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Hi RGVGreatCoder,
Thanks for reaching out to us.
Referring to VideoCapture(index, apiPreference), the apiPreference for GStreamer is CAP_GSTREAMER.
I have tested it on Raspberry Pi 3. I’ll attach the sample script below.
import cv2 as cv
gst_str = ("filesrc location=bottle-detection.mp4 ! decodebin ! video/x-raw ! queue ! videoconvert ! appsink")
cap = cv.VideoCapture(gst_str, cv.CAP_GSTREAMER)
while cap.isOpened():
ret, frame = cap.read()
if not ret:
print('fail')
break
gray = cv.cvtColor(frame, cv.COLOR_BGR2RGB)
cv.imshow('frame', gray)
if cv.waitKey(1) == ord('q'):
break
cap.release()
cv.destroyAllWindows()
# Extra: Play video in terminal with the following command:
# gst-launch-1.0 v4l2src device=/dev/video0 ! videoconvert ! videoscale ! video/x-raw, width-640, height=360 ! autovideosink
On another note, you may refer to Install GStreamer 1.18 on Raspberry Pi 4 to install the missing dependency.
Next, please refer to the OpenCV-Python tutorial for more OpenCV Python tutorials.
Furthermore, you can refer to the following sample, which uses the gst-launch-1.0 command: Vehicle and Pedestrian Tracking Sample (gst-launch command line).
Best regards,
Wan
Hi RGVGreatCoder,
Glad to know that you’ve successfully displayed the colored vertical bars screen test which indicates that GStreamer is working properly in your system.
For your latest question, it appears to be an issue with your coding.
We’ve successfully run your code with some modifications (called a function actually).
Here is our modified code:
import cv2 as cv
def detectVehicle(file_name,media_source_type):
gst_str = ("filesrc location=" + file_name + " ! decodebin ! video/x-raw ! queue ! videoconvert ! appsink")
if media_source_type == 'V':
cap = cv.VideoCapture(gst_str, cv.CAP_GSTREAMER)
while cap.isOpened():
ret, frame = cap.read()
if not ret:
print('fail')
break
gray = cv.cvtColor(frame, cv.COLOR_BGR2RGB)
cv.imshow('frame', gray)
if cv.waitKey(1) == ord('q'):
break
cap.release()
cv.destroyAllWindows()
def main():
detectVehicle('bottle-detection.mp4','V')
main()
# Extra: Play video in terminal with the following command:
# gst-launch-1.0 v4l2src device=/dev/video0 ! videoconvert ! videoscale ! video/x-raw, width-640, height=360 ! autovideosink
We've also set up our Raspberry Pi 4 with GStreamer for Buster Version 1.14.4 and OpenVINO 2021.4.2 according to your description. We've successfully run the modified code and here are the results:
Best regards,
Wan
Hi RGVGreatCoder,
Regarding the commented code, it was meant only as a reference and unfortunately there was a typo error.
We would appreciate if you could look through any piece of code before executing on your side.
Here is the correct code to launch with USB Webcam device:
gst-launch-1.0 v4l2src device=/dev/video0 ! videoconvert ! videoscale ! video/x-raw, width=640, height=360 ! Autovideosink
And here is the result:
On another note, I would suggest you post your query regarding the GStreamer warning errors in GStreamer Forum. From our side, we've tested and find no issues with GStreamer on our Raspberry Pi Setup.
Lastly, answers for your additional questions are given below :
- OpenVINO version can be found in this text file: /opt/intel/openvino_2021/inference_engine/version.txt
- Not relevant for this particular case.
- Not relevant for this particular case.
- If you've followed the OpenVINO™ toolkit for Raspbian OS installation guide, all required packages are automatically installed for you.
- The above result is replicated using the same hardware and software as yours.
Best Regards,
Wan
