Networking tutorials

OpenCV and Real time streaming protocol (RTSP)

 · 2 mins read

Hello friends, this tutorial is about RTSP stream basics, how to process it, and obtain frames in Python. In general, OpenCV is used with webcams connected to computers or also embedded inside them. However, for the surveillance purpose, we commonly use IP cameras that generate video streams using RTSP protocol. We can use such IP cameras in projects of video processing, like motion detection, etc. So let’s start by knowing what RTSP is.

RTSP

It is a network control protocol to deliver multimedia content across the desired networks. With TCP, it provides a reliable stream, and its structure is similar to the HTTP. It was designed mainly for entertainment and communications systems to access and control streaming media servers. The clients can issue commands to the media server like play, record, pause, etc. to enable real-time control of the media servers. RTSP allows for video-on-demand solutions.

Lets try to open some rtsp and http links:

  1. “rtsp://freja.hiof.no:1935/rtplive/definst/hessdalen03.stream”
  2. “http://wmccpinetop.axiscam.net/mjpg/video.mjpg”

Here is the code to obtain frames of video from the rtsp link.


import cv2
# vid = cv2.VideoCapture(0) # For webcam
vid = cv2.VideoCapture("http://wmccpinetop.axiscam.net/mjpg/video.mjpg") # For streaming links
while True:
  _,frame = vid.read()
  print(frame)
  cv2.imshow('Video Live IP cam',frame)
  key = cv2.waitKey(1) & 0xFF
  if key ==ord('q'):
    break

vid.release()
cv2.destroyAllWindows()

The general syntax of rtsp stream for IP cameras are like:

rtsp://UserName:Password@IpAdress:Port/Streaming/Channels/ChannelID

According to your settings, give the parameters in the link and use in your opencv projects.

Experiment of live webcam stream on webcam

Issue this command in Terminal:

ffmpeg -f avfoundation -pix_fmt yuyv422 -video_size 640x480 -framerate 30 -i "0:0" -ac 2 -vf format=yuyv422 -vcodec libx264 -maxrate 2000k -bufsize 2000k -acodec aac -ar 44100 -b:a 128k -f rtp_mpegts rtp://127.0.0.1:9999

In another terminal run this python code

import cv2
# vid = cv2.VideoCapture(0) # For webcam
vid = cv2.VideoCapture("rtp://127.0.0.1:9999") # For streaming links
while True:
	rdy,frame = vid.read()
	print(rdy)
	try:
	  cv2.imshow('Video Live IP cam',frame)
	  key = cv2.waitKey(1) & 0xFF
	  if key ==ord('q'):
	    break
	except:
		pass

vid.release()
cv2.destroyAllWindows()

Wait for the frames to get appear (may take up 10 seconds) after some messages!