agrees; otherwise that key is set to ``null`` (or ``{}`` for ``video.extra_options``) and a warning is logged.
 
     Args:
@@ -84,14 +59,14 @@ def merge_video_feature_info_for_aggregate(all_metadata: list[LeRobotDatasetMeta
     Returns:
         dict: A dictionary of merged video feature info.
     """
-    merged_info: FeatureDict = copy.deepcopy(all_metadata[0].features)
+    merged_info = copy.deepcopy(all_metadata[0].features)
     video_keys = [k for k in merged_info if merged_info[k].get("dtype") == "video"]
 
     for vk in video_keys:
         video_infos = [m.features.get(vk, {}).get("info") or {} for m in all_metadata]
         base_video_info = video_infos[0]
 
-        merged_encoder_info: dict[str, Any] = {}
+        merged_encoder_info: dict = {}
         fallback_keys: list[str] = []
         for info_key in VIDEO_ENCODER_INFO_KEYS:
             values = [info.get(info_key, None) for info in video_infos]
@@ -105,7 +80,7 @@ def merge_video_feature_info_for_aggregate(all_metadata: list[LeRobotDatasetMeta
                 merged_encoder_info[info_key] = {} if info_key == "video.extra_options" else None
 
         if fallback_keys:
-            logger.warning(
+            logging.warning(
                 f"Merging heterogeneous or incomplete video encoder metadata for feature {vk}. "
                 f"Setting these keys to null: {fallback_keys}.",
             )
@@ -117,7 +92,7 @@ def merge_video_feature_info_for_aggregate(all_metadata: list[LeRobotDatasetMeta
     return merged_info
 
 
-def validate_all_metadata(all_metadata: list[LeRobotDatasetMetadata]) -> tuple[int, str | None, FeatureDict]:
+def validate_all_metadata(all_metadata: list[LeRobotDatasetMetadata]):
     """Validates that all dataset metadata have consistent properties.
 
     Ensures all datasets have the same fps, robot_type, and features to guarantee
@@ -154,9 +129,7 @@ def validate_all_metadata(all_metadata: list[LeRobotDatasetMetadata]) -> tuple[i
     return fps, robot_type, features
 
 
-def update_data_df(
-    df: pd.DataFrame, src_meta: LeRobotDatasetMetadata, dst_meta: LeRobotDatasetMetadata
-) -> pd.DataFrame:
+def update_data_df(df, src_meta, dst_meta):
     """Updates a data DataFrame with new indices and task mappings for aggregation.
 
     Adjusts episode indices, frame indices, and task indices to account for
@@ -181,12 +154,12 @@ def update_data_df(
 
 
 def update_meta_data(
-    df: pd.DataFrame,
-    dst_meta: LeRobotDatasetMetadata,
-    meta_idx: IndexState,
-    data_idx: IndexState,
-    videos_idx: VideoIndexState,
-) -> pd.DataFrame:
+    df,
+    dst_meta,
+    meta_idx,
+    data_idx,
+    videos_idx,
+):
     """Updates metadata DataFrame with new chunk, file, and timestamp indices.
 
     Adjusts all indices and timestamps to account for previously aggregated
@@ -316,7 +289,7 @@ def aggregate_datasets(
     chunk_size: int | None = None,
     concatenate_videos: bool = True,
     concatenate_data: bool = True,
-) -> None:
+):
     """Aggregates multiple LeRobot datasets into a single unified dataset.
 
     This is the main function that orchestrates the aggregation process by:
@@ -336,7 +309,7 @@ def aggregate_datasets(
         concatenate_videos: When False, keep one mp4 per source file instead of packing into shards.
         concatenate_data: When False, keep one parquet per source file instead of packing into shards.
     """
-    logger.info("Start aggregate_datasets")
+    logging.info("Start aggregate_datasets")
 
     if data_files_size_in_mb is None:
         data_files_size_in_mb = DEFAULT_DATA_FILE_SIZE_IN_MB
@@ -368,15 +341,15 @@ def aggregate_datasets(
         video_files_size_in_mb=video_files_size_in_mb,
     )
 
-    logger.info("Find all tasks")
+    logging.info("Find all tasks")
     unique_tasks = pd.concat([m.tasks for m in all_metadata]).index.unique()
     dst_meta.tasks = pd.DataFrame(
         {"task_index": range(len(unique_tasks))}, index=pd.Index(unique_tasks, name="task")
     )
 
-    meta_idx: IndexState = {"chunk": 0, "file": 0}
-    data_idx: IndexState = {"chunk": 0, "file": 0}
-    videos_idx: VideoIndexState = {
+    meta_idx = {"chunk": 0, "file": 0}
+    data_idx = {"chunk": 0, "file": 0}
+    videos_idx = {
         key: {"chunk": 0, "file": 0, "latest_duration": 0, "episode_duration": 0} for key in video_keys
     }
 
@@ -400,17 +373,12 @@ def aggregate_datasets(
         dst_meta.info.total_frames += src_meta.total_frames
 
     finalize_aggregation(dst_meta, all_metadata)
-    logger.info("Aggregation complete.")
+    logging.info("Aggregation complete.")
 
 
 def aggregate_videos(
-    src_meta: LeRobotDatasetMetadata,
-    dst_meta: LeRobotDatasetMetadata,
-    videos_idx: VideoIndexState,
-    video_files_size_in_mb: float,
-    chunk_size: int,
-    concatenate_videos: bool = True,
-) -> VideoIndexState:
+    src_meta, dst_meta, videos_idx, video_files_size_in_mb, chunk_size, concatenate_videos=True
+):
     """Aggregates video chunks from a source dataset into the destination dataset.
 
