Improves recorder performance and add additional recording capability (#3302)

# Description

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This PR adds fixes from LightWheel Labs and additional functionality to
the IsaacLab recorder.

Fixes # (issue)

- Fixes performance issue when recording long episode data by replacing
the use of torch.cat at every timestep with list append.
- Fixes configclass validation when key is not a string

Adds Functionality

- Adds optional episode meta data to HDF5 recorder
- Adds option to record data pre-physics step
- Adds joint target data to episode data. Joint target data can be
optionally recorded by users and replayed to bypass action term
controllers and improve replay determinism.


## Type of change

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applicable. -->

- Bug fix (non-breaking change which fixes an issue)
- New feature (non-breaking change which adds functionality)

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## Checklist

- [x] I have run the [`pre-commit` checks](https://pre-commit.com/) with
`./isaaclab.sh --format`
- [ ] I have made corresponding changes to the documentation
- [x] My changes generate no new warnings
- [ ] I have added tests that prove my fix is effective or that my
feature works
- [x] I have updated the changelog and the corresponding version in the
extension's `config/extension.toml` file
- [x] I have added my name to the `CONTRIBUTORS.md` or my name already
exists there

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---------
Signed-off-by: Kelly Guo <kellyg@nvidia.com>
Co-authored-by: Kelly Guo <kellyg@nvidia.com>

scripts/imitation_learning/isaaclab_mimic/annotate_demos.py

@@ -358,6 +358,7 @@ def annotate_episode_in_auto_mode(
         annotated_episode = env.recorder_manager.get_episode(0)
         subtask_term_signal_dict = annotated_episode.data["obs"]["datagen_info"]["subtask_term_signals"]
         for signal_name, signal_flags in subtask_term_signal_dict.items():
+            signal_flags = torch.tensor(signal_flags, device=env.device)
             if not torch.any(signal_flags):
                 is_episode_annotated_successfully = False
                 print(f'\tDid not detect completion for the subtask "{signal_name}".')

source/isaaclab/config/extension.toml

 [package]
 
