diff --git a/src/sharp/utils/io.py b/src/sharp/utils/io.py
index 07a98be..bee5d97 100644
--- a/src/sharp/utils/io.py
+++ b/src/sharp/utils/io.py
@@ -189,6 +189,7 @@ def __init__(self, output_path: Path, fps: float = 30.0, render_depth: bool = Tr
         self.image_writer = iio.get_writer(output_path, fps=fps)
 
         self.max_depth_estimate = None
+        self.depth_writer = None
         if render_depth:
             self.depth_writer = iio.get_writer(output_path.with_suffix(".depth.mp4"), fps=fps)
 
@@ -211,3 +212,5 @@ def add_frame(self, image: torch.Tensor, depth: torch.Tensor) -> None:
     def close(self):
         """Finish writing."""
         self.image_writer.close()
+        if self.depth_writer is not None:
+            self.depth_writer.close()