Update app.py

app.py

@@ -8,9 +8,10 @@ st.markdown("Upload a video or select the example")
 
 ## Select video to inference
 f = st.file_uploader(" Upload a video ", type=["mp4"])
-tfile = tempfile.NamedTemporaryFile(delete=False)
-tfile.write(f.read())
-file_video = tfile.name
+if f is not None:
+    tfile = tempfile.NamedTemporaryFile(delete=False)
+    tfile.write(f.read())
+    file_video = tfile.name
 
 if st.button("example"):
     file_video = "test_video.mp4"