     Handles video file concatenation and rotation based on file size limits.
@@ -438,16 +406,15 @@ def aggregate_videos(
             videos_idx[key]["dst_file_durations"] = {}
 
     for key, video_idx in videos_idx.items():
-        unique_chunk_file_pairs: list[ChunkFile] = sorted(
-            {
-                (chunk, file)
-                for chunk, file in zip(
-                    src_meta.episodes[f"videos/{key}/chunk_index"],
-                    src_meta.episodes[f"videos/{key}/file_index"],
-                    strict=False,
-                )
-            }
-        )
+        unique_chunk_file_pairs = {
+            (chunk, file)
+            for chunk, file in zip(
+                src_meta.episodes[f"videos/{key}/chunk_index"],
+                src_meta.episodes[f"videos/{key}/file_index"],
+                strict=False,
+            )
+        }
+        unique_chunk_file_pairs = sorted(unique_chunk_file_pairs)
 
         chunk_idx = video_idx["chunk"]
         file_idx = video_idx["file"]
@@ -522,14 +489,7 @@ def aggregate_videos(
     return videos_idx
 
 
-def aggregate_data(
-    src_meta: LeRobotDatasetMetadata,
-    dst_meta: LeRobotDatasetMetadata,
-    data_idx: IndexState,
-    data_files_size_in_mb: float,
-    chunk_size: int,
-    concatenate_data: bool = True,
-) -> IndexState:
+def aggregate_data(src_meta, dst_meta, data_idx, data_files_size_in_mb, chunk_size, concatenate_data=True):
     """Aggregates data chunks from a source dataset into the destination dataset.
 
     Reads source data files, updates indices to match the aggregated dataset,
@@ -550,16 +510,14 @@ def aggregate_data(
     Returns:
         dict: Updated data_idx with current chunk and file indices.
     """
-    unique_chunk_file_ids: list[ChunkFile] = sorted(
-        {
-            (c, f)
-            for c, f in zip(
-                src_meta.episodes["data/chunk_index"],
-                src_meta.episodes["data/file_index"],
-                strict=False,
-            )
-        }
-    )
+    unique_chunk_file_ids = {
+        (c, f)
+        for c, f in zip(
+            src_meta.episodes["data/chunk_index"], src_meta.episodes["data/file_index"], strict=False
+        )
+    }
+
+    unique_chunk_file_ids = sorted(unique_chunk_file_ids)
     contains_images = len(dst_meta.image_keys) > 0
 
     # retrieve features schema for proper image typing in parquet
@@ -567,7 +525,7 @@ def aggregate_data(
 
     # Track source to destination file mapping for metadata update
     # This is critical for handling datasets that are already results of a merge
-    src_to_dst: dict[ChunkFile, ChunkFile] = {}
+    src_to_dst: dict[tuple[int, int], tuple[int, int]] = {}
 
     for src_chunk_idx, src_file_idx in unique_chunk_file_ids:
         src_path = src_meta.root / DEFAULT_DATA_PATH.format(
@@ -606,13 +564,7 @@ def aggregate_data(
     return data_idx
 
 
-def aggregate_metadata(
-    src_meta: LeRobotDatasetMetadata,
-    dst_meta: LeRobotDatasetMetadata,
-    meta_idx: IndexState,
-    data_idx: IndexState,
-    videos_idx: VideoIndexState,
-) -> IndexState:
+def aggregate_metadata(src_meta, dst_meta, meta_idx, data_idx, videos_idx):
     """Aggregates metadata from a source dataset into the destination dataset.
 
     Reads source metadata files, updates all indices and timestamps,
@@ -628,16 +580,16 @@ def aggregate_metadata(
     Returns:
         dict: Updated meta_idx with current chunk and file indices.
     """
-    chunk_file_ids: list[ChunkFile] = sorted(
-        {
-            (c, f)
-            for c, f in zip(
-                src_meta.episodes["meta/episodes/chunk_index"],
-                src_meta.episodes["meta/episodes/file_index"],
-                strict=False,
-            )
-        }
-    )
+    chunk_file_ids = {
+        (c, f)
+        for c, f in zip(
+            src_meta.episodes["meta/episodes/chunk_index"],
+            src_meta.episodes["meta/episodes/file_index"],
+            strict=False,
+        )
+    }
+
+    chunk_file_ids = sorted(chunk_file_ids)
     for chunk_idx, file_idx in chunk_file_ids:
         src_path = src_meta.root / DEFAULT_EPISODES_PATH.format(chunk_index=chunk_idx, file_index=file_idx)
         df = pd.read_parquet(src_path)
@@ -670,16 +622,16 @@ def aggregate_metadata(
 def append_or_create_parquet_file(
     df: pd.DataFrame,
     src_path: Path,
-    idx: IndexState,
+    idx: dict[str, int],
     max_mb: float,
     chunk_size: int,
     default_path: str,
     contains_images: bool = False,
-    aggr_root: Path | None = None,
+    aggr_root: Path = None,
     hf_features: datasets.Features | None = None,
     concatenate: bool = True,
     one_row_group_per_episode: bool = False,
-) -> tuple[IndexState, ChunkFile]:
+) -> tuple[dict[str, int], tuple[int, int]]:
     """Appends data to an existing parquet file or creates a new one based on size constraints.
 
     Manages file rotation when size limits are exceeded to prevent individual files
@@ -702,13 +654,7 @@ def append_or_create_parquet_file(
     Returns:
         tuple: (updated_idx, (dst_chunk, dst_file)) where updated_idx is the index dict
                and (dst_chunk, dst_file) is the actual destination file the data was written to.
-
-    Raises:
-        ValueError: If aggr_root is not provided.
     """
-    if aggr_root is None:
-        raise ValueError("aggr_root must be provided.")
-
     dst_chunk, dst_file = idx["chunk"], idx["file"]
     dst_path = aggr_root / default_path.format(chunk_index=dst_chunk, file_index=dst_file)
 
@@ -752,9 +698,7 @@ def append_or_create_parquet_file(
     return idx, (dst_chunk, dst_file)
 
 
-def finalize_aggregation(
-    aggr_meta: LeRobotDatasetMetadata, all_metadata: list[LeRobotDatasetMetadata]
-) -> None:
+def finalize_aggregation(aggr_meta, all_metadata):
     """Finalizes the dataset aggregation by writing summary files and statistics.
 
