diff --git a/benchmark/video/run_video_benchmark.py b/benchmark/video/run_video_benchmark.py
index 683b8d95a..d25c2bc02 100644
--- a/benchmark/video/run_video_benchmark.py
+++ b/benchmark/video/run_video_benchmark.py
@@ -63,7 +63,7 @@
 )
 
 
-def parse_int_or_none(value):
+def parse_int_or_none(value) -> int | None:
     if value.lower() == "none":
         return None
     try:
@@ -115,10 +115,10 @@ def save_decoded_frames(
         shutil.copyfile(imgs_dir / f"frame_{idx:06d}.png", save_dir / f"frame_{idx:06d}_original.png")
 
 
-def save_first_episode(imgs_dir: Path, dataset: LeRobotDataset) -> Path:
+def save_first_episode(imgs_dir: Path, dataset: LeRobotDataset) -> None:
     ep_num_images = dataset.episode_data_index["to"][0].item()
     if imgs_dir.exists() and len(list(imgs_dir.glob("frame_*.png"))) == ep_num_images:
-        return imgs_dir
+        return
 
     imgs_dir.mkdir(parents=True, exist_ok=True)
     hf_dataset = dataset.hf_dataset.with_format(None)
@@ -136,10 +136,8 @@ def save_first_episode(imgs_dir: Path, dataset: LeRobotDataset) -> Path:
         if i >= ep_num_images - 1:
             break
 
-    return imgs_dir
-
 
-def sample_timestamps(timestamps_mode: str, ep_num_images: int, fps: int):
+def sample_timestamps(timestamps_mode: str, ep_num_images: int, fps: int) -> list[float]:
     # Start at 5 to allow for 2_frames_4_space and 6_frames
     idx = random.randint(5, ep_num_images - 1)
     match timestamps_mode:
@@ -245,7 +243,7 @@ def benchmark_encoding_decoding(
     save_frames: bool,
     overwrite: bool = False,
     seed: int = 1337,
-):
+) -> list[dict]:
     fps = dataset.fps
 
     if overwrite or not video_path.is_file():