trim episodes

* add OpenArm Mini config and module init

* add OpenArm Mini teleoperator implementation

* add OpenArm Mini into factory and setup motors

---------

Co-authored-by: Pepijn <138571049+pkooij@users.noreply.github.com>

.github/workflows/full_tests.yml

@@ -173,6 +173,8 @@ jobs:
         shell: bash
         working-directory: /lerobot
     steps:
+      - name: Fix ptxas permissions
+        run: chmod +x /lerobot/.venv/lib/python3.10/site-packages/triton/backends/nvidia/bin/ptxas
       - name: Run pytest on GPU
         run: pytest tests -vv --maxfail=10
       - name: Run end-to-end tests

MANIFEST.in

@@ -1,2 +1,3 @@
 include src/lerobot/templates/lerobot_modelcard_template.md
 include src/lerobot/datasets/card_template.md
+include src/lerobot/envs/metaworld_config.json

docker/Dockerfile.internal

@@ -85,6 +85,8 @@ RUN if [ "$UNBOUND_DEPS" = "true" ]; then \
 
 RUN uv pip install --no-cache ".[all]"
 
+RUN chmod +x /lerobot/.venv/lib/python${PYTHON_VERSION}/site-packages/triton/backends/nvidia/bin/ptxas
+
 # Copy the rest of the application source code
 # Make sure to have the git-LFS files for testing
 COPY --chown=user_lerobot:user_lerobot . .

pyproject.toml

@@ -214,6 +214,9 @@ lerobot-edit-dataset="lerobot.scripts.lerobot_edit_dataset:main"
 lerobot-setup-can="lerobot.scripts.lerobot_setup_can:main"
 
 # ---------------- Tool Configurations ----------------
+[tool.setuptools.package-data]
+lerobot = ["envs/*.json"]
+
 [tool.setuptools.packages.find]
 where = ["src"]
 

src/lerobot/datasets/card_template.md

@@ -7,6 +7,13 @@
 
 This dataset was created using [LeRobot](https://github.com/huggingface/lerobot).
 
+{% if repo_id is defined and repo_id %}
+<a class="flex" href="https://huggingface.co/spaces/lerobot/visualize_dataset?path={{ repo_id }}">
+<img class="block dark:hidden" src="https://huggingface.co/datasets/huggingface/badges/resolve/main/visualize-this-dataset-xl.svg"/>
+<img class="hidden dark:block" src="https://huggingface.co/datasets/huggingface/badges/resolve/main/visualize-this-dataset-xl-dark.svg"/>
+</a>
+{% endif %}
+
 ## Dataset Description
 
 {{ dataset_description | default("", true) }}

src/lerobot/datasets/dataset_tools.py

@@ -47,6 +47,7 @@ from lerobot.datasets.utils import (
     DEFAULT_EPISODES_PATH,
     get_parquet_file_size_in_mb,
     load_episodes,
+    load_info,
     update_chunk_file_indices,
     write_info,
     write_stats,
@@ -567,20 +568,22 @@ def _copy_and_reindex_data(
 def _keep_episodes_from_video_with_av(
     input_path: Path,
     output_path: Path,
-    episodes_to_keep: list[tuple[float, float]],
+    episodes_to_keep: list[tuple[int, int]],
     fps: float,
     vcodec: str = "libsvtav1",
     pix_fmt: str = "yuv420p",
 ) -> None:
     """Keep only specified episodes from a video file using PyAV.
 
-    This function decodes frames from specified time ranges and re-encodes them with
+    This function decodes frames from specified frame ranges and re-encodes them with
     properly reset timestamps to ensure monotonic progression.
 
     Args:
         input_path: Source video file path.
         output_path: Destination video file path.
-        episodes_to_keep: List of (start_time, end_time) tuples for episodes to keep.
+        episodes_to_keep: List of (start_frame, end_frame) tuples for episodes to keep.
+            Ranges are half-open intervals: [start_frame, end_frame), where start_frame
+            is inclusive and end_frame is exclusive.
         fps: Frame rate of the video.
         vcodec: Video codec to use for encoding.
         pix_fmt: Pixel format for output video.
@@ -622,9 +625,10 @@ def _keep_episodes_from_video_with_av(
 
     # Create set of (start, end) ranges for fast lookup.
     # Convert to a sorted list for efficient checking.
-    time_ranges = sorted(episodes_to_keep)
+    frame_ranges = sorted(episodes_to_keep)
 
     # Track frame index for setting PTS and current range being processed.
+    src_frame_count = 0
     frame_count = 0
     range_idx = 0
 
@@ -634,21 +638,20 @@ def _keep_episodes_from_video_with_av(
             if frame is None:
                 continue
 
-            # Get frame timestamp.
-            frame_time = float(frame.pts * frame.time_base) if frame.pts is not None else 0.0
-
-            # Check if frame is in any of our desired time ranges.
+            # Check if frame is in any of our desired frame ranges.
             # Skip ranges that have already passed.
-            while range_idx < len(time_ranges) and frame_time >= time_ranges[range_idx][1]:
+            while range_idx < len(frame_ranges) and src_frame_count >= frame_ranges[range_idx][1]:
                 range_idx += 1
 
             # If we've passed all ranges, stop processing.
-            if range_idx >= len(time_ranges):
+            if range_idx >= len(frame_ranges):
                 break
 
             # Check if frame is in current range.
-            start_ts, end_ts = time_ranges[range_idx]
-            if frame_time < start_ts:
+            start_frame = frame_ranges[range_idx][0]
+
+            if src_frame_count < start_frame:
+                src_frame_count += 1
                 continue
 
             # Frame is in range - create a new frame with reset timestamps.
@@ -661,6 +664,7 @@ def _keep_episodes_from_video_with_av(
             for pkt in v_out.encode(new_frame):
                 out.mux(pkt)
 