     Writes the tasks file, info file with total counts and splits, and
@@ -764,16 +708,16 @@ def finalize_aggregation(
         aggr_meta: Aggregated dataset metadata.
         all_metadata: List of all source dataset metadata objects.
     """
-    logger.info("write tasks")
+    logging.info("write tasks")
     write_tasks(aggr_meta.tasks, aggr_meta.root)
 
-    logger.info("write info")
+    logging.info("write info")
     aggr_meta.info.total_tasks = len(aggr_meta.tasks)
     aggr_meta.info.total_episodes = sum(m.total_episodes for m in all_metadata)
     aggr_meta.info.total_frames = sum(m.total_frames for m in all_metadata)
     aggr_meta.info.splits = {"train": f"0:{sum(m.total_episodes for m in all_metadata)}"}
     write_info(aggr_meta.info, aggr_meta.root)
 
-    logger.info("write stats")
+    logging.info("write stats")
     aggr_meta.stats = aggregate_stats([m.stats for m in all_metadata])
     write_stats(aggr_meta.stats, aggr_meta.root)

src/lerobot/datasets/dataset_metadata.py

@@ -188,8 +188,8 @@ class LeRobotDatasetMetadata:
     def _load_metadata(self):
         self.info = load_info(self.root)
         check_version_compatibility(self.repo_id, self._version, CODEBASE_VERSION)
-        self.tasks = load_tasks(self.root) if self.total_tasks > 0 else None
-        self.episodes = load_episodes(self.root) if self.total_episodes > 0 else None
+        self.tasks = load_tasks(self.root)
+        self.episodes = load_episodes(self.root)
         self.stats = load_stats(self.root)
 
     def ensure_readable(self) -> None:

src/lerobot/datasets/dataset_tools.py

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

src/lerobot/datasets/factory.py

@@ -66,7 +66,9 @@ def resolve_delta_timestamps(
     return delta_timestamps
 
 
-def make_dataset(cfg: TrainPipelineConfig) -> LeRobotDataset | MultiLeRobotDataset:
+def make_dataset(
+    cfg: TrainPipelineConfig,
+) -> LeRobotDataset | StreamingLeRobotDataset | MultiLeRobotDataset:
     """Handles the logic of setting up delta timestamps and image transforms before creating a dataset.
 
     Args:
@@ -108,9 +110,21 @@ def make_dataset(cfg: TrainPipelineConfig) -> LeRobotDataset | MultiLeRobotDatas
                 delta_timestamps=delta_timestamps,
                 image_transforms=image_transforms,
                 revision=cfg.dataset.revision,
-                max_num_shards=cfg.num_workers,
+                max_num_shards=max(1, cfg.num_workers),
                 tolerance_s=cfg.tolerance_s,
                 return_uint8=True,
+                depth_output_unit=cfg.dataset.depth_output_unit,
+                video_backend=cfg.dataset.video_backend,
+                data_root=cfg.dataset.streaming_data_root,
+                episode_pool_size=cfg.dataset.streaming_episode_pool_size,
+                prefetch_episodes=cfg.dataset.streaming_prefetch_episodes,
+                byte_budget_gb=cfg.dataset.streaming_byte_budget_gb,
+                decode_threads=cfg.dataset.streaming_decode_threads,
+                decoded_queue_size=cfg.dataset.streaming_decoded_queue_size,
+                max_open_decoders=cfg.dataset.streaming_max_open_decoders,
+                native_http_connections=cfg.dataset.streaming_native_http_connections,
+                native_http_subranges=cfg.dataset.streaming_native_http_subranges,
+                repeat=True,
             )
     else:
         raise NotImplementedError("The MultiLeRobotDataset isn't supported for now.")
@@ -138,7 +152,10 @@ def make_dataset(cfg: TrainPipelineConfig) -> LeRobotDataset | MultiLeRobotDatas
 
 def make_train_eval_datasets(
     cfg: TrainPipelineConfig,
-) -> tuple[LeRobotDataset | MultiLeRobotDataset, LeRobotDataset | None]:
+) -> tuple[
+    LeRobotDataset | StreamingLeRobotDataset | MultiLeRobotDataset,
+    LeRobotDataset | None,
+]:
     """Create train and optional eval datasets by splitting episodes based on eval_split.
 
     The last ceil(n_episodes * eval_split) episodes per task are held out for evaluation.
@@ -181,17 +198,43 @@ def make_train_eval_datasets(
         ImageTransforms(cfg.dataset.image_transforms) if cfg.dataset.image_transforms.enable else None
     )
 
-    train_dataset = LeRobotDataset(
-        cfg.dataset.repo_id,
-        root=cfg.dataset.root,
-        episodes=train_episodes,
-        delta_timestamps=delta_timestamps,
-        image_transforms=train_image_transforms,
-        revision=cfg.dataset.revision,
-        video_backend=cfg.dataset.video_backend,
-        return_uint8=True,
-        tolerance_s=cfg.tolerance_s,
-    )
+    if cfg.dataset.streaming:
+        train_dataset = StreamingLeRobotDataset(
+            cfg.dataset.repo_id,
+            root=cfg.dataset.root,
+            episodes=train_episodes,
+            delta_timestamps=delta_timestamps,
+            image_transforms=train_image_transforms,
+            revision=cfg.dataset.revision,
+            max_num_shards=max(1, cfg.num_workers),
+            tolerance_s=cfg.tolerance_s,
+            return_uint8=True,
+            depth_output_unit=cfg.dataset.depth_output_unit,
+            video_backend=cfg.dataset.video_backend,
+            data_root=cfg.dataset.streaming_data_root,
+            episode_pool_size=cfg.dataset.streaming_episode_pool_size,
+            prefetch_episodes=cfg.dataset.streaming_prefetch_episodes,
+            byte_budget_gb=cfg.dataset.streaming_byte_budget_gb,
+            decode_threads=cfg.dataset.streaming_decode_threads,
+            decoded_queue_size=cfg.dataset.streaming_decoded_queue_size,
+            max_open_decoders=cfg.dataset.streaming_max_open_decoders,
+            native_http_connections=cfg.dataset.streaming_native_http_connections,
+            native_http_subranges=cfg.dataset.streaming_native_http_subranges,
+            repeat=True,
+        )
+    else:
+        train_dataset = LeRobotDataset(
+            cfg.dataset.repo_id,
+            root=cfg.dataset.root,
+            episodes=train_episodes,
+            delta_timestamps=delta_timestamps,
+            image_transforms=train_image_transforms,
+            revision=cfg.dataset.revision,
+            video_backend=cfg.dataset.video_backend,
+            return_uint8=True,
+            depth_output_unit=cfg.dataset.depth_output_unit,
+            tolerance_s=cfg.tolerance_s,
+        )
 
