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I'm trying to stream some images form opencv using gstreamer and I got some issues with the pipeline. I'm new to gstreamer and opencv in general. I compiled opencv 3.2 with gstreamer for python3 on a raspberry pi 3. I have a little bash script that I use with raspivid

raspivid -fps 25 -h 720 -w 1080 -vf -n -t 0 -b 2000000 -o - | gst-launch-1.0 -v fdsrc ! h264parse ! rtph264pay config-interval=1 pt=96 ! gdppay ! tcpserversink host=192.168.1.27 port=5000

I wanted to translate this pipeline in order to use it from opencv and feed it images that my algorithm manipulates. I did some research and figured that I can use videoWriter with appsrc instead of fdsrc but I get the following error

GStreamer Plugin: Embedded video playback halted; module appsrc0 reported: Internal data flow error.

The python script that I came up with is the following by the way import cv2

cap = cv2.VideoCapture(0)

# Define the codec and create VideoWriter object
fourcc = cv2.VideoWriter_fourcc(*'MJPG')
out = cv2.VideoWriter('appsrc  ! h264parse ! '
                      'rtph264pay config-interval=1 pt=96 ! '
                      'gdppay ! tcpserversink host=192.168.1.27 port=5000 ',
                      fourcc, 20.0, (640, 480))

while cap.isOpened():
    ret, frame = cap.read()
    if ret:
        frame = cv2.flip(frame, 0)

        # write the flipped frame
        out.write(frame)

        if cv2.waitKey(1) & 0xFF == ord('q'):
            break
    else:
        break

# Release everything if job is finished
cap.release()
out.release()
cv2.destroyAllWindows()

Are there any errors in the pipeline? I don't understand the error. I already have a Python client that can read from the bash pipeline and the results are pretty good from the latency perspective and consumed resources.

1

Please add videoconvert after appsrc as you need to convert format of the video to display it on autovideosink or stream it using udpsink. It could be something like this:

video = cv2.VideoWriter('appsrc ! queue ! videoconvert ! video/x-raw ! omxh264enc ! video/x-h264 ! h264parse ! rtph264pay ! udpsink host=192.168.0.2 port=5000 sync=false',0,25.0,(640,480))
  • Welcome to the Raspberry Pi flavoured corner of the Stack Exchange network - you might like to take the tour to improve your experience on SE. – SlySven Dec 19 '17 at 3:22

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