+            src_frame_count += 1
             frame_count += 1
 
     # Flush encoder.
@@ -749,15 +753,17 @@ def _copy_and_reindex_videos(
                         f"videos/{video_key}/to_timestamp"
                     ]
             else:
-                # Build list of time ranges to keep, in sorted order.
+                # Build list of frame ranges to keep, in sorted order.
                 sorted_keep_episodes = sorted(episodes_in_file, key=lambda x: episode_mapping[x])
-                episodes_to_keep_ranges: list[tuple[float, float]] = []
-
+                episodes_to_keep_ranges: list[tuple[int, int]] = []
                 for old_idx in sorted_keep_episodes:
                     src_ep = src_dataset.meta.episodes[old_idx]
-                    from_ts = src_ep[f"videos/{video_key}/from_timestamp"]
-                    to_ts = src_ep[f"videos/{video_key}/to_timestamp"]
-                    episodes_to_keep_ranges.append((from_ts, to_ts))
+                    from_frame = round(src_ep[f"videos/{video_key}/from_timestamp"] * src_dataset.meta.fps)
+                    to_frame = round(src_ep[f"videos/{video_key}/to_timestamp"] * src_dataset.meta.fps)
+                    assert src_ep["length"] == to_frame - from_frame, (
+                        f"Episode length mismatch: {src_ep['length']} vs {to_frame - from_frame}"
+                    )
+                    episodes_to_keep_ranges.append((from_frame, to_frame))
 
                 # Use PyAV filters to efficiently re-encode only the desired segments.
                 assert src_dataset.meta.video_path is not None
@@ -1769,3 +1775,296 @@ def convert_image_to_video_dataset(
 