     eval_dataset = LeRobotDataset(
         cfg.dataset.repo_id,
@@ -202,6 +245,7 @@ def make_train_eval_datasets(
         revision=cfg.dataset.revision,
         video_backend=cfg.dataset.video_backend,
         return_uint8=True,
+        depth_output_unit=cfg.dataset.depth_output_unit,
         tolerance_s=cfg.tolerance_s,
     )
 

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_sidecar.py

@@ -0,0 +1,149 @@
+# Copyright 2026 The HuggingFace Inc. team. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+
+"""LeRobot metadata adapter for automatic MP4 sidecar resolution."""
+
+from __future__ import annotations
+
+import logging
+import shutil
+from pathlib import Path
+
+import fsspec
+
+from lerobot.datasets.dataset_metadata import LeRobotDatasetMetadata
+from lerobot.streaming.manifest import EpisodeVideoManifest
+from lerobot.streaming.sidecar import SidecarSpec, ensure_mp4_sidecar, sidecar_cache_path
+from lerobot.utils.constants import HF_LEROBOT_HOME
+
+DEFAULT_SIDECAR_CACHE = HF_LEROBOT_HOME / "streaming-sidecars"
+
+
+def range_backend_for_root(data_root: str) -> str:
+    """Use direct HTTP only for HF roots; all local and other fsspec protocols stay generic."""
+    return "native-http" if data_root.startswith("hf://") else "fsspec"
+
+
+def streaming_data_root(
+    meta: LeRobotDatasetMetadata,
+    *,
+    requested_root: str | Path | None,
+    configured_data_root: str | None,
+) -> str:
+    if configured_data_root is not None:
+        return configured_data_root.rstrip("/")
+    if requested_root is not None:
+        return str(Path(requested_root).expanduser())
+    return f"hf://datasets/{meta.repo_id}@{meta.revision}"
+
+
+def make_sidecar_spec(meta: LeRobotDatasetMetadata, data_root: str) -> SidecarSpec:
+    relative_paths = sorted(
+        {
+            str(meta.get_video_file_path(episode_index, video_key))
+            for episode_index in range(int(meta.total_episodes))
+            for video_key in meta.video_keys
+        }
+    )
+    root = Path(data_root).expanduser()
+    source_files: tuple[tuple[str, int | None], ...]
+    if root.is_dir():
+        source_files = tuple((path, (root / path).stat().st_size) for path in relative_paths)
+    else:
+        source_files = tuple((path, None) for path in relative_paths)
+    return SidecarSpec(
+        repo_id=meta.repo_id,
+        revision=str(meta.revision),
+        data_root=data_root.rstrip("/"),
+        source_files=source_files,
+    )
+
+
+def build_mp4_sidecar(
+    destination: str | Path,
+    spec: SidecarSpec,
+    *,
+    workers: int = 8,
+    range_backend: str = "native-http",
+    max_probe_bytes: int = 64 * 1024 * 1024,
+    token: str | bool | None = None,
+) -> None:
+    EpisodeVideoManifest.write_file_sidecar(
+        destination,
+        [path for path, _size in spec.source_files],
+        spec.data_root,
+        spec=spec,
+        range_backend=range_backend,
+        workers=workers,
+        max_probe_bytes=max_probe_bytes,
+        token=token,
+    )
+
+
+def published_sidecar_url(spec: SidecarSpec, cache_root: str | Path = DEFAULT_SIDECAR_CACHE) -> str:
+    name = sidecar_cache_path(cache_root, spec).name
+    return f"{spec.data_root}/meta/mp4-sidecars/{name}"
+
+
+def download_published_sidecar(
+    destination: Path,
+    spec: SidecarSpec,
+    *,
+    cache_root: str | Path = DEFAULT_SIDECAR_CACHE,
+    token: str | bool | None = None,
+) -> bool:
+    if Path(spec.data_root).expanduser().is_dir():
+        return False
+    source_url = published_sidecar_url(spec, cache_root)
+    storage_options = {"token": token} if token is not None and source_url.startswith("hf://") else {}
+    filesystem, source = fsspec.core.url_to_fs(source_url, **storage_options)
+    if not filesystem.exists(source):
+        return False
+    with filesystem.open(source, "rb") as remote, destination.open("wb") as local:
+        shutil.copyfileobj(remote, local)
+    return True
+
+
+def ensure_dataset_mp4_sidecar(
+    meta: LeRobotDatasetMetadata,
+    data_root: str,
+    *,
+    cache_root: str | Path = DEFAULT_SIDECAR_CACHE,
+    workers: int = 8,
+    range_backend: str = "native-http",
+    lock_timeout_s: float = 30 * 60,
+    token: str | bool | None = None,
+) -> Path | None:
+    if not meta.video_keys:
+        return None
+
+    spec = make_sidecar_spec(meta, data_root)
+    logging.info(
+        "Resolving training-time MP4 sidecar for %s@%s (%d files)",
+        spec.repo_id,
+        spec.revision,
+        len(spec.source_files),
+    )
+    return ensure_mp4_sidecar(
+        spec,
+        cache_root,
+        build=lambda path, target_spec: build_mp4_sidecar(
+            path,
+            target_spec,
+            workers=workers,
+            range_backend=range_backend,
+            token=token,
+        ),
+        download=lambda path, target_spec: download_published_sidecar(
+            path,
+            target_spec,
+            cache_root=cache_root,
+            token=token,
+        ),
+        lock_timeout_s=lock_timeout_s,
+    )

