how to stream frames using gstreamer 2c with opencv in python 3f

1"""How to stream frames using gstreamer, with opencv in python?
2https://forums.developer.nvidia.com/t/how-to-stream-frames-using-gstreamer-with-opencv-in-python/121036/2
3"""
4
5import cv2
6
7cap = cv2.VideoCapture("rtsp://admin:xxxx@10.168.1.248:554/h264/ch1/main/av_stream")
8
9out = cv2.VideoWriter("appsrc ! video/x-raw, format=BGR ! queue ! videoconvert ! video/x-raw, format=BGRx ! nvvidconv ! omxh264enc ! video/x-h264, stream-format=byte-stream ! h264parse ! rtph264pay pt=96 config-interval=1 ! udpsink host=10.168.1.177 port=50001", cv2.CAP_GSTREAMER, 0, 25.0, (1920,1080))
10
11while cap.isOpened():
12    ret, frame = cap.read()
13    if ret:
14        if out.isOpened():
15            out.write(frame)
16            print('writing frame')
17        if cv2.waitKey(1) & 0xFF == ord('q'):
18            break
19    else:
20        break
21
22# Release everything if job is finished
23cap.release()
24out.release()
25