     # Return new dataset
     return LeRobotDataset(repo_id=repo_id, root=output_dir)
+
+
+def trim_episodes_by_frames(
+    dataset: LeRobotDataset,
+    episode_frames_to_keep: dict[int, list[int]],
+    output_dir: str | Path | None = None,
+    repo_id: str | None = None,
+) -> LeRobotDataset:
+    """Trim multiple episodes to keep only specific frames.
+
+    This function creates a new dataset where the specified episodes contain only
+    the frames at the given indices. All other episodes are copied as-is.
+
+    Args:
+        dataset: The source LeRobotDataset.
+        episode_frames_to_keep: Dict mapping episode indices to lists of global frame indices to keep.
+        output_dir: Directory to save the new dataset. If None, uses default location.
+        repo_id: Repository ID for the new dataset. If None, appends "_trimmed" to original.
+
+    Returns:
+        A new LeRobotDataset with the trimmed episodes.
+    """
+    if not episode_frames_to_keep:
+        raise ValueError("No episodes to trim")
+
+    for ep_idx in episode_frames_to_keep:
+        if ep_idx >= dataset.meta.total_episodes:
+            raise ValueError(f"Episode {ep_idx} does not exist")
+        if not episode_frames_to_keep[ep_idx]:
+            raise ValueError(f"No frames to keep for episode {ep_idx}")
+
+    if repo_id is None:
+        repo_id = f"{dataset.repo_id}_trimmed"
+    output_dir = Path(output_dir) if output_dir is not None else HF_LEROBOT_HOME / repo_id
+
+    total_trimmed = sum(len(frames) for frames in episode_frames_to_keep.values())
+    logging.info(f"Trimming {len(episode_frames_to_keep)} episodes, keeping {total_trimmed} frames total")
+
+    # Create new metadata
+    new_meta = LeRobotDatasetMetadata.create(
+        repo_id=repo_id,
+        fps=dataset.meta.fps,
+        features=dataset.meta.features,
+        robot_type=dataset.meta.robot_type,
+        root=output_dir,
+        use_videos=len(dataset.meta.video_keys) > 0,
+    )
+
+    # Build set of all frames to keep (for episodes being trimmed)
+    # and compute new frame counts per episode
+    all_keep_frames: set[int] = set()
+    trimmed_frame_counts: dict[int, int] = {}
+    for ep_idx, frames in episode_frames_to_keep.items():
+        all_keep_frames.update(frames)
+        trimmed_frame_counts[ep_idx] = len(frames)
+
+    # Copy and filter data
+    _copy_and_reindex_data_with_multi_frame_filter(
+        dataset, new_meta, episode_frames_to_keep, all_keep_frames
+    )
+
+    # Handle videos if present
+    if dataset.meta.video_keys:
+        _copy_and_reindex_videos_with_multi_frame_filter(
+            dataset, new_meta, episode_frames_to_keep
+        )
+
+    # Copy episode metadata
+    _copy_and_reindex_episodes_metadata_for_multi_trim(
+        dataset, new_meta, trimmed_frame_counts
+    )
+
+    logging.info(f"Created trimmed dataset with {new_meta.total_frames} frames at {output_dir}")
+    
+    # Return the metadata instead of trying to load as LeRobotDataset
+    # This avoids Hub validation issues when the repo doesn't exist yet
+    return new_meta
+
+
+# Keep old function for backward compatibility
+def trim_episode_by_frames(
+    dataset: LeRobotDataset,
+    episode_index: int,
+    keep_frame_indices: list[int],
+    output_dir: str | Path | None = None,
+    repo_id: str | None = None,
+) -> LeRobotDataset:
+    """Trim a single episode. Wrapper around trim_episodes_by_frames."""
+    return trim_episodes_by_frames(
+        dataset,
+        episode_frames_to_keep={episode_index: keep_frame_indices},
+        output_dir=output_dir,
+        repo_id=repo_id,
+    )
+
+
+def _copy_and_reindex_data_with_multi_frame_filter(
+    src_dataset: LeRobotDataset,
+    dst_meta: LeRobotDatasetMetadata,
+    episode_frames_to_keep: dict[int, list[int]],
+    all_keep_frames: set[int],
+) -> None:
+    """Copy data files with frame-level filtering for multiple episodes."""
+    if src_dataset.meta.episodes is None:
+        src_dataset.meta.episodes = load_episodes(src_dataset.meta.root)
+
+    # Copy tasks
+    if dst_meta.tasks is None and src_dataset.meta.tasks is not None:
+        # Tasks are stored with task string as index
+        dst_meta.save_episode_tasks(list(src_dataset.meta.tasks.index))
+
+    # Get all parquet files
+    data_dir = src_dataset.root / "data"
+    parquet_files = sorted(data_dir.glob("chunk-*/file-*.parquet"))
+
+    trim_episode_set = set(episode_frames_to_keep.keys())
+    global_index = 0
+
+    for parquet_path in tqdm(parquet_files, desc="Processing data files"):
+        df = pd.read_parquet(parquet_path)
+
+        # Filter: keep all frames from non-trimmed episodes, 
+        # and only specified frames from trimmed episodes
+        mask = (~df["episode_index"].isin(trim_episode_set)) | (df["index"].isin(all_keep_frames))
+        df = df[mask].copy().reset_index(drop=True)
+
+        if len(df) == 0:
+            continue
+
+        # Reindex
+        df["index"] = range(global_index, global_index + len(df))
+
+        # Recalculate frame_index within each episode
+        for ep_idx in df["episode_index"].unique():
+            ep_mask = df["episode_index"] == ep_idx
+            df.loc[ep_mask, "frame_index"] = range(ep_mask.sum())
+
+        # Recalculate timestamps based on frame_index and fps
+        df["timestamp"] = df["frame_index"] / src_dataset.meta.fps
+
+        # Determine output path (keep same structure)
+        rel_path = parquet_path.relative_to(src_dataset.root)
+        dst_path = dst_meta.root / rel_path
+        dst_path.parent.mkdir(parents=True, exist_ok=True)
+
+        _write_parquet(df, dst_path, dst_meta)
+        global_index += len(df)
+
+
+def _copy_and_reindex_videos_with_multi_frame_filter(
+    src_dataset: LeRobotDataset,
+    dst_meta: LeRobotDatasetMetadata,
+    episode_frames_to_keep: dict[int, list[int]],
+) -> None:
+    """Copy video files for trimmed dataset.
+    
+    In v3.0 datasets, multiple episodes are concatenated into single video files.
+    Each episode has from_timestamp/to_timestamp indicating its portion of the video.
+    
+    For trimming, we copy the original video files as-is and update the metadata
+    timestamps in _copy_and_reindex_episodes_metadata_for_multi_trim.
+    """
+    for video_key in src_dataset.meta.video_keys:
+        video_dir = src_dataset.root / "videos" / video_key
+        dst_video_dir = dst_meta.root / "videos" / video_key
+        
+        if not video_dir.exists():
+            logging.warning(f"Video directory not found: {video_dir}")
+            continue
+        
+        # Copy all video files (they contain concatenated episodes)
+        # The metadata timestamps will handle which portions to use
+        copied_files = set()
+        for chunk_dir in video_dir.glob("chunk-*"):
+            dst_chunk_dir = dst_video_dir / chunk_dir.name
+            dst_chunk_dir.mkdir(parents=True, exist_ok=True)
+            
+            for video_file in chunk_dir.glob("*.mp4"):
+                if video_file.name not in copied_files:
+                    dst_path = dst_chunk_dir / video_file.name
+                    if not dst_path.exists():
+                        shutil.copy(video_file, dst_path)
+                        copied_files.add(video_file.name)
+        
+        logging.info(f"Copied {len(copied_files)} video files for {video_key}")
+
+
+def _trim_video_frames(
+    src_path: Path,
+    dst_path: Path,
+    keep_frame_indices: list[int],
+    fps: float,
+    episode_start_idx: int,
+) -> None:
+    """Trim a video to keep only specific frames using ffmpeg."""
+    import subprocess
+
+    # Convert global indices to local indices within the episode
+    local_indices = sorted([idx - episode_start_idx for idx in keep_frame_indices])
+
+    if not local_indices:
+        logging.warning(f"No frames to keep for video {src_path}")
+        return
+
+    # Calculate start and end times
+    start_frame = local_indices[0]
+    end_frame = local_indices[-1]
+
+    start_time = start_frame / fps
+    duration = (end_frame - start_frame + 1) / fps
+
+    # Use ffmpeg to trim
+    cmd = [
+        "ffmpeg", "-y",
+        "-ss", str(start_time),
+        "-i", str(src_path),
+        "-t", str(duration),
+        "-c", "copy",  # Fast copy without re-encoding
+        str(dst_path)
+    ]
+
+    try:
+        subprocess.run(cmd, check=True, capture_output=True)
+    except subprocess.CalledProcessError as e:
+        logging.error(f"Failed to trim video: {e.stderr.decode()}")
+        # Fallback: copy the whole video
+        shutil.copy(src_path, dst_path)
+
+
+def _copy_and_reindex_episodes_metadata_for_multi_trim(
+    src_dataset: LeRobotDataset,
+    dst_meta: LeRobotDatasetMetadata,
+    trimmed_frame_counts: dict[int, int],
+) -> None:
+    """Copy and update episode metadata for trimmed dataset."""
+    if src_dataset.meta.episodes is None:
+        src_dataset.meta.episodes = load_episodes(src_dataset.meta.root)
+
+    # Calculate new frame counts and indices
+    episodes_data = []
+    global_idx = 0
+
+    for old_ep_idx in range(src_dataset.meta.total_episodes):
+        src_ep = src_dataset.meta.episodes[old_ep_idx]
+
+        if old_ep_idx in trimmed_frame_counts:
+            ep_length = trimmed_frame_counts[old_ep_idx]
+        else:
+            ep_length = src_ep["length"]
+
+        ep_data = {
+            "episode_index": old_ep_idx,
+            "tasks": src_ep["tasks"],
+            "length": ep_length,
+            "data/chunk_index": src_ep["data/chunk_index"],
+            "data/file_index": src_ep["data/file_index"],
+            "dataset_from_index": global_idx,
+            "dataset_to_index": global_idx + ep_length,
+        }
+
+        # Copy video metadata - preserve timestamps for concatenated videos
+        for video_key in src_dataset.meta.video_keys:
+            ep_data[f"videos/{video_key}/chunk_index"] = src_ep[f"videos/{video_key}/chunk_index"]
+            ep_data[f"videos/{video_key}/file_index"] = src_ep[f"videos/{video_key}/file_index"]
+            
+            # Keep original from_timestamp (start position in concatenated video)
+            orig_from_ts = src_ep[f"videos/{video_key}/from_timestamp"]
+            ep_data[f"videos/{video_key}/from_timestamp"] = orig_from_ts
+            
+            # For trimmed episodes, update to_timestamp based on new length
+            # For non-trimmed episodes, keep original to_timestamp
+            if old_ep_idx in trimmed_frame_counts:
+                ep_data[f"videos/{video_key}/to_timestamp"] = orig_from_ts + (ep_length / src_dataset.meta.fps)
+            else:
+                ep_data[f"videos/{video_key}/to_timestamp"] = src_ep[f"videos/{video_key}/to_timestamp"]
+
+        ep_data["meta/episodes/chunk_index"] = 0
+        ep_data["meta/episodes/file_index"] = 0
+
+        episodes_data.append(ep_data)
+        global_idx += ep_length
+
+    # Save episodes metadata
+    df = pd.DataFrame(episodes_data)
+    episodes_path = dst_meta.root / DEFAULT_EPISODES_PATH.format(chunk_index=0, file_index=0)
+    episodes_path.parent.mkdir(parents=True, exist_ok=True)
+    df.to_parquet(episodes_path)
+
+    # Update info.json
+    info = load_info(src_dataset.root)
+    info["total_episodes"] = len(episodes_data)
+    info["total_frames"] = global_idx
+    write_info(info, dst_meta.root)