src/lerobot/datasets/video_utils.py

@@ -28,7 +28,7 @@ from dataclasses import asdict, dataclass, field
 from fractions import Fraction
 from pathlib import Path
 from threading import Lock
-from typing import Any, ClassVar
+from typing import Any, BinaryIO, ClassVar
 
 import av
 import fsspec
@@ -105,7 +105,7 @@ def decode_video_frames(
 
 
 def decode_video_frames_pyav(
-    video_path: Path | str,
+    video_path: Path | str | BinaryIO,
     timestamps: list[float],
     tolerance_s: float,
     log_loaded_timestamps: bool = False,
@@ -124,7 +124,7 @@ def decode_video_frames_pyav(
     video can be adjusted at encoding time to trade off decoding speed against file size.
 
     Args:
-        video_path: Path to the video file.
+        video_path: Path to the video file or a seekable binary file object.
         timestamps: List of timestamps (in seconds) to extract frames for.
         tolerance_s: Allowed deviation in seconds between a queried timestamp and the closest
             decoded frame.
@@ -137,7 +137,8 @@ def decode_video_frames_pyav(
         torch.Tensor of shape (len(timestamps), C, H, W).
     """
     # TODO(rcadene): also load audio stream at the same time
-    video_path = str(video_path)
+    video_source = str(video_path) if isinstance(video_path, (Path, str)) else video_path
+    video_label = str(video_path) if isinstance(video_path, (Path, str)) else "<in-memory video>"
 
     # set the first and last requested timestamps
     # Note: previous timestamps are usually loaded, since we need to access the previous key frame
@@ -151,7 +152,7 @@ def decode_video_frames_pyav(
     # av.time_base units (microseconds). `backward=True` lands us on the nearest keyframe at or
     # before `first_ts`, so we can then decode forward until we cover `last_ts`. See:
     # https://pyav.basswood-io.com/docs/stable/api/container.html#av.container.InputContainer.seek
-    with av.open(video_path) as container:
+    with av.open(video_source) as container:
         stream = container.streams.video[0]
         # Seek to the nearest keyframe at or before `first_ts` with a 1 frame margin
         container.seek(
@@ -180,7 +181,7 @@ def decode_video_frames_pyav(
 
     if not loaded_frames:
         raise FrameTimestampError(
-            f"No frames could be decoded from {video_path} in the timestamp range [{first_ts}, {last_ts}]."
+            f"No frames could be decoded from {video_label} in the timestamp range [{first_ts}, {last_ts}]."
         )
 
     query_ts = torch.tensor(timestamps)
@@ -199,7 +200,7 @@ def decode_video_frames_pyav(
             " To be safe, we advise to ignore this item during training."
             f"\nqueried timestamps: {query_ts}"
             f"\nloaded timestamps: {loaded_ts_t}"
-            f"\nvideo: {video_path}"
+            f"\nvideo: {video_label}"
             f"\nbackend: pyav"
         )
 

src/lerobot/envs/configs.py

@@ -507,7 +507,7 @@ class MetaworldEnv(EnvConfig):
 class RoboCasaEnv(EnvConfig):
     task: str = "CloseFridge"
     fps: int = 20
-    episode_length: int | None = None
+    episode_length: int = 1000
     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.lerobot_types import RobotObservation
+from lerobot.types import RobotObservation
 
 from .utils import _LazyAsyncVectorEnv, parse_camera_names
 
@@ -384,12 +384,7 @@ class LiberoEnv(gym.Env):
 
     def close(self):
         if self._env is not None:
-            try:
-                self._env.close()
-            finally:
-                # LIBERO deletes its inner env on close, so this wrapper must
-                # be recreated before the next reset.
-                self._env = None
+            self._env.close()
 
 
 def _make_env_fns(

src/lerobot/envs/metaworld.py

@@ -25,7 +25,7 @@ import metaworld.policies as policies
 import numpy as np
 from gymnasium import spaces
 
-from lerobot.lerobot_types import RobotObservation
+from 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.lerobot_types import RobotObservation
+from lerobot.types import RobotObservation
 
 from .utils import _LazyAsyncVectorEnv, parse_camera_names
 
@@ -98,19 +98,6 @@ 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.
 
@@ -167,7 +154,7 @@ 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 _get_task_horizon(task)
+        self._max_episode_steps = episode_length if episode_length is not None else 1000
 
         # 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.lerobot_types import RobotObservation
+from lerobot.types import RobotObservation
 from lerobot.utils.import_utils import _scipy_available
 
 from .utils import _LazyAsyncVectorEnv
@@ -384,9 +384,7 @@ class RoboTwinEnv(gym.Env):
 
         self._env: Any | None = None  # deferred — created on first reset() inside worker
         self._step_count: int = 0
-        self._black_frame: np.ndarray = np.zeros(
-            (self.observation_height, self.observation_width, 3), dtype=np.uint8
-        )
+        self._black_frame = np.zeros((self.observation_height, self.observation_width, 3), dtype=np.uint8)
 
         image_spaces = {
             cam: spaces.Box(

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.lerobot_types import RobotObservation
+from lerobot.types import RobotObservation
 
 from .utils import _LazyAsyncVectorEnv
 
@@ -373,7 +373,7 @@ class VLABenchEnv(gym.Env):
 
         if action.shape[0] != 7:
             # Unknown layout — fall back to zero-pad so the sim doesn't crash.
-            padded: np.ndarray = np.zeros(ctrl_dim, dtype=np.float64)
+            padded = np.zeros(ctrl_dim, dtype=np.float64)
             padded[: min(action.shape[0], ctrl_dim)] = action[:ctrl_dim]
             return padded
 

src/lerobot/motors/dynamixel/tables.py

@@ -122,9 +122,6 @@ MODEL_ENCODING_TABLE = {
     "xm430-w350": X_SERIES_ENCODINGS_TABLE,
     "xm540-w270": X_SERIES_ENCODINGS_TABLE,
     "xc430-w150": X_SERIES_ENCODINGS_TABLE,
-    "xh540-w150": X_SERIES_ENCODINGS_TABLE,
-    "xc330-t288": X_SERIES_ENCODINGS_TABLE,
-    "xc330-t181": X_SERIES_ENCODINGS_TABLE,
 }
 
