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]

https://github.com/opencv/opencv-python/pull/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.

[asmorkalov]

Thanks. I got the same result with Kubuntu 22.04. It looks like I missed something in package.

[mahyarmirrashed]

Is there any way to silence this message for now in the terminal?

[Petros626]

@mahyarmirrashed yes it is. So there 3 ways I 've proven to work to suppress this message:

1. use os.environ.pop("QT_QPA_PLATFORM_PLUGIN_PATH") after import cv2
2. try sudo pip install opencv-python-headless
3. delete the libqxcb frm OpenCV in /home/yourname/.local/lib/python3.9/site-packages/cv2/qt/plugins/platforms

In the Thonny IDE commen in no. 1 works fine should in terminal too.

[jeroenvermunt]

I am on Wayland and seeing the same result as @vineoak, is there a solution without having to swich to X11?

[asmorkalov]

Not yet for now.

[git-sparrowlinux]

disable wayland in ubuntu system

go to /etc/gdm3/custom.conf and uncomment the "WaylandEnable=false"

Uncomment the line below to force the login screen to use Xorg WaylandEnable=false

then restart the PC

[MasterHM-ml]

2. try sudo pip install opencv-python-headless

second option worked for me. thanks

[MeqdadDev]

Same issue here, but the code itself is working fine. I've tried @ultimateagain steps and disabled this warning message.

Environment: OS: Ubuntu 22.04 Python: v3.10.12

[jwillikers]

I am on Wayland and seeing the same result as @vineoak, is there a solution without having to swich to X11?

@jeroenvermunt, setting QT_QPA_PLATFORM=xcb when running OpenCV should launch under XWayland without requiring you to switch your session over to X11.

[rouftom]

Try this:

import os
os.environ["QT_QPA_PLATFORM_PLUGIN_PATH"] = "wayland"

[MasterHM-ml]

QT_QPA_PLATFORM=xcb

If you're not in conda environment, this solution will work best

pip3 install opencv_python
export QT_QPA_PLATFORM=xcb

this will work best in the current on terminal only. For permanent change do

echo "export QT_QPA_PLATFORM=xcb" >> ~/.profile

and restart/logout

[mak448a]

I am on Wayland and seeing the same result as @vineoak, is there a solution without having to swich to X11?

@jeroenvermunt, setting QT_QPA_PLATFORM=xcb when running OpenCV should launch under XWayland without requiring you to switch your session over to X11.

It works!

[golfinq]

A workaround I found was to use xwayland-run which spawns an xwayland instance for opencv to run in. I did it with QT_QPA_PLATFORM=xcb xwayland-run -- pipenv run python ... where pipenv installed opencv-python, opencv-contrib-python, and opencv-python-headless into a virtual environment

[Avasam]

Could be related, if not the exact same issue, since the problem is with bundled QT: https://bugreports.qt.io/browse/QTBUG-114635

[EnziinSystem]

@mahyarmirrashed yes it is. So there 3 ways I 've proven to work to suppress this message:

1. use os.environ.pop("QT_QPA_PLATFORM_PLUGIN_PATH") after import cv2
2. try sudo pip install opencv-python-headless
3. delete the libqxcb frm OpenCV in /home/yourname/.local/lib/python3.9/site-packages/cv2/qt/plugins/platforms

In the Thonny IDE commen in no. 1 works fine should in terminal too.

The problem is that opencv-python does not come with a library for Wayland so QT_QPA_PLATFORM_PLUGIN_PATH has no value and does not point to any location.

Therefore, your method does not solve the problem on systems operating based on Wayland such as Raspberry Pi-5.

$ ls .local/lib/python3.11/site-packages/opencv_python.libs
libavcodec-03bb4e36.so.59.37.100   libQt5Test-32fc1c2a.so.5.15.0      libxcb-icccm-05fb8c7f.so.4.0.0        libxcb-util-c74d156a.so.1.0.0
libavformat-1279b9be.so.59.27.100  libQt5Widgets-b1296c1e.so.5.15.0   libxcb-image-75825d2e.so.0.0.0        libxcb-xfixes-f4cf71d4.so.0.0.0
libavutil-f0a93969.so.57.28.100    libQt5XcbQpa-7b9d0389.so.5.15.0    libxcb-keysyms-73cd270d.so.1.0.0      libxcb-xinerama-6372573d.so.0.0.0
libcrypto-956af892.so.1.1          libssl-b9692d76.so.1.1             libxcb-randr-e1606dfