Read Frames from RTSP Stream in Python

Question

I have recently set up a Raspberry Pi camera and am streaming the frames over RTSP. While it may not be completely necessary, here is the command I am using the broadcast the video:

raspivid -o - -t 0 -w 1280 -h 800 |cvlc -vvv stream:///dev/stdin --sout '#rtp{sdp=rtsp://:8554/output.h264}' :demux=h264

This streams the video perfectly.

What I would now like to do is parse this stream with Python and read each frame individually. I would like to do some motion detection for surveillance purposes.

I am completely lost on where to start on this task. Can anyone point me to a good tutorial? If this is not achievable via Python, what tools/languages can I use to accomplish this?

Answer 1

Using the same method listed by "depu" worked perfectly for me. I just replaced "video file" with "RTSP URL" of actual camera. Example below worked on AXIS IP Camera. (This was not working for a while in previous versions of OpenCV) Works on OpenCV 3.4.1 Windows 10)

import cv2
cap = cv2.VideoCapture("rtsp://root:[email protected]:554/axis-media/media.amp")

while(cap.isOpened()):
    ret, frame = cap.read()
    cv2.imshow('frame', frame)
    if cv2.waitKey(20) & 0xFF == ord('q'):
        break
cap.release()
cv2.destroyAllWindows()

Answer 2

Bit of a hacky solution, but you can use the VLC python bindings (you can install it with pip install python-vlc) and play the stream:

import vlc
player=vlc.MediaPlayer('rtsp://:8554/output.h264')
player.play()

Then take a snapshot every second or so:

while 1:
    time.sleep(1)
    player.video_take_snapshot(0, '.snapshot.tmp.png', 0, 0)

And then you can use SimpleCV or something for processing (just load the image file '.snapshot.tmp.png' into your processing library).