 # {model: model_resolution}
@@ -137,9 +134,6 @@ MODEL_RESOLUTION = {
     "xm430-w350": 4096,
     "xm540-w270": 4096,
     "xc430-w150": 4096,
-    "xh540-w150": 4096,
-    "xc330-t288": 4096,
-    "xc330-t181": 4096,
 }
 
 # {model: model_number}
@@ -151,9 +145,6 @@ MODEL_NUMBER_TABLE = {
     "xm430-w350": 1020,
     "xm540-w270": 1120,
     "xc430-w150": 1070,
-    "xh540-w150": 1110,
-    "xc330-t288": 1220,
-    "xc330-t181": 1210,
 }
 
 # {model: available_operating_modes}
@@ -165,9 +156,6 @@ MODEL_OPERATING_MODES = {
     "xm430-w350": [0, 1, 3, 4, 5, 16],
     "xm540-w270": [0, 1, 3, 4, 5, 16],
     "xc430-w150": [1, 3, 4, 16],
-    "xh540-w150": [0, 1, 3, 4, 5, 16],
-    "xc330-t288": [0, 1, 3, 4, 5, 16],
-    "xc330-t181": [0, 1, 3, 4, 5, 16],
 }
 
 MODEL_CONTROL_TABLE = {
@@ -178,9 +166,6 @@ MODEL_CONTROL_TABLE = {
     "xm430-w350": X_SERIES_CONTROL_TABLE,
     "xm540-w270": X_SERIES_CONTROL_TABLE,
     "xc430-w150": X_SERIES_CONTROL_TABLE,
-    "xh540-w150": X_SERIES_CONTROL_TABLE,
-    "xc330-t288": X_SERIES_CONTROL_TABLE,
-    "xc330-t181": X_SERIES_CONTROL_TABLE,
 }
 
 MODEL_BAUDRATE_TABLE = {
@@ -191,9 +176,6 @@ MODEL_BAUDRATE_TABLE = {
     "xm430-w350": X_SERIES_BAUDRATE_TABLE,
     "xm540-w270": X_SERIES_BAUDRATE_TABLE,
     "xc430-w150": X_SERIES_BAUDRATE_TABLE,
-    "xh540-w150": X_SERIES_BAUDRATE_TABLE,
-    "xc330-t288": X_SERIES_BAUDRATE_TABLE,
-    "xc330-t181": X_SERIES_BAUDRATE_TABLE,
 }
 
 AVAILABLE_BAUDRATES = [

src/lerobot/policies/eo1/processor_eo1.py

@@ -22,7 +22,6 @@ 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,
@@ -32,6 +31,7 @@ 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

@@ -42,9 +42,6 @@ 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

@@ -21,7 +21,6 @@ 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,
@@ -41,6 +40,7 @@ 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,
@@ -302,33 +302,6 @@ def _pad_evo1_stats(
     return padded_stats
 
 
-def _refresh_evo1_normalization_steps(
-    config: Evo1Config,
-    preprocessor: PolicyProcessorPipeline,
-    postprocessor: PolicyProcessorPipeline,
-) -> None:
-    """Re-pad checkpoint-loaded (un)normalizer stats/features to EVO1's fixed widths.
-
-    Loading a checkpoint injects the raw dataset stats (unpadded to max_state_dim/max_action_dim)
-    into the (un)normalizer via the generic override path in make_pre_post_processors. Those stats
-    and their declared features must be re-padded/reshaped to EVO1's fixed widths, otherwise
-    normalization fails against the padded state/action tensors (e.g. state padded to 24 vs. 8-dim
-    LIBERO stats). Padding is a no-op when stats are already at the target width.
-    """
-    normalization_features = _evo1_normalization_features(config)
-    action_features = _evo1_action_features(config)
-    for step in preprocessor.steps:
-        if isinstance(step, NormalizerProcessorStep):
-            step.features = normalization_features
-            step.stats = _pad_evo1_stats(config, step.stats)
-            step.to(device=step.device, dtype=step.dtype)
-    for step in postprocessor.steps:
-        if isinstance(step, UnnormalizerProcessorStep):
-            step.features = action_features
-            step.stats = _pad_evo1_stats(config, step.stats)
-            step.to(device=step.device, dtype=step.dtype)
-
-
 def reconcile_evo1_processors(
     config: Evo1Config,
     preprocessor: PolicyProcessorPipeline,
@@ -336,19 +309,16 @@ def reconcile_evo1_processors(
 ) -> tuple[PolicyProcessorPipeline, PolicyProcessorPipeline]:
     """Reconcile checkpoint-loaded pipelines with the current EVO1 config.
 
-    Three things cannot be restored from a serialized pipeline alone: the EVO1 batch converter
-    (converters are plain functions and are never serialized), eval-time CLI overrides of the
-    action postprocessing flags (`postprocess_action_dim`, `binarize_gripper`, `gripper_*`), and the
-    (un)normalizer stats/features when the generic override path injects raw, unpadded dataset
-    stats. This restores the converter, re-pads the normalization stats to EVO1's fixed widths, and
-    rebuilds the action step from the current config so those overrides take effect.
+    Two things cannot be restored from a serialized pipeline alone: the EVO1 batch converter
+    (converters are plain functions and are never serialized), and eval-time CLI overrides of the
+    action postprocessing flags (`postprocess_action_dim`, `binarize_gripper`, `gripper_*`). This
+    restores the converter and rebuilds the action step from the current config so those overrides
+    take effect.
     """
     # Pipelines reloaded from a checkpoint come back with the default batch converter, which drops
     # non-observation extras (embodiment_id, state_mask, custom task fields) needed by EVO1.
     preprocessor.to_transition = evo1_batch_to_transition
 
