Fix MP4 recording with FFmpeg-enabled OpenCV

Author: dengyuchenkit

requirements.txt

@@ -8,6 +8,7 @@ msgpack==1.1.2
 numpy>=2.0,<2.8
 onnx==1.20.1
 onnxruntime-gpu==1.25.1
+opencv-python-headless==4.14.0.94
 pandas==3.0.1
 pytorch-lightning==2.6.1
 timm==1.0.26

run.py

@@ -189,6 +189,15 @@
     parser.error("--nurec-omap-file requires --nurec-scene.")
 apply_nurec_spg_kit_args(args_cli)
 
+if args_cli.video:
+    # Load the FFmpeg-enabled wheel before Kit prepends its bundled OpenCV to sys.path.
+    import cv2
+
+    if not cv2.videoio_registry.hasBackend(cv2.CAP_FFMPEG):
+        parser.error(
+            "--video requires FFmpeg-enabled OpenCV. Install requirements.txt and recreate "
+            f"the Docker container after rebuilding the image. Loaded OpenCV: {cv2.__file__}")
+
 # launch omniverse app
 app_launcher = AppLauncher(args_cli, enable_cameras=True)
 simulation_app = app_launcher.app