src/lerobot/datasets/lerobot_dataset.py

@@ -747,7 +747,7 @@ class LeRobotDataset(torch.utils.data.Dataset):
             # Check if cached dataset contains all requested episodes
             if not self._check_cached_episodes_sufficient():
                 raise FileNotFoundError("Cached dataset doesn't contain all requested episodes")
-        except (AssertionError, FileNotFoundError, NotADirectoryError):
+        except (FileNotFoundError, NotADirectoryError):
             if is_valid_version(self.revision):
                 self.revision = get_safe_version(self.repo_id, self.revision)
             self.download(download_videos)
@@ -839,7 +839,7 @@ class LeRobotDataset(torch.utils.data.Dataset):
             hub_api.upload_folder(**upload_kwargs)
 
         card = create_lerobot_dataset_card(
-            tags=tags, dataset_info=self.meta.info, license=license, **card_kwargs
+            tags=tags, dataset_info=self.meta.info, license=license, repo_id=self.repo_id, **card_kwargs
         )
         card.push_to_hub(repo_id=self.repo_id, repo_type="dataset", revision=branch)
 

src/lerobot/datasets/video_utils.py

@@ -227,16 +227,17 @@ def decode_video_frames_torchvision(
     min_, argmin_ = dist.min(1)
 
     is_within_tol = min_ < tolerance_s
-    assert is_within_tol.all(), (
-        f"One or several query timestamps unexpectedly violate the tolerance ({min_[~is_within_tol]} > {tolerance_s=})."
-        "It means that the closest frame that can be loaded from the video is too far away in time."
-        "This might be due to synchronization issues with timestamps during data collection."
-        "To be safe, we advise to ignore this item during training."
-        f"\nqueried timestamps: {query_ts}"
-        f"\nloaded timestamps: {loaded_ts}"
-        f"\nvideo: {video_path}"
-        f"\nbackend: {backend}"
-    )
+    if not is_within_tol.all():
+        raise FrameTimestampError(
+            f"One or several query timestamps unexpectedly violate the tolerance ({min_[~is_within_tol]} > {tolerance_s=})."
+            " It means that the closest frame that can be loaded from the video is too far away in time."
+            " This might be due to synchronization issues with timestamps during data collection."
+            " To be safe, we advise to ignore this item during training."
+            f"\nqueried timestamps: {query_ts}"
+            f"\nloaded timestamps: {loaded_ts}"
+            f"\nvideo: {video_path}"
+            f"\nbackend: {backend}"
+        )
 
     # get closest frames to the query timestamps
     closest_frames = torch.stack([loaded_frames[idx] for idx in argmin_])
@@ -248,7 +249,11 @@ def decode_video_frames_torchvision(
     # convert to the pytorch format which is float32 in [0,1] range (and channel first)
     closest_frames = closest_frames.type(torch.float32) / 255
 
-    assert len(timestamps) == len(closest_frames)
+    if len(timestamps) != len(closest_frames):
+        raise FrameTimestampError(
+            f"Number of retrieved frames ({len(closest_frames)}) does not match "
+            f"number of queried timestamps ({len(timestamps)})"
+        )
     return closest_frames
 
 
@@ -353,15 +358,16 @@ def decode_video_frames_torchcodec(
     min_, argmin_ = dist.min(1)
 
     is_within_tol = min_ < tolerance_s
-    assert is_within_tol.all(), (
-        f"One or several query timestamps unexpectedly violate the tolerance ({min_[~is_within_tol]} > {tolerance_s=})."
-        "It means that the closest frame that can be loaded from the video is too far away in time."
-        "This might be due to synchronization issues with timestamps during data collection."
-        "To be safe, we advise to ignore this item during training."
-        f"\nqueried timestamps: {query_ts}"
-        f"\nloaded timestamps: {loaded_ts}"
-        f"\nvideo: {video_path}"
-    )
+    if not is_within_tol.all():
+        raise FrameTimestampError(
+            f"One or several query timestamps unexpectedly violate the tolerance ({min_[~is_within_tol]} > {tolerance_s=})."
+            " It means that the closest frame that can be loaded from the video is too far away in time."
+            " This might be due to synchronization issues with timestamps during data collection."
+            " To be safe, we advise to ignore this item during training."
+            f"\nqueried timestamps: {query_ts}"
+            f"\nloaded timestamps: {loaded_ts}"
+            f"\nvideo: {video_path}"
+        )
 
     # get closest frames to the query timestamps
     closest_frames = torch.stack([loaded_frames[idx] for idx in argmin_])

src/lerobot/policies/diffusion/configuration_diffusion.py

@@ -139,6 +139,10 @@ class DiffusionConfig(PreTrainedConfig):
     # Inference
     num_inference_steps: int | None = None
 
+    # Optimization
+    compile_model: bool = False
+    compile_mode: str = "reduce-overhead"
+
     # Loss computation
     do_mask_loss_for_padding: bool = False
 

src/lerobot/policies/diffusion/modeling_diffusion.py

@@ -142,6 +142,9 @@ class DiffusionPolicy(PreTrainedPolicy):
         """Run the batch through the model and compute the loss for training or validation."""
         if self.config.image_features:
             batch = dict(batch)  # shallow copy so that adding a key doesn't modify the original
+            for key in self.config.image_features:
+                if self.config.n_obs_steps == 1 and batch[key].ndim == 4:
+                    batch[key] = batch[key].unsqueeze(1)
             batch[OBS_IMAGES] = torch.stack([batch[key] for key in self.config.image_features], dim=-4)
         loss = self.diffusion.compute_loss(batch)
         # no output_dict so returning None
@@ -182,6 +185,11 @@ class DiffusionModel(nn.Module):
 
         self.unet = DiffusionConditionalUnet1d(config, global_cond_dim=global_cond_dim * config.n_obs_steps)
 
