diff --git a/src/jax_loop_utils/metric_writers/mlflow/metric_writer.py b/src/jax_loop_utils/metric_writers/mlflow/metric_writer.py
index 81d889f..95c4a35 100644
--- a/src/jax_loop_utils/metric_writers/mlflow/metric_writer.py
+++ b/src/jax_loop_utils/metric_writers/mlflow/metric_writer.py
@@ -2,6 +2,7 @@
 
 import os
 import pathlib
+import shutil
 import tempfile
 import time
 from collections.abc import Mapping
@@ -123,27 +124,36 @@ def write_videos(self, step: int, videos: Mapping[str, Array]):
 
         encode_and_log = maybe_async(self._encode_and_log_video)
 
-        temp_dir = pathlib.Path(tempfile.mkdtemp())
         paths_arrays = [
             (
-                temp_dir / f"{key}_{step:09d}.{_audio_video.CONTAINER_FORMAT}",
+                f"{key}_{step:09d}.{_audio_video.CONTAINER_FORMAT}",
                 video_array,
             )
             for key, video_array in videos.items()
         ]
 
+        temp_dir = pathlib.Path(tempfile.mkdtemp())
         for path, video_array in paths_arrays:
-            encode_and_log(path, video_array)
+            encode_and_log(temp_dir, path, video_array)
 
         pool.close()
+        shutil.rmtree(temp_dir)
 
-    def _encode_and_log_video(self, path: pathlib.Path, video_array: Array):
-        with open(path, "wb") as f:
+    def _encode_and_log_video(
+        self, temp_dir: pathlib.Path, rel_path: str, video_array: Array
+    ):
+        temp_path = temp_dir / rel_path
+        # handle keys with slashes
+        if not temp_path.parent.exists():
+            temp_path.parent.mkdir(parents=True, exist_ok=True)
+        with open(temp_path, "wb") as f:
             _audio_video.encode_video(video_array, f)  # pyright: ignore[reportOptionalMemberAccess]
         # If log_artifact(synchronous=False) existed,
         # we could synchronize with self.flush() rather than at the end of write_videos.
         # https://github.com/mlflow/mlflow/issues/14153
-        self._client.log_artifact(self._run_id, path, os.path.join("videos", path.name))
+        self._client.log_artifact(
+            self._run_id, temp_path, os.path.join("videos", rel_path)
+        )
 
     def write_audios(self, step: int, audios: Mapping[str, Array], *, sample_rate: int):
         """MLflow doesn't support audio logging directly."""
diff --git a/src/jax_loop_utils/metric_writers/mlflow/metric_writer_test.py b/src/jax_loop_utils/metric_writers/mlflow/metric_writer_test.py
index c7f265e..3771fcf 100644
--- a/src/jax_loop_utils/metric_writers/mlflow/metric_writer_test.py
+++ b/src/jax_loop_utils/metric_writers/mlflow/metric_writer_test.py
@@ -83,8 +83,6 @@ def test_write_images(self):
             run = runs[0]
             # the string "images" is hardcoded in MlflowClient.log_image.
             artifacts = writer._client.list_artifacts(run.info.run_id, "images")
-            if not artifacts:
-                artifacts = writer._client.list_artifacts(run.info.run_id, "images")
             artifact_paths = [artifact.path for artifact in artifacts]
             self.assertGreaterEqual(len(artifact_paths), 1)
             self.assertIn("test_image", artifact_paths[0])
@@ -141,7 +139,7 @@ def test_write_videos(self):
                 frames.append(frame)
 
             videos = {
-                "noise_0": np.stack(frames, axis=0),
+                "zzz/noise_0": np.stack(frames, axis=0),
                 "noise_1": np.stack(frames, axis=0),
             }
             writer.write_videos(0, videos)
@@ -152,19 +150,17 @@ def test_write_videos(self):
             self.assertEqual(len(runs), 1)
             run = runs[0]
 
-            artifacts = writer._client.list_artifacts(run.info.run_id, "videos")
-            if not artifacts:
-                artifacts = writer._client.list_artifacts(run.info.run_id, "videos")
-
-            artifact_paths = [artifact.path for artifact in artifacts]
-            self.assertEqual(len(artifact_paths), 2)
-            self.assertTrue(
-                any(path.startswith("videos/noise_0") for path in artifact_paths)
-            )
-            self.assertTrue(
-                any(path.startswith("videos/noise_1") for path in artifact_paths)
+            artifacts_videos = writer._client.list_artifacts(run.info.run_id, "videos")
+            self.assertEqual(len(artifacts_videos), 2)
+            sorted_artifacts_videos = sorted(artifacts_videos, key=lambda x: x.path)
+            self.assertEqual(
+                sorted_artifacts_videos[0].path, "videos/noise_1_000000000.mp4"
             )
 
+            artifacts_zzz = writer._client.list_artifacts(run.info.run_id, "videos/zzz")
+            self.assertEqual(len(artifacts_zzz), 1)
+            self.assertEqual(artifacts_zzz[0].path, "videos/zzz/noise_0_000000000.mp4")
+
     def test_no_ops(self):
         with tempfile.TemporaryDirectory() as temp_dir:
             tracking_uri = f"file://{temp_dir}"