From 08fbbb318f4825769f6891ff907525a3d5aa3431 Mon Sep 17 00:00:00 2001
From: Simon Alibert <simon.alibert@huggingface.co>
Date: Thu, 8 May 2025 13:15:59 +0200
Subject: [PATCH] Add replay

---
 lerobot/replay.py | 86 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 86 insertions(+)
 create mode 100644 lerobot/replay.py

diff --git a/lerobot/replay.py b/lerobot/replay.py
new file mode 100644
index 000000000..0de0d4539
--- /dev/null
+++ b/lerobot/replay.py
@@ -0,0 +1,86 @@
+# Copyright 2024 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 dataclasses import asdict, dataclass
+from pathlib import Path
+from pprint import pformat
+
+import draccus
+
+from lerobot.common.datasets.lerobot_dataset import LeRobotDataset
+from lerobot.common.robots import (  # noqa: F401
+    Robot,
+    RobotConfig,
+    koch_follower,
+    make_robot_from_config,
+    so100_follower,
+)
+from lerobot.common.utils.robot_utils import busy_wait
+from lerobot.common.utils.utils import (
+    init_logging,
+    log_say,
+)
+
+
+@dataclass
+class DatasetReplayConfig:
+    # Dataset identifier. By convention it should match '{hf_username}/{dataset_name}' (e.g. `lerobot/test`).
+    repo_id: str
+    # Episode to replay.
+    episode: int
+    # Root directory where the dataset will be stored (e.g. 'dataset/path').
+    root: str | Path | None = None
+    # Limit the frames per second. By default, uses the policy fps.
+    fps: int = 30
+
+
+@dataclass
+class ReplayConfig:
+    robot: RobotConfig
+    dataset: DatasetReplayConfig
+    # Use vocal synthesis to read events.
+    play_sounds: bool = True
+
+
+@draccus.wrap()
+def replay(cfg: ReplayConfig):
+    init_logging()
+    logging.info(pformat(asdict(cfg)))
+
+    robot = make_robot_from_config(cfg.robot)
+    dataset = LeRobotDataset(cfg.dataset.repo_id, root=cfg.dataset.root, episodes=[cfg.dataset.episode])
+    actions = dataset.hf_dataset.select_columns("action.joints")
+    robot.connect()
+
+    log_say("Replaying episode", cfg.play_sounds, blocking=True)
+    for idx in range(dataset.num_frames):
+        start_episode_t = time.perf_counter()
+
+        action_array = actions[idx]["action.joints"]
+        action = {}
+        for i, name in enumerate(dataset.features["action.joints"]["names"]):
+            action[name] = action_array[i]
+
+        robot.send_action(action)
+
+        dt_s = time.perf_counter() - start_episode_t
+        busy_wait(1 / dataset.fps - dt_s)
+
+    robot.disconnect()
+
+
+if __name__ == "__main__":
+    replay()