+        if config.compile_model:
+            # Compile the U-Net. "reduce-overhead" is preferred for the small-batch repetitive loops
+            # common in diffusion inference.
+            self.unet = torch.compile(self.unet, mode=config.compile_mode)
+
         self.noise_scheduler = _make_noise_scheduler(
             config.noise_scheduler_type,
             num_train_timesteps=config.num_train_timesteps,

src/lerobot/policies/sarm/processor_sarm.py

@@ -277,9 +277,7 @@ class SARMEncodingProcessorStep(ProcessorStep):
 
         # When language is perturbed, targets are zero so perturbed samples don't contribute to progress loss
         if self.dataset_meta is not None:
-            episodes_df = None
-            if self.sparse_subtask_names != ["task"]:
-                episodes_df = self.dataset_meta.episodes.to_pandas()
+            episodes_df = self.dataset_meta.episodes.to_pandas()
 
             # Generate sparse targets
             if self.sparse_temporal_proportions is not None:

src/lerobot/scripts/lerobot_edit_dataset.py

@@ -104,6 +104,28 @@ Convert image dataset to video format and push to hub:
         --operation.type convert_image_to_video \
         --push_to_hub true
 
+Trim single episode to keep only frames within timestamp range:
+    python -m lerobot.scripts.lerobot_edit_dataset \
+        --repo_id lerobot/pusht \
+        --new_repo_id lerobot/pusht_trimmed \
+        --operation.type trim_episode \
+        --operation.episode_index 0 \
+        --operation.start_timestamp 10.0 \
+        --operation.end_timestamp 30.0
+
+Trim multiple episodes at once (use null for no limit):
+    python -m lerobot.scripts.lerobot_edit_dataset \
+        --repo_id lerobot/pusht \
+        --operation.type trim_episode \
+        --operation.episode_trims '{"0": [10.0, 30.0], "2": [5.0, null], "3": [null, 20.0]}'
+
+Trim and re-upload to same repo (overwrites original):
+    python -m lerobot.scripts.lerobot_edit_dataset \
+        --repo_id lerobot/pusht \
+        --operation.type trim_episode \
+        --operation.episode_index 0 \
+        --operation.start_timestamp 10.0 \
+        --push_to_hub true
 Show dataset information:
     lerobot-edit-dataset \
         --repo_id lerobot/pusht_image \
@@ -204,9 +226,32 @@ class InfoConfig(OperationConfig):
     show_features: bool = False
 
 
+@dataclass
+class TrimEpisodeConfig:
+    """Trim episodes to keep only frames within timestamp ranges.
+    
+    Supports multiple episodes via episode_trims dict:
+        --operation.episode_trims '{"0": [10.0, 30.0], "2": [5.0, 20.0]}'
+    
+    Or single episode via legacy parameters:
+        --operation.episode_index 0 --operation.start_timestamp 10.0 --operation.end_timestamp 30.0
+    """
+    type: str = "trim_episode"
+    # Multi-episode support: dict mapping episode_index -> [start_timestamp, end_timestamp]
+    # Use null for no limit, e.g. {"0": [10.0, null], "2": [null, 30.0]}
+    episode_trims: dict[str, list[float | None]] | None = None
+    # Legacy single-episode parameters (used if episode_trims is None)
+    episode_index: int | None = None
+    start_timestamp: float | None = None  # Keep frames from this timestamp (inclusive)
+    end_timestamp: float | None = None    # Keep frames until this timestamp (inclusive)
+
+
 @dataclass
 class EditDatasetConfig:
     repo_id: str
+    operation: (
+        DeleteEpisodesConfig | SplitConfig | MergeConfig | RemoveFeatureConfig | ConvertImageToVideoConfig | TrimEpisodeConfig
+    )
     operation: OperationConfig
     root: str | None = None
     new_repo_id: str | None = None
@@ -351,6 +396,92 @@ def handle_remove_feature(cfg: EditDatasetConfig) -> None:
         LeRobotDataset(output_repo_id, root=output_dir).push_to_hub()
 