 # Note: Semantic Versioning is used: https://semver.org/
-version = "0.45.10"
+version = "0.45.11"
 
 # Description
 title = "Isaac Lab framework for Robot Learning"

source/isaaclab/docs/CHANGELOG.rst

 Changelog
 ---------
 
-0.45.10 (2025-09-02)
+0.45.11 (2025-09-04)
 ~~~~~~~~~~~~~~~~~~~~
 
 Fixed
 ^^^^^
 
+* Fixes a high memory usage and perf slowdown issue in episode data by removing the use of torch.cat when appending to the episode data
+  at each timestep. The use of torch.cat was causing the episode data to be copied at each timestep, which causes high memory usage and
+  significant performance slowdown when recording longer episode data.
+* Patches the configclass to allow validate dict with key is not a string.
+
+Added
+^^^^^
+
+* Added optional episode metadata (ep_meta) to be stored in the HDF5 data attributes.
+* Added option to record data pre-physics step.
+* Added joint_target data to episode data. Joint target data can be optionally recorded by the user and replayed to improve
+  determinism of replay.
+
+
+0.45.10 (2025-09-02)
+~~~~~~~~~~~~~~~~~~~
+
+Fixed
+^^^^^
+
 * Fixed regression in reach task configuration where the gripper command was being returned.
 * Added :attr:`~isaaclab.devices.Se3GamepadCfg.gripper_term` to :class:`~isaaclab.devices.Se3GamepadCfg`
   to control whether the gamepad device should return a gripper command.

source/isaaclab/isaaclab/envs/manager_based_rl_env.py

@@ -188,6 +188,7 @@ class ManagerBasedRLEnv(ManagerBasedEnv, gym.Env):
             self.scene.write_data_to_sim()
             # simulate
             self.sim.step(render=False)
+            self.recorder_manager.record_post_physics_decimation_step()
             # render between steps only if the GUI or an RTX sensor needs it
             # note: we assume the render interval to be the shortest accepted rendering interval.
             #    If a camera needs rendering at a faster frequency, this will lead to unexpected behavior.

source/isaaclab/isaaclab/managers/recorder_manager.py

@@ -123,6 +123,15 @@ class RecorderTerm(ManagerTermBase):
         """
         return None, None
 
+    def record_post_physics_decimation_step(self) -> tuple[str | None, torch.Tensor | dict | None]:
+        """Record data after the physics step is executed in the decimation loop.
+
+        Returns:
+            A tuple of key and value to be recorded.
+            Please refer to the `record_pre_reset` function for more details.
+        """
+        return None, None
+
 
 class RecorderManager(ManagerBase):
     """Manager for recording data from recorder terms."""
@@ -362,6 +371,16 @@ class RecorderManager(ManagerBase):
             key, value = term.record_post_step()
             self.add_to_episodes(key, value)
 
+    def record_post_physics_decimation_step(self) -> None:
+        """Trigger recorder terms for post-physics step functions in the decimation loop."""
+        # Do nothing if no active recorder terms are provided
+        if len(self.active_terms) == 0:
+            return
+
+        for term in self._terms.values():
+            key, value = term.record_post_physics_decimation_step()
+            self.add_to_episodes(key, value)
+
     def record_pre_reset(self, env_ids: Sequence[int] | None, force_export_or_skip=None) -> None:
         """Trigger recorder terms for pre-reset functions.
 
@@ -406,6 +425,23 @@ class RecorderManager(ManagerBase):
             key, value = term.record_post_reset(env_ids)
             self.add_to_episodes(key, value, env_ids)
 
+    def get_ep_meta(self) -> dict:
+        """Get the episode metadata."""
+        if not hasattr(self._env.cfg, "get_ep_meta"):
+            # Add basic episode metadata
+            ep_meta = dict()
+            ep_meta["sim_args"] = {
+                "dt": self._env.cfg.sim.dt,
+                "decimation": self._env.cfg.decimation,
+                "render_interval": self._env.cfg.sim.render_interval,
+                "num_envs": self._env.cfg.scene.num_envs,
+            }
+            return ep_meta
+
+        # Add custom episode metadata if available
+        ep_meta = self._env.cfg.get_ep_meta()
+        return ep_meta
+
     def export_episodes(self, env_ids: Sequence[int] | None = None) -> None:
         """Concludes and exports the episodes for the given environment ids.
 
@@ -424,8 +460,18 @@ class RecorderManager(ManagerBase):
 
         # Export episode data through dataset exporter
         need_to_flush = False
+
+        if any(env_id in self._episodes and not self._episodes[env_id].is_empty() for env_id in env_ids):
+            ep_meta = self.get_ep_meta()
+            if self._dataset_file_handler is not None:
+                self._dataset_file_handler.add_env_args(ep_meta)
+            if self._failed_episode_dataset_file_handler is not None:
+                self._failed_episode_dataset_file_handler.add_env_args(ep_meta)
+
         for env_id in env_ids:
             if env_id in self._episodes and not self._episodes[env_id].is_empty():
+                self._episodes[env_id].pre_export()
+
                 episode_succeeded = self._episodes[env_id].success
                 target_dataset_file_handler = None
                 if (self.cfg.dataset_export_mode == DatasetExportMode.EXPORT_ALL) or (

