Update app.py

app.py

@@ -360,6 +360,9 @@ def main():
     # File upload
     col1, col2 = st.columns(2)
     
+    # Initialize video_path variable
+    video_path = None
+    
     with col1:
         st.markdown("### 📹 Upload Video")
         uploaded_video = st.file_uploader(
@@ -437,7 +440,7 @@ def main():
                 st.info("Please upload a background image")
     
     # Process button
-    if uploaded_video and st.button("🎬 Process Video", type="primary"):
+    if uploaded_video and video_path and st.button("🎬 Process Video", type="primary"):
         
         # Check if background is selected
         if background_method == "📋 Preset Backgrounds" and not background_url: