Multithreading with open cv and FFMPEG

Hi, I'm working on a project which get several CCTV streams and preform some processing with OpenCV. Then I want to get those streams back with rtmp/rtsp protocols.

I can use openCV with threading in python and preform my processing and return in scale of 4 frames from each stream sequentially. Is there any way to use this python library and FFMPEG to send each stream to corresponding rtmp/rtsp with FFMPG?

 class LoadStreams:  # multiple IP or RTSP cameras
  def __init__(self, sources='streams.txt', img_size =(1290,720)):
      self.mode = 'images'
      self.img_size = img_size


      if os.path.isfile(sources):
          with open(sources, 'r') as f:
              sources = [x.strip() for x in f.read().splitlines() if len(x.strip())]
      else:
          sources = [sources]

      n = len(sources)
      self.imgs = [None] * n
      self.sources = sources
      for i, s in enumerate(sources):
          cap = cv2.VideoCapture(eval(s) if s.isnumeric() else s)
          assert cap.isOpened(), 'Failed to open %s' % s
          w = int(cap.get(cv2.CAP_PROP_FRAME_WIDTH))
          h = int(cap.get(cv2.CAP_PROP_FRAME_HEIGHT))
          self.fps = cap.get(cv2.CAP_PROP_FPS) % 100
          _, self.imgs[i] = cap.read()  # guarantee first frame
          thread = Thread(target=self.update, args=([i, cap]), daemon=True)
          print(' success (%gx%g at %.2f FPS).' % (w, h, self.fps))
          thread.start()


  def update(self, index, cap):
      n = 0
      while cap.isOpened():
          n += 1
          # _, self.imgs[index] = cap.read()
          cap.grab()
          if n == 4:  # read every 4th frame
              _, self.imgs[index] = cap.retrieve()
              n = 0
          time.sleep(0.01)  # wait time

  def __iter__(self):
      self.count = -1
      return self

  def __next__(self):
      self.count += 1
      img0 = self.imgs.copy()
      if cv2.waitKey(1) == ord('q'):  # q to quit
          cv2.destroyAllWindows()
          raise StopIteration