source/isaaclab/isaaclab/utils/configclass.py

@@ -268,7 +268,11 @@ def _validate(obj: object, prefix: str = "") -> list[str]:
             missing_fields.extend(_validate(item, prefix=current_path))
         return missing_fields
     elif isinstance(obj, dict):
-        obj_dict = obj
+        # Convert any non-string keys to strings to allow validation of dict with non-string keys
+        if any(not isinstance(key, str) for key in obj.keys()):
+            obj_dict = {str(key): value for key, value in obj.items()}
+        else:
+            obj_dict = obj
     elif hasattr(obj, "__dict__"):
         obj_dict = obj.__dict__
     else:

source/isaaclab/isaaclab/utils/datasets/episode_data.py

@@ -21,6 +21,7 @@ class EpisodeData:
         self._data = dict()
         self._next_action_index = 0
         self._next_state_index = 0
+        self._next_joint_target_index = 0
         self._seed = None
         self._env_id = None
         self._success = None
@@ -110,12 +111,11 @@ class EpisodeData:
         for sub_key_index in range(len(sub_keys)):
             if sub_key_index == len(sub_keys) - 1:
                 # Add value to the final dict layer
+                # Use lists to prevent slow tensor copy during concatenation
                 if sub_keys[sub_key_index] not in current_dataset_pointer:
-                    current_dataset_pointer[sub_keys[sub_key_index]] = value.unsqueeze(0).clone()
+                    current_dataset_pointer[sub_keys[sub_key_index]] = [value.clone()]
                 else:
-                    current_dataset_pointer[sub_keys[sub_key_index]] = torch.cat(
-                        (current_dataset_pointer[sub_keys[sub_key_index]], value.unsqueeze(0))
-                    )
+                    current_dataset_pointer[sub_keys[sub_key_index]].append(value.clone())
                 break
             # key index
             if sub_keys[sub_key_index] not in current_dataset_pointer:
@@ -160,7 +160,7 @@ class EpisodeData:
             elif isinstance(states, torch.Tensor):
                 if state_index >= len(states):
                     return None
-                output_state = states[state_index]
+                output_state = states[state_index, None]
             else:
                 raise ValueError(f"Invalid state type: {type(states)}")
             return output_state
@@ -174,3 +174,47 @@ class EpisodeData:
         if state is not None:
             self._next_state_index += 1
         return state
+
+    def get_joint_target(self, joint_target_index) -> dict | torch.Tensor | None:
+        """Get the joint target of the specified index from the dataset."""
+        if "joint_targets" not in self._data:
+            return None
+
+        joint_targets = self._data["joint_targets"]
+
+        def get_joint_target_helper(joint_targets, joint_target_index) -> dict | torch.Tensor | None:
+            if isinstance(joint_targets, dict):
+                output_joint_targets = dict()
+                for key, value in joint_targets.items():
+                    output_joint_targets[key] = get_joint_target_helper(value, joint_target_index)
+                    if output_joint_targets[key] is None:
+                        return None
+            elif isinstance(joint_targets, torch.Tensor):
+                if joint_target_index >= len(joint_targets):
+                    return None
+                output_joint_targets = joint_targets[joint_target_index]
+            else:
+                raise ValueError(f"Invalid joint target type: {type(joint_targets)}")
+            return output_joint_targets
+
+        output_joint_targets = get_joint_target_helper(joint_targets, joint_target_index)
+        return output_joint_targets
+
+    def get_next_joint_target(self) -> dict | torch.Tensor | None:
+        """Get the next joint target from the dataset."""
+        joint_target = self.get_joint_target(self._next_joint_target_index)
+        if joint_target is not None:
+            self._next_joint_target_index += 1
+        return joint_target
+
+    def pre_export(self):
+        """Prepare data for export by converting lists to tensors."""
+
+        def pre_export_helper(data):
+            for key, value in data.items():
+                if isinstance(value, list):
+                    data[key] = torch.stack(value)
+                elif isinstance(value, dict):
+                    pre_export_helper(value)
+
+        pre_export_helper(self._data)

source/isaaclab/test/managers/test_recorder_manager.py

@@ -78,6 +78,28 @@ class DummyRecorderManagerCfg(RecorderManagerBaseCfg):
     dataset_export_mode = DatasetExportMode.EXPORT_ALL
 
 
+@configclass
+class DummyEnvCfg:
+    """Dummy environment configuration."""
+
+    @configclass
+    class DummySimCfg:
+        """Configuration for the dummy sim."""
+
+        dt = 0.01
+        render_interval = 1
+
+    @configclass
+    class DummySceneCfg:
+        """Configuration for the dummy scene."""
+
+        num_envs = 1
+
+    decimation = 1
+    sim = DummySimCfg()
+    scene = DummySceneCfg()
+
+
 def create_dummy_env(device: str = "cpu") -> ManagerBasedEnv:
     """Create a dummy environment."""
 
@@ -86,8 +108,10 @@ def create_dummy_env(device: str = "cpu") -> ManagerBasedEnv:
 
