Could not find the Qt platform plugin "wayland" in opencv path

[likehengqq]

Expected behaviour

Write here how did you expect the library to function.

Actual behaviour

Write here what went wrong.

Warning: Ignoring XDG_SESSION_TYPE=wayland on Gnome. Use QT_QPA_PLATFORM=wayland to run on Wayland anyway.
qt.qpa.plugin: Could not find the Qt platform plugin "wayland" in "/home/firefly/venv/lib/python3.9/site-packages/cv2/qt/plugins"
This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.

Available platform plugins are: xcb.

Aborted (core dumped)

Steps to reproduce

• example code

import cv2
cap=cv2.VideoCapture(8)
while True:
    ret,frame =cap.read()
    frame=cv2.flip(frame,1)
    cv2.imshow('frame',frame)
    if cv2.waitKey(1)&0xff==ord('q'):
        break
cap.release()
cv2.destroyAllWindows()

• operating system: ubuntu 20.04
• architecture (e.g. x86): aarch64
• opencv-python version: opencv_python-4.5.1.48-cp39-cp39

Issue submission checklist

• This is not a generic OpenCV usage question (looking for help for coding, other usage questions, homework etc.)
• I have read the README of this repository and understand that this repository provides only an automated build toolchain for OpenCV Python packages (there is no actual OpenCV code here)
• The issue is related to the build scripts in this repository, to the pre-built binaries or is a feature request (such as "please enable this additional dependency")
• I'm using the latest version of opencv-python

[KaranParekh11]

i also have same problem with latest version of opencv-python.If any one was able to solve this issue please reply here.

[hitbuyi]

I have the same problem for opencv-python 4.5.x,4.6.x, the error message is

Connected to pydev debugger (build 201.8538.36)
QObject::moveToThread: Current thread (0x55ae47946190) is not the object's thread (0x55ae4795d6b0).
Cannot move to target thread (0x55ae47946190)

qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "/home/hitbuyi/.conda/envs/py1121/lib/python3.9/site-packages/cv2/qt/plugins" even though it was found.
This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.

Available platform plugins are: xcb, eglfs, linuxfb, minimal, minimalegl, offscreen, vnc, wayland-egl, wayland, wayland-xcomposite-egl, wayland-xcomposite-glx, webgl.

My environments are
OS: ubuntu20.04
Conda: 4.43
python: 3.9
opencv-python: 4.5.x,4.6.x

Any progress in this issue?

[likehengqq]

i also have same problem with latest version of opencv-python.If any one was able to solve this issue please reply here.

You can try lowering the Python version.

[bengabp]

Hello guys,please I need help about this. I am getting same error here also and its not allowing video stream to continue.

qt.qpa.plugin: Could not find the Qt platform plugin "wayland" in "/home/bengab/venv/lib/python3.10/site-packages/cv2/qt/plugins

@likehengqq I have also tried decreasing the opencv-python version but its still not working.

[bengabp]

Guys the error shows but it still works. It shows like some kind of warning and it does not prevent my program from running. But when I use ffpyplayer to also read audio the error shows but this time it will not allow my program to run further.

Please what is the cause of this strange behavior?

[asmorkalov]

OpenCV distributes own instance of QT to facilitate imshow and some other UI functions. Own QT built is done without wayland support: https://github.com/opencv/opencv-python/blob/4.x/docker/manylinux2014/Dockerfile_x86_64#L59. I'll take a look if we can add this option to the package for the next release.

[Viha123]

Hello guys,please I need help about this. I am getting same error here also and its not allowing video stream to continue.

qt.qpa.plugin: Could not find the Qt platform plugin "wayland" in "/home/bengab/venv/lib/python3.10/site-packages/cv2/qt/plugins

@likehengqq I have also tried decreasing the opencv-python version but its still not working.

yep similar issue here were you able to figure it out?

[asmorkalov]

Related: https://stackoverflow.com/questions/68417682/qt-and-opencv-app-not-working-in-virtual-environment

[asmorkalov]

@likehengqq @bengabp @KaranParekh11 Could you try to install experimental package with Qr 5.15.8 and Wayland plugin enabled for build: https://github.com/opencv/opencv-python/actions/runs/4012888768? I need feedback from real Wayland-based system.

[asmorkalov]

#784

[vineoak]

I tested out your provided wheel opencv_contrib_python-4.7.0.3564733-cp37-abi3-manylinux_2_17_x86_64.manylinux2014_x86_64.whl with wayland enabled environment and pyqt 5.15.8 installed on Ubuntu 22.04 and can confirm the same output as I now found on your PR #784. Hope this still helps.

qt.qpa.wayland: Failed to load client buffer integration: "wayland-egl"
qt.qpa.wayland: Available client buffer integrations: ()
qt.qpa.wayland: No shell integration named "xdg-shell" found
qt.qpa.wayland: No shell integration named "xdg-shell-v6" found
qt.qpa.wayland: No shell integration named "wl-shell" found
qt.qpa.wayland: No shell integration named "ivi-shell" found
qt.qpa.wayland: Loading shell integration failed.
qt.qpa.wayland: Attempted to load the following shells ("xdg-shell", "xdg-shell-v6", "wl-shell", "ivi-shell")

edit: I can also confirm that the wheel you built works nicely when I change the session to X11.