 
+def handle_trim_episode(cfg: EditDatasetConfig) -> None:
+    """Trim episodes to keep only frames within timestamp ranges."""
+    if not isinstance(cfg.operation, TrimEpisodeConfig):
+        raise ValueError("Operation config must be TrimEpisodeConfig")
+
+    # Parse episode trims - support both multi-episode dict and legacy single episode
+    episode_trims: dict[int, tuple[float | None, float | None]] = {}
+    
+    if cfg.operation.episode_trims is not None:
+        # Multi-episode mode
+        for ep_str, ts_range in cfg.operation.episode_trims.items():
+            ep_idx = int(ep_str)
+            start_ts = ts_range[0] if len(ts_range) > 0 else None
+            end_ts = ts_range[1] if len(ts_range) > 1 else None
+            episode_trims[ep_idx] = (start_ts, end_ts)
+    elif cfg.operation.episode_index is not None:
+        # Legacy single-episode mode
+        if cfg.operation.start_timestamp is None and cfg.operation.end_timestamp is None:
+            raise ValueError("At least one of start_timestamp or end_timestamp must be specified")
+        episode_trims[cfg.operation.episode_index] = (
+            cfg.operation.start_timestamp,
+            cfg.operation.end_timestamp,
+        )
+    else:
+        raise ValueError("Either episode_trims or episode_index must be specified")
+
+    dataset = LeRobotDataset(cfg.repo_id, root=cfg.root)
+    output_repo_id, output_dir = get_output_path(
+        cfg.repo_id, cfg.new_repo_id, Path(cfg.root) if cfg.root else None
+    )
+
+    if cfg.new_repo_id is None:
+        dataset.root = Path(str(dataset.root) + "_old")
+
+    logging.info(f"Trimming {len(episode_trims)} episode(s) from {cfg.repo_id}")
+
+    # Get episode boundaries and find frames to keep for each episode
+    episodes_info = dataset.meta.episodes
+    all_frames_to_keep: dict[int, list[int]] = {}
+    
+    for ep_idx, (start_ts, end_ts) in episode_trims.items():
+        if ep_idx >= len(episodes_info["episode_index"]):
+            raise ValueError(f"Episode {ep_idx} does not exist (dataset has {len(episodes_info['episode_index'])} episodes)")
+
+        from_frame = episodes_info["dataset_from_index"][ep_idx]
+        to_frame = episodes_info["dataset_to_index"][ep_idx]
+        
+        logging.info(f"Episode {ep_idx}: trimming to [{start_ts}, {end_ts}]")
+        logging.info(f"  Original frames: {from_frame} to {to_frame} ({to_frame - from_frame} frames)")
+
+        # Find frames within timestamp range
+        frames_to_keep = []
+        for frame_idx in range(from_frame, to_frame):
+            frame = dataset.hf_dataset[frame_idx]
+            ts = frame["timestamp"]
+            
+            in_range = True
+            if start_ts is not None and ts < start_ts:
+                in_range = False
+            if end_ts is not None and ts > end_ts:
+                in_range = False
+            
+            if in_range:
+                frames_to_keep.append(frame_idx)
+
+        if not frames_to_keep:
+            raise ValueError(f"Episode {ep_idx}: No frames found in timestamp range [{start_ts}, {end_ts}]")
+
+        logging.info(f"  Keeping {len(frames_to_keep)} frames (indices {frames_to_keep[0]} to {frames_to_keep[-1]})")
+        all_frames_to_keep[ep_idx] = frames_to_keep
+
+    from lerobot.datasets.dataset_tools import trim_episodes_by_frames
+    
+    new_dataset = trim_episodes_by_frames(
+        dataset,
+        episode_frames_to_keep=all_frames_to_keep,
+        output_dir=output_dir,
+        repo_id=output_repo_id,
+    )
+
+    logging.info(f"Dataset saved to {output_dir}")
+    logging.info(f"Episodes: {new_dataset.meta.total_episodes}, Frames: {new_dataset.meta.total_frames}")
+
+    if cfg.push_to_hub:
+        logging.info(f"Pushing to hub as {output_repo_id}")
+        LeRobotDataset(output_repo_id, root=output_dir).push_to_hub()
 def handle_modify_tasks(cfg: EditDatasetConfig) -> None:
     if not isinstance(cfg.operation, ModifyTasksConfig):
         raise ValueError("Operation config must be ModifyTasksConfig")
@@ -515,6 +646,8 @@ def edit_dataset(cfg: EditDatasetConfig) -> None:
         handle_modify_tasks(cfg)
     elif operation_type == "convert_image_to_video":
         handle_convert_image_to_video(cfg)
+    elif operation_type == "trim_episode":
+        handle_trim_episode(cfg)
     elif operation_type == "info":
         handle_info(cfg)
     else:

src/lerobot/scripts/lerobot_setup_motors.py

@@ -43,6 +43,7 @@ from lerobot.teleoperators import (  # noqa: F401
     koch_leader,
     make_teleoperator_from_config,
     omx_leader,
+    openarm_mini,
     so_leader,
 )
 
@@ -51,6 +52,7 @@ COMPATIBLE_DEVICES = [
     "koch_leader",
     "omx_follower",
     "omx_leader",
+    "openarm_mini",
     "so100_follower",
     "so100_leader",
     "so101_follower",

src/lerobot/scripts/lerobot_train.py

@@ -24,6 +24,7 @@ import torch
 from accelerate import Accelerator
 from termcolor import colored
 from torch.optim import Optimizer
+from tqdm import tqdm
 
 from lerobot.configs import parser
 from lerobot.configs.train import TrainPipelineConfig
@@ -51,6 +52,7 @@ from lerobot.utils.utils import (
     format_big_number,
     has_method,
     init_logging,
+    inside_slurm,
 )
 
 
@@ -390,6 +392,14 @@ def train(cfg: TrainPipelineConfig, accelerator: Accelerator | None = None):
     )
 
     if is_main_process:
+        progbar = tqdm(
+            total=cfg.steps - step,
+            desc="Training",
+            unit="step",
+            disable=inside_slurm(),
+            position=0,
+            leave=True,
+        )
         logging.info(
             f"Start offline training on a fixed dataset, with effective batch size: {effective_batch_size}"
         )
@@ -414,6 +424,8 @@ def train(cfg: TrainPipelineConfig, accelerator: Accelerator | None = None):
         # Note: eval and checkpoint happens *after* the `step`th training update has completed, so we
         # increment `step` here.
         step += 1
+        if is_main_process:
+            progbar.update(1)
         train_tracker.step()
         is_log_step = cfg.log_freq > 0 and step % cfg.log_freq == 0 and is_main_process
         is_saving_step = step % cfg.save_freq == 0 or step == cfg.steps
@@ -507,6 +519,9 @@ def train(cfg: TrainPipelineConfig, accelerator: Accelerator | None = None):
 
             accelerator.wait_for_everyone()
 
+    if is_main_process:
+        progbar.close()
+
     if eval_env:
         close_envs(eval_env)
 

src/lerobot/teleoperators/openarm_mini/__init__.py

@@ -0,0 +1,20 @@
+#!/usr/bin/env python
+
+# Copyright 2025 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
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from .config_openarm_mini import OpenArmMiniConfig
+from .openarm_mini import OpenArmMini
+
+__all__ = ["OpenArmMini", "OpenArmMiniConfig"]

src/lerobot/teleoperators/openarm_mini/config_openarm_mini.py

@@ -0,0 +1,30 @@
+#!/usr/bin/env python
+
+# Copyright 2025 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
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from dataclasses import dataclass
+
+from ..config import TeleoperatorConfig
+
+
+@TeleoperatorConfig.register_subclass("openarm_mini")
+@dataclass
+class OpenArmMiniConfig(TeleoperatorConfig):
+    """Configuration for OpenArm Mini teleoperator with Feetech motors (dual arms)."""
+
+    port_right: str = "/dev/ttyUSB0"
+    port_left: str = "/dev/ttyUSB1"
+
+    use_degrees: bool = True

