Label RSL-RL play videos with checkpoint stems

source/isaaclab_rl/changelog.d/rsl-rl-play-video-checkpoint-prefix.rst

@@ -0,0 +1,4 @@
+Fixed
+^^^^^
+
+* Fixed RSL-RL play video filenames missing the numeric checkpoint stem used for playback.

source/isaaclab_rl/isaaclab_rl/entrypoints/backends/play_rsl_rl.py

@@ -164,7 +164,7 @@ def main(env_cfg: ManagerBasedRLEnvCfg | DirectRLEnvCfg | DirectMARLEnvCfg, agen
             log_dir = os.path.dirname(resume_path)
 
             env_cfg.log_dir = log_dir
-            apply_video_recording(env_cfg, log_dir, args_cli, subdir="play")
+            apply_video_recording(env_cfg, log_dir, args_cli, subdir="play", checkpoint_path=resume_path)
 
             screen.stage("Creating environment")
             env = create_isaaclab_env(

source/isaaclab_rl/isaaclab_rl/entrypoints/common.py

@@ -783,7 +783,14 @@ def pre_launch_video_config(env_cfg: Any, log_dir: str | None = None, args_cli:
         pass
 
 
-def apply_video_recording(env_cfg: Any, log_dir: str, args_cli: argparse.Namespace, *, subdir: str = "train") -> None:
+def apply_video_recording(
+    env_cfg: Any,
+    log_dir: str,
+    args_cli: argparse.Namespace,
+    *,
+    subdir: str = "train",
+    checkpoint_path: str | None = None,
+) -> None:
     """Configure internal video recording on the environment config.
 
     Enables recording by ensuring ``env_cfg.video_recorders`` is non-empty, then applies
@@ -809,6 +816,8 @@ def apply_video_recording(env_cfg: Any, log_dir: str, args_cli: argparse.Namespa
         args_cli: Parsed command-line arguments.
         subdir: Sub-directory name appended to ``<log_dir>/videos/`` for the fallback output
             path.  Use ``"train"`` for training runs and ``"play"`` for evaluation.
+        checkpoint_path: Checkpoint loaded by a play run.  When set to a ``model_<N>.pt``
+            path with a numeric id, the checkpoint stem is appended to play video names.
     """
     if not getattr(args_cli, "video", False):
         return
@@ -950,6 +959,8 @@ def apply_video_recording(env_cfg: Any, log_dir: str, args_cli: argparse.Namespa
             cfg.video_length = video_length
         if video_interval is not None:
             cfg.video_interval = video_interval
+        if subdir == "play" and (label := _checkpoint_video_label(checkpoint_path)) is not None:
+            cfg.output_filename_prefix = _checkpoint_video_prefix(cfg.output_filename_prefix, label)
 
     print("[INFO] Video recording enabled.")
     for cfg in env_cfg.video_recorders:
@@ -964,6 +975,22 @@ def apply_video_recording(env_cfg: Any, log_dir: str, args_cli: argparse.Namespa
         )
 
 
+def _checkpoint_video_label(checkpoint_path: str | None) -> str | None:
+    if checkpoint_path is None:
+        return None
+
+    path = Path(checkpoint_path)
+    if re.fullmatch(r"model_\d+", path.stem) is None or path.suffix != ".pt":
+        return None
+    return path.stem
+
+
+def _checkpoint_video_prefix(prefix: str, label: str) -> str:
+    if prefix == label or prefix.endswith(f"_{label}"):
+        return prefix
+    return f"{prefix}_{label}"
+
+
 def wrap_record_video(env, log_dir: str, args_cli: argparse.Namespace):
     """No-op stub kept for backwards compatibility.
 

source/isaaclab_rl/test/test_apply_video_recording.py

@@ -74,6 +74,42 @@ def test_apply_video_recording_injects_correct_recorder():
     assert rec.video_length == 42  # CLI override applied
     assert rec.video_interval == 500  # CLI override applied
     assert rec.output_dir == os.path.join("/my/log", "videos", "play")
+    assert rec.output_filename_prefix == "clip"
+
+
+@pytest.mark.parametrize(
+    ("existing_prefix", "checkpoint_name", "expected_prefix"),
+    [
+        ("clip", "model_1200.pt", "clip_model_1200"),
+        ("eval", "model_42.pt", "eval_model_42"),
+        # Overlapping numeric ids stay distinct tokens instead of substrings.
+        ("clip_model_1200", "model_120.pt", "clip_model_1200_model_120"),
+        # Non-model or non-numeric stems keep the configured prefix.
+        ("clip", "custom_1200.pt", "clip"),
+        ("clip", "final.pt", "clip"),
+    ],
+)
+def test_apply_video_recording_labels_play_video_with_checkpoint_stem(existing_prefix, checkpoint_name, expected_prefix):
+    """Play videos append only a numeric model checkpoint stem, kept as a distinct token."""
+    from isaaclab.envs.utils.video_recorder_cfg import VideoRecorderCfg
+
+    existing = VideoRecorderCfg()
+    existing.output_filename_prefix = existing_prefix
+
+    env_cfg = _env_cfg()
+    env_cfg.video_recorders = [existing]
+    apply_video_recording(env_cfg, "/my/log", _args(), subdir="play", checkpoint_path=f"/my/log/{checkpoint_name}")
+
+    assert env_cfg.video_recorders[0].output_filename_prefix == expected_prefix
+
+
+def test_apply_video_recording_leaves_train_video_prefix_unchanged():
+    """Checkpoint labels are only applied to play videos, not training videos."""
+
+    env_cfg = _env_cfg()
+    apply_video_recording(env_cfg, "/my/log", _args(), checkpoint_path="/my/log/model_1200.pt")
+
+    assert env_cfg.video_recorders[0].output_filename_prefix == "clip"
 
 
 def test_apply_video_recording_uses_cfg_defaults_when_cli_not_passed():