diff --git a/python/xrprimer/utils/ffmpeg_utils.py b/python/xrprimer/utils/ffmpeg_utils.py
index 4a6343f..106f236 100644
--- a/python/xrprimer/utils/ffmpeg_utils.py
+++ b/python/xrprimer/utils/ffmpeg_utils.py
@@ -8,7 +8,6 @@
 from pathlib import Path
 from typing import Any, Tuple, Union
 
-import cv2
 import numpy as np
 
 from .log_utils import get_logger
@@ -484,6 +483,8 @@ def images_to_array_opencv(
     Returns:
         np.ndarray: shape will be (f * h * w * 3).
     """
+    import cv2
+
     check_path(
         input_path=input_folder,
         allowed_existence=[Existence.DirectoryExistNotEmpty],
diff --git a/requirements/runtime.txt b/requirements/runtime.txt
index 6bad103..24ce15a 100644
--- a/requirements/runtime.txt
+++ b/requirements/runtime.txt
@@ -1,2 +1 @@
 numpy
-scipy
diff --git a/requirements/synbody.txt b/requirements/synbody.txt
index 418a4da..5bb8559 100644
--- a/requirements/synbody.txt
+++ b/requirements/synbody.txt
@@ -1,3 +1,4 @@
 imath
 numpy
 openexr
+scipy