src/lerobot/teleoperators/openarm_mini/openarm_mini.py

@@ -0,0 +1,296 @@
+#!/usr/bin/env python
+
+# Copyright 2025 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
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import logging
+import time
+from typing import Any
+
+from lerobot.motors import Motor, MotorCalibration, MotorNormMode
+from lerobot.motors.feetech import (
+    FeetechMotorsBus,
+    OperatingMode,
+)
+from lerobot.processor import RobotAction
+from lerobot.utils.decorators import check_if_already_connected, check_if_not_connected
+
+from ..teleoperator import Teleoperator
+from .config_openarm_mini import OpenArmMiniConfig
+
+logger = logging.getLogger(__name__)
+
+# Motors whose direction is inverted during readout
+RIGHT_MOTORS_TO_FLIP = ["joint_1", "joint_2", "joint_3", "joint_4", "joint_5"]
+LEFT_MOTORS_TO_FLIP = ["joint_1", "joint_3", "joint_4", "joint_5", "joint_6", "joint_7"]
+
+
+class OpenArmMini(Teleoperator):
+    """
+    OpenArm Mini Teleoperator with dual Feetech-based arms (8 motors per arm).
+
+    Each arm has 7 joints plus a gripper, using Feetech STS3215 servos.
+    """
+
+    config_class = OpenArmMiniConfig
+    name = "openarm_mini"
+
+    def __init__(self, config: OpenArmMiniConfig):
+        super().__init__(config)
+        self.config = config
+
+        norm_mode_body = MotorNormMode.DEGREES
+
+        motors_right = {
+            "joint_1": Motor(1, "sts3215", norm_mode_body),
+            "joint_2": Motor(2, "sts3215", norm_mode_body),
+            "joint_3": Motor(3, "sts3215", norm_mode_body),
+            "joint_4": Motor(4, "sts3215", norm_mode_body),
+            "joint_5": Motor(5, "sts3215", norm_mode_body),
+            "joint_6": Motor(6, "sts3215", norm_mode_body),
+            "joint_7": Motor(7, "sts3215", norm_mode_body),
+            "gripper": Motor(8, "sts3215", MotorNormMode.RANGE_0_100),
+        }
+
+        motors_left = {
+            "joint_1": Motor(1, "sts3215", norm_mode_body),
+            "joint_2": Motor(2, "sts3215", norm_mode_body),
+            "joint_3": Motor(3, "sts3215", norm_mode_body),
+            "joint_4": Motor(4, "sts3215", norm_mode_body),
+            "joint_5": Motor(5, "sts3215", norm_mode_body),
+            "joint_6": Motor(6, "sts3215", norm_mode_body),
+            "joint_7": Motor(7, "sts3215", norm_mode_body),
+            "gripper": Motor(8, "sts3215", MotorNormMode.RANGE_0_100),
+        }
+
+        cal_right = {
+            k.replace("right_", ""): v for k, v in (self.calibration or {}).items() if k.startswith("right_")
+        }
+        cal_left = {
+            k.replace("left_", ""): v for k, v in (self.calibration or {}).items() if k.startswith("left_")
+        }
+
+        self.bus_right = FeetechMotorsBus(
+            port=self.config.port_right,
+            motors=motors_right,
+            calibration=cal_right,
+        )
+
+        self.bus_left = FeetechMotorsBus(
+            port=self.config.port_left,
+            motors=motors_left,
+            calibration=cal_left,
+        )
+
+    @property
+    def action_features(self) -> dict[str, type]:
+        features: dict[str, type] = {}
+        for motor in self.bus_right.motors:
+            features[f"right_{motor}.pos"] = float
+        for motor in self.bus_left.motors:
+            features[f"left_{motor}.pos"] = float
+        return features
+
+    @property
+    def feedback_features(self) -> dict[str, type]:
+        return {}
+
+    @property
+    def is_connected(self) -> bool:
+        return self.bus_right.is_connected and self.bus_left.is_connected
+
+    @check_if_already_connected
+    def connect(self, calibrate: bool = True) -> None:
+        logger.info(f"Connecting right arm on {self.config.port_right}...")
+        self.bus_right.connect()
+        logger.info(f"Connecting left arm on {self.config.port_left}...")
+        self.bus_left.connect()
+
+        if calibrate:
+            self.calibrate()
+
+        self.configure()
+        logger.info(f"{self} connected.")
+
+    @property
+    def is_calibrated(self) -> bool:
+        return self.bus_right.is_calibrated and self.bus_left.is_calibrated
+
+    def calibrate(self) -> None:
+        """
+        Run calibration procedure for OpenArm Mini.
+
+        1. Disable torque
+        2. Ask user to position arms in hanging position with grippers closed
+        3. Set this as zero position via half-turn homing
+        4. Interactive gripper calibration (open/close positions)
+        5. Save calibration
+        """
+        if self.calibration:
+            user_input = input(
+                f"Press ENTER to use existing calibration for {self.id}, "
+                f"or type 'c' and press ENTER to run new calibration: "
+            )
+            if user_input.strip().lower() != "c":
+                logger.info(f"Using existing calibration for {self.id}")
+                cal_right = {
+                    k.replace("right_", ""): v for k, v in self.calibration.items() if k.startswith("right_")
+                }
+                cal_left = {
+                    k.replace("left_", ""): v for k, v in self.calibration.items() if k.startswith("left_")
+                }
+                self.bus_right.write_calibration(cal_right)
+                self.bus_left.write_calibration(cal_left)
+                return
+
+        logger.info(f"\nRunning calibration for {self}")
+
+        self._calibrate_arm("right", self.bus_right)
+        self._calibrate_arm("left", self.bus_left)
+
+        self._save_calibration()
+        print(f"\nCalibration complete and saved to {self.calibration_fpath}")
+
+    def _calibrate_arm(self, arm_name: str, bus: FeetechMotorsBus) -> None:
+        """Calibrate a single arm with Feetech motors."""
+        logger.info(f"\n=== Calibrating {arm_name.upper()} arm ===")
+
+        bus.disable_torque()
+
+        logger.info(f"Setting Phase to 12 for all motors in {arm_name.upper()} arm...")
+        for motor in bus.motors:
+            bus.write("Phase", motor, 12)
+
+        for motor in bus.motors:
+            bus.write("Operating_Mode", motor, OperatingMode.POSITION.value)