-    _refresh_evo1_normalization_steps(config, preprocessor, postprocessor)
-
     action_step = Evo1ActionProcessorStep(
         action_dim=_evo1_action_dim(config),
         binarize_gripper=config.binarize_gripper,

src/lerobot/policies/factory.py

@@ -28,7 +28,6 @@ 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,
@@ -38,25 +37,19 @@ 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,
     POLICY_PREPROCESSOR_DEFAULT_NAME,
 )
 from lerobot.utils.feature_utils import dataset_to_policy_features
-from lerobot.utils.import_utils import _peft_available, require_package
 
 from .evo1.configuration_evo1 import Evo1Config
 from .groot.configuration_groot import GrootConfig
 from .pretrained import PreTrainedPolicy
 from .utils import validate_visual_features_consistency
 
-if TYPE_CHECKING or _peft_available:
-    from peft import PeftConfig, PeftModel
-else:
-    PeftConfig = None
-    PeftModel = None
-
 
 def _reconnect_relative_absolute_steps(
     preprocessor: PolicyProcessorPipeline, postprocessor: PolicyProcessorPipeline
@@ -341,15 +334,12 @@ def make_policy(
         # Load a pretrained PEFT model on top of the policy. The pretrained path points to the folder/repo
         # of the adapter and the adapter's config contains the path to the base policy. So we need the
         # adapter config first, then load the correct policy and then apply PEFT.
-        require_package("peft", extra="peft")
+        from peft import PeftConfig, PeftModel
 
         logging.info("Loading policy's PEFT adapter.")
 
         peft_pretrained_path = str(cfg.pretrained_path)
-        peft_config = PeftConfig.from_pretrained(
-            peft_pretrained_path,
-            revision=cfg.pretrained_revision,
-        )
+        peft_config = PeftConfig.from_pretrained(peft_pretrained_path)
 
         kwargs["pretrained_name_or_path"] = peft_config.base_model_name_or_path
         if not kwargs["pretrained_name_or_path"]:
@@ -360,14 +350,9 @@ def make_policy(
                 "the adapter was trained."
             )
 
-        kwargs["revision"] = peft_config.revision
         policy = policy_cls.from_pretrained(**kwargs)
         policy = PeftModel.from_pretrained(
-            policy,
-            peft_pretrained_path,
-            config=peft_config,
-            revision=cfg.pretrained_revision,
-            is_trainable=True,
+            policy, peft_pretrained_path, config=peft_config, is_trainable=True
         )
 
     else:

src/lerobot/policies/gaussian_actor/configuration_gaussian_actor.py

@@ -37,19 +37,13 @@ def is_image_feature(key: str) -> bool:
 @dataclass
 class ConcurrencyConfig:
     """Configuration for the concurrency of the actor and learner.
-
     Possible values are:
     - "threads": Use threads for the actor and learner.
     - "processes": Use processes for the actor and learner.
-
-    ``multiprocessing_context`` selects the process-wide start method when
-    processes are used. Set it to ``None`` to preserve Python's default or a
-    method already selected by the embedding application.
     """
 
     actor: str = "threads"
     learner: str = "threads"
-    multiprocessing_context: str | None = "spawn"
 
 
 @dataclass

src/lerobot/policies/groot/modeling_groot.py

@@ -68,9 +68,6 @@ 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

@@ -50,7 +50,6 @@ if TYPE_CHECKING or _datasets_available:
 else:
     LeRobotDataset = None
 
-from lerobot.lerobot_types import EnvTransition, TransitionKey
 from lerobot.processor import (
     AbsoluteActionsProcessorStep,
     AddBatchDimensionProcessorStep,
@@ -67,6 +66,7 @@ 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

@@ -43,22 +43,11 @@ from torch.distributions import Beta
 
 from lerobot.policies.pretrained import PreTrainedPolicy
 from lerobot.utils.constants import ACTION
-from lerobot.utils.import_utils import (
-    _peft_available,
-    _scipy_available,
-    _transformers_available,
-    require_package,
-)
+from lerobot.utils.import_utils import _scipy_available, _transformers_available, require_package
 
 from ..rtc.modeling_rtc import RTCProcessor
 from .configuration_molmoact2 import MolmoAct2Config
 
-if TYPE_CHECKING or _peft_available:
-    from peft import LoraConfig, get_peft_model
-else:
-    LoraConfig = None
-    get_peft_model = None
-
 logger = logging.getLogger(__name__)
 
 
@@ -520,9 +509,6 @@ 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,
@@ -1745,11 +1731,13 @@ class MolmoAct2Policy(PreTrainedPolicy):
 
     def _build_inner_lora_config(self):
         require_package("peft", extra="molmoact2")
+        from peft import LoraConfig
 
         return LoraConfig(**self._get_inner_peft_targets())
 
     def _apply_lora_adapters(self) -> None:
         require_package("peft", extra="molmoact2")
+        from peft import get_peft_model
 
         peft_config = self._build_inner_lora_config()
         self._validate_peft_config(peft_config)

src/lerobot/policies/molmoact2/processor_molmoact2.py

@@ -36,7 +36,6 @@ 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,
@@ -50,6 +49,7 @@ 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

@@ -749,9 +749,6 @@ 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

@@ -714,9 +714,6 @@ 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

@@ -22,7 +22,6 @@ 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,
@@ -34,6 +33,7 @@ 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

@@ -22,7 +22,6 @@ 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,
@@ -35,6 +34,7 @@ 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

@@ -34,22 +34,14 @@ from lerobot.configs import PreTrainedConfig
 from lerobot.configs.train import TrainPipelineConfig
 from lerobot.utils.device_utils import resolve_safetensors_device
 from lerobot.utils.hub import HubMixin
-from lerobot.utils.import_utils import _peft_available, require_package
 
 from .utils import log_model_loading_keys
 
-if TYPE_CHECKING or _peft_available:
-    from peft import PEFT_TYPE_TO_CONFIG_MAPPING, PeftType, get_peft_model
-else:
-    PEFT_TYPE_TO_CONFIG_MAPPING = None
-    PeftType = None
-    get_peft_model = None
+T = TypeVar("T", bound="PreTrainedPolicy")
 
 if TYPE_CHECKING:
     from lerobot.datasets.dataset_metadata import LeRobotDatasetMetadata
 