     dummy_termination_manager = DummyTerminationManager()
     sim = SimulationContext()
+    dummy_cfg = DummyEnvCfg()
+
     return namedtuple("ManagerBasedEnv", ["num_envs", "device", "sim", "cfg", "termination_manager"])(
-        20, device, sim, dict(), dummy_termination_manager
+        20, device, sim, dummy_cfg, dummy_termination_manager
     )
 
 
@@ -142,8 +166,8 @@ def test_record(dataset_dir):
         # check the recorded data
         for env_id in range(env.num_envs):
             episode = recorder_manager.get_episode(env_id)
-            assert episode.data["record_pre_step"].shape == (2, 4)
-            assert episode.data["record_post_step"].shape == (2, 5)
+            assert torch.stack(episode.data["record_pre_step"]).shape == (2, 4)
+            assert torch.stack(episode.data["record_post_step"]).shape == (2, 5)
 
         # Trigger pre-reset callbacks which then export and clean the episode data
         recorder_manager.record_pre_reset(env_ids=None)
@@ -154,4 +178,4 @@ def test_record(dataset_dir):
         recorder_manager.record_post_reset(env_ids=None)
         for env_id in range(env.num_envs):
             episode = recorder_manager.get_episode(env_id)
-            assert episode.data["record_post_reset"].shape == (1, 3)
+            assert torch.stack(episode.data["record_post_reset"]).shape == (1, 3)

source/isaaclab/test/utils/test_episode_data.py

@@ -38,13 +38,13 @@ def test_add_tensors(device):
 
     # test adding data to a key that does not exist
     episode.add("key", dummy_data_0)
-    key_data = episode.data.get("key")
+    key_data = torch.stack(episode.data.get("key"))
     assert key_data is not None
     assert torch.equal(key_data, dummy_data_0.unsqueeze(0))
 
     # test adding data to a key that exists
     episode.add("key", dummy_data_1)
-    key_data = episode.data.get("key")
+    key_data = torch.stack(episode.data.get("key"))
     assert key_data is not None
     assert torch.equal(key_data, expected_added_data)
 
@@ -52,7 +52,7 @@ def test_add_tensors(device):
     episode.add("first/second", dummy_data_0)
     first_data = episode.data.get("first")
     assert first_data is not None
-    second_data = first_data.get("second")
+    second_data = torch.stack(first_data.get("second"))
     assert second_data is not None
     assert torch.equal(second_data, dummy_data_0.unsqueeze(0))
 
@@ -60,7 +60,7 @@ def test_add_tensors(device):
     episode.add("first/second", dummy_data_1)
     first_data = episode.data.get("first")
     assert first_data is not None
-    second_data = first_data.get("second")
+    second_data = torch.stack(first_data.get("second"))
     assert second_data is not None
     assert torch.equal(second_data, expected_added_data)
 
@@ -83,15 +83,15 @@ def test_add_dict_tensors(device):
     episode.add("key", dummy_dict_data_0)
     key_data = episode.data.get("key")
     assert key_data is not None
-    key_0_data = key_data.get("key_0")
+    key_0_data = torch.stack(key_data.get("key_0"))
     assert key_0_data is not None
     assert torch.equal(key_0_data, torch.tensor([[0]], device=device))
     key_1_data = key_data.get("key_1")
     assert key_1_data is not None
-    key_1_0_data = key_1_data.get("key_1_0")
+    key_1_0_data = torch.stack(key_1_data.get("key_1_0"))
     assert key_1_0_data is not None
     assert torch.equal(key_1_0_data, torch.tensor([[1]], device=device))
-    key_1_1_data = key_1_data.get("key_1_1")
+    key_1_1_data = torch.stack(key_1_data.get("key_1_1"))
     assert key_1_1_data is not None
     assert torch.equal(key_1_1_data, torch.tensor([[2]], device=device))
 
@@ -99,15 +99,15 @@ def test_add_dict_tensors(device):
     episode.add("key", dummy_dict_data_1)
     key_data = episode.data.get("key")
     assert key_data is not None
-    key_0_data = key_data.get("key_0")
+    key_0_data = torch.stack(key_data.get("key_0"))
     assert key_0_data is not None
     assert torch.equal(key_0_data, torch.tensor([[0], [3]], device=device))
     key_1_data = key_data.get("key_1")
     assert key_1_data is not None
-    key_1_0_data = key_1_data.get("key_1_0")
+    key_1_0_data = torch.stack(key_1_data.get("key_1_0"))
     assert key_1_0_data is not None
     assert torch.equal(key_1_0_data, torch.tensor([[1], [4]], device=device))
-    key_1_1_data = key_1_data.get("key_1_1")
+    key_1_1_data = torch.stack(key_1_data.get("key_1_1"))
     assert key_1_1_data is not None
     assert torch.equal(key_1_1_data, torch.tensor([[2], [5]], device=device))
 
@@ -119,7 +119,7 @@ def test_get_initial_state(device):
     episode = EpisodeData()
 
     episode.add("initial_state", dummy_initial_state)
-    initial_state = episode.get_initial_state()
+    initial_state = torch.stack(episode.get_initial_state())
     assert initial_state is not None
     assert torch.equal(initial_state, dummy_initial_state.unsqueeze(0))
 

source/isaaclab/test/utils/test_hdf5_dataset_file_handler.py

@@ -82,6 +82,7 @@ def test_write_and_load_episode(temp_dir, device):
     test_episode = create_test_episode(device)
 
     # write the episode to the dataset
+    test_episode.pre_export()
     dataset_file_handler.write_episode(test_episode)
     dataset_file_handler.flush()