+
+        input(
+            f"\nCalibration: Zero Position ({arm_name.upper()} arm)\n"
+            "Position the arm in the following configuration:\n"
+            "  - Arm hanging straight down\n"
+            "  - Gripper closed\n"
+            "Press ENTER when ready..."
+        )
+
+        homing_offsets = bus.set_half_turn_homings()
+        logger.info(f"{arm_name.capitalize()} arm zero position set.")
+
+        print(f"\nSetting motor ranges for {arm_name.upper()} arm\n")
+
+        if self.calibration is None:
+            self.calibration = {}
+
+        motor_resolution = bus.model_resolution_table[list(bus.motors.values())[0].model]
+        max_res = motor_resolution - 1
+
+        for motor_name, motor in bus.motors.items():
+            prefixed_name = f"{arm_name}_{motor_name}"
+
+            if motor_name == "gripper":
+                input(
+                    f"\nGripper Calibration ({arm_name.upper()} arm)\n"
+                    f"Step 1: CLOSE the gripper fully\n"
+                    f"Press ENTER when gripper is closed..."
+                )
+                closed_pos = bus.read("Present_Position", motor_name, normalize=False)
+                logger.info(f"  Gripper closed position recorded: {closed_pos}")
+
+                input("\nStep 2: OPEN the gripper fully\nPress ENTER when gripper is fully open...")
+                open_pos = bus.read("Present_Position", motor_name, normalize=False)
+                logger.info(f"  Gripper open position recorded: {open_pos}")
+
+                if closed_pos < open_pos:
+                    range_min = int(closed_pos)
+                    range_max = int(open_pos)
+                    drive_mode = 0
+                else:
+                    range_min = int(open_pos)
+                    range_max = int(closed_pos)
+                    drive_mode = 1
+
+                logger.info(
+                    f"  {prefixed_name}: range set to [{range_min}, {range_max}] "
+                    f"(0=closed, 100=open, drive_mode={drive_mode})"
+                )
+            else:
+                range_min = 0
+                range_max = max_res
+                drive_mode = 0
+                logger.info(f"  {prefixed_name}: range set to [0, {max_res}] (full motor range)")
+
+            self.calibration[prefixed_name] = MotorCalibration(
+                id=motor.id,
+                drive_mode=drive_mode,
+                homing_offset=homing_offsets[motor_name],
+                range_min=range_min,
+                range_max=range_max,
+            )
+
+        cal_for_bus = {
+            k.replace(f"{arm_name}_", ""): v
+            for k, v in self.calibration.items()
+            if k.startswith(f"{arm_name}_")
+        }
+        bus.write_calibration(cal_for_bus)
+
+    def configure(self) -> None:
+        self.bus_right.disable_torque()
+        self.bus_right.configure_motors()
+        for motor in self.bus_right.motors:
+            self.bus_right.write("Operating_Mode", motor, OperatingMode.POSITION.value)
+
+        self.bus_left.disable_torque()
+        self.bus_left.configure_motors()
+        for motor in self.bus_left.motors:
+            self.bus_left.write("Operating_Mode", motor, OperatingMode.POSITION.value)
+
+    def setup_motors(self) -> None:
+        print("\nSetting up RIGHT arm motors...")
+        for motor in reversed(self.bus_right.motors):
+            input(f"Connect the controller board to the RIGHT '{motor}' motor only and press enter.")
+            self.bus_right.setup_motor(motor)
+            print(f"RIGHT '{motor}' motor id set to {self.bus_right.motors[motor].id}")
+
+        print("\nSetting up LEFT arm motors...")
+        for motor in reversed(self.bus_left.motors):
+            input(f"Connect the controller board to the LEFT '{motor}' motor only and press enter.")
+            self.bus_left.setup_motor(motor)
+            print(f"LEFT '{motor}' motor id set to {self.bus_left.motors[motor].id}")
+
+    @check_if_not_connected
+    def get_action(self) -> RobotAction:
+        """Get current action from both arms (read positions from all motors)."""
+        start = time.perf_counter()
+
+        right_positions = self.bus_right.sync_read("Present_Position")
+        left_positions = self.bus_left.sync_read("Present_Position")
+
+        action: dict[str, Any] = {}
+        for motor, val in right_positions.items():
+            action[f"right_{motor}.pos"] = -val if motor in RIGHT_MOTORS_TO_FLIP else val
+        for motor, val in left_positions.items():
+            action[f"left_{motor}.pos"] = -val if motor in LEFT_MOTORS_TO_FLIP else val
+
+        dt_ms = (time.perf_counter() - start) * 1e3
+        logger.debug(f"{self} read action: {dt_ms:.1f}ms")
+        return action
+
+    def send_feedback(self, feedback: dict[str, float]) -> None:
+        raise NotImplementedError("Feedback is not yet implemented for OpenArm Mini.")
+
+    @check_if_not_connected
+    def disconnect(self) -> None:
+        self.bus_right.disconnect()
+        self.bus_left.disconnect()
+        logger.info(f"{self} disconnected.")

src/lerobot/teleoperators/utils.py

@@ -95,6 +95,10 @@ def make_teleoperator_from_config(config: TeleoperatorConfig) -> "Teleoperator":
         from .bi_openarm_leader import BiOpenArmLeader
 
         return BiOpenArmLeader(config)
+    elif config.type == "openarm_mini":
+        from .openarm_mini import OpenArmMini
+
+        return OpenArmMini(config)
     else:
         try:
             return cast("Teleoperator", make_device_from_device_class(config))

src/lerobot/utils/control_utils.py

@@ -189,7 +189,7 @@ def sanity_check_dataset_name(repo_id, policy_cfg):
     # Check if dataset_name starts with "eval_" but policy is missing
     if dataset_name.startswith("eval_") and policy_cfg is None:
         raise ValueError(
-            f"Your dataset name begins with 'eval_' ({dataset_name}), but no policy is provided ({policy_cfg.type})."
+            f"Your dataset name begins with 'eval_' ({dataset_name}), but no policy is provided."
         )
 
     # Check if dataset_name does not start with "eval_" but policy is provided