-T = TypeVar("T", bound="PreTrainedPolicy")
-
 
 def _build_card_context(
     cfg: TrainPipelineConfig | None,
@@ -249,10 +241,6 @@ 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]:
@@ -396,7 +384,7 @@ class PreTrainedPolicy(nn.Module, HubMixin, abc.ABC):
             peft_cli_overrides: Optional dict of CLI overrides (method_type, target_modules, r, etc.)
                 These are merged with policy defaults to build the final config.
         """
-        require_package("peft", extra="peft")
+        from peft import get_peft_model
 
         # If user provided a complete config, use it directly (with overrides)
         if peft_config is not None:
@@ -467,7 +455,7 @@ class PreTrainedPolicy(nn.Module, HubMixin, abc.ABC):
         Returns:
             Preprocessed dict with renamed keys and init_type mapped to method-specific key.
         """
-        require_package("peft", extra="peft")
+        from peft import PeftType
 
         cli_overrides = cli_overrides.copy()
 
@@ -492,7 +480,7 @@ class PreTrainedPolicy(nn.Module, HubMixin, abc.ABC):
 
     def _build_peft_config(self, cli_overrides: dict):
         """Build a PEFT config from policy defaults and CLI overrides."""
-        require_package("peft", extra="peft")
+        from peft import PEFT_TYPE_TO_CONFIG_MAPPING, PeftType
 
         # Determine PEFT method type (default to LORA)
         method_type_str = cli_overrides.get("method_type") or "lora"
@@ -519,7 +507,7 @@ class PreTrainedPolicy(nn.Module, HubMixin, abc.ABC):
 
     def _apply_peft_cli_overrides(self, peft_config, cli_overrides: dict):
         """Apply CLI overrides to an existing PEFT config."""
-        require_package("peft", extra="peft")
+        from peft import PEFT_TYPE_TO_CONFIG_MAPPING, PeftType
 
         # Get method type from existing config or CLI override
         method_type_str = cli_overrides.get("method_type")

src/lerobot/policies/smolvla/modeling_smolvla.py

@@ -145,9 +145,6 @@ 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

@@ -168,23 +168,14 @@ class SmolVLMWithExpertModel(nn.Module):
                 last_layers.append(self.num_vlm_layers - 2)
             frozen_layers = [
                 "lm_head",
-                "text_model.norm.weight",
+                "text_model.model.norm.weight",
             ]
             for layer in last_layers:
-                frozen_layers.append(f"text_model.layers.{layer}.")
+                frozen_layers.append(f"text_model.model.layers.{layer}.")
 
-            unmatched_patterns = set(frozen_layers)
             for name, params in self.vlm.named_parameters():
-                matched_patterns = [k for k in frozen_layers if k in name]
-                if matched_patterns:
+                if any(k in name for k in frozen_layers):
                     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.lerobot_types import PolicyAction, RobotAction, RobotObservation
+from 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_prompt" not in name:
+                if "soft_prompts" not in name:
                     param.requires_grad = False
 
         # Freeze or unfreeze soft prompts

src/lerobot/policies/xvla/processor_xvla.py

@@ -21,7 +21,6 @@ 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,
@@ -32,6 +31,7 @@ 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.lerobot_types import (
+from 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.lerobot_types import EnvTransition, PolicyAction
+from 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.lerobot_types import EnvTransition, PolicyAction, RobotAction, RobotObservation, TransitionKey
+from 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.lerobot_types import PolicyAction, RobotAction
+from lerobot.types import PolicyAction, RobotAction
 
 from .pipeline import ActionProcessorStep, ProcessorStepRegistry, RobotActionProcessorStep
 
@@ -132,20 +132,10 @@ class MapDeltaActionToRobotActionStep(RobotActionProcessorStep):
     def transform_features(
         self, features: dict[PipelineFeatureType, dict[str, PolicyFeature]]
     ) -> dict[PipelineFeatureType, dict[str, PolicyFeature]]:
-        for axis in ["x", "y", "z"]:
+        for axis in ["x", "y", "z", "gripper"]:
             features[PipelineFeatureType.ACTION].pop(f"delta_{axis}", None)
-        features[PipelineFeatureType.ACTION].pop("gripper", None)
 
-        for feat in [
-            "enabled",
-            "target_x",
-            "target_y",
-            "target_z",
-            "target_wx",
-            "target_wy",
-            "target_wz",
-            "gripper_vel",
-        ]:
+        for feat in ["enabled", "target_x", "target_y", "target_z", "target_wx", "target_wy", "target_wz"]:
             features[PipelineFeatureType.ACTION][f"{feat}"] = PolicyFeature(
                 type=FeatureType.ACTION, shape=(1,)
             )

src/lerobot/processor/device_processor.py

@@ -25,7 +25,7 @@ from typing import Any
 import torch
 
 from lerobot.configs import PipelineFeatureType, PolicyFeature
-from lerobot.lerobot_types import EnvTransition, PolicyAction, TransitionKey
+from 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.lerobot_types import PolicyAction, RobotAction, RobotObservation
+from 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.lerobot_types import EnvAction, EnvTransition, PolicyAction, TransitionKey
+from 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.lerobot_types import EnvTransition, PolicyAction, TransitionKey
+from 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.lerobot_types import EnvTransition, PolicyAction, TransitionKey
+from lerobot.types import EnvTransition, PolicyAction, TransitionKey
 
 if TYPE_CHECKING:
     from lerobot.datasets import LeRobotDataset

src/lerobot/processor/pipeline.py

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

@@ -25,7 +25,6 @@ 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,
@@ -40,6 +39,7 @@ 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

@@ -47,7 +47,6 @@ 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,
@@ -59,6 +58,7 @@ 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