I want to upload a video and show the new processed video

🎈 Using Streamlit
1

This is my code:

    if path_type=="mp4":
        
        temp_file_result  = './temp_file_2.mp4'

        tfile = tempfile.NamedTemporaryFile(delete=False)
        tfile.write(uploaded_file.read())
        cap = cv2.VideoCapture(tfile.name)
        

        
        frame_width = int(cap.get(3))
        frame_height = int(cap.get(4))
        
        fourcc = cv2.VideoWriter_fourcc(*'MP4V')
        new_my_video = './temp_file_2.mp4'
        out = cv2.VideoWriter(new_my_video, fourcc, 18, (frame_width, frame_height))
        
        while(cap.isOpened()):
            
            ret, frame = cap.read()
            
            if ret==True:
                
                age_img = classify_age(frame)
                age_img = cv2.cvtColor(age_img, cv2.COLOR_BGR2RGB)
               
                out.write(age_img)
        
            else:
                break
        st.video(new_my_video)

        cap.release()
        out.release()

However, I only get an empty video player.