Recordscreen and encode H264 video

Our program need recordscreen, encode to H264 stream and push to a external server.

Is there any way we can capture screen to like RGB or YUV image quickly, then we can encode them to H264 video?

You may try to do that with gstreamer (this would record X screen @30fps, rescale with HW into 720p, encode with HW into H264, put into a mp4/mov container and save into file. Stop with Ctrl-C):

gst-launch-1.0 ximagesrc use_damage=0 ! queue ! nvvidconv ! 'video/x-raw(memory:NVMM),format=NV12,width=1280,height=720,framerate=30/1' ! nvv4l2h264enc ! h264parse ! qtmux ! filesink location=test_h264.mp4 -e

Thanks, @Honey_Patouceul

After we capture the screen and get an image, we will need draw something on the image, then encode it to a video. So we may not use the above gstreamer command. Dont know if we can have some API to capture screen.

You may try using XLib. Have a look to how ximagesrc uses it;

Also note that you can use a gstreamer pipeline for capturing from screen, process frame, then use another gstreamer pipeline for encoding and saving/streaming. It would be very easy with OpenCV.

Great. We do need push the encoded H264 video to remote by udp and also need save the H264 video to local with mp4 file.

You would try:

#!/usr/bin/env python

import cv2

# This pipeline captures screen @ 30 fps, resize to 1280x720, and convert into BGR 
cap = cv2.VideoCapture("ximagesrc use_damage=0 ! nvvidconv ! video/x-raw(memory:NVMM), format=(string)NV12, width=1280,height=720,framerate=(fraction)30/1 ! nvvidconv ! video/x-raw, format=(string)BGRx ! videoconvert ! video/x-raw, format=(string)BGR ! queue ! appsink drop=1", cv2.CAP_GSTREAMER)
if not cap.isOpened():
   print('Failed to open camera')

# This pipeline converts to NV12 format into NVMM memory, encodes into h264, 
# then forks into one branch streaming as RTP-MP2T to localhost port 5004, 
# and one branch putting into MP4/MOV container and save to file.
out = cv2.VideoWriter("appsrc ! queue ! videoconvert ! video/x-raw,format=BGRx ! nvvidconv ! nvv4l2h264enc insert-sps-pps=1 insert-vui=1 idrinterval=15 ! tee name=t ! queue ! h264parse ! mpegtsmux ! rtpmp2tpay ! udpsink host= port=5004      t. ! queue ! h264parse ! qtmux ! filesink location=test.mp4 ", cv2.CAP_GSTREAMER, 0, 30.0, (1280,720)) 
if not out.isOpened():
   print('Failed to open output writer')

# Loop for 100 seconds
for i in range(3000):
	# Read image from capture
	ret_val, img =;
	if not ret_val:

	# Your drawing a green rectangle
	cv2.rectangle(img, (100,100), (400,400), (0,255,0), thickness=2, lineType=2)

	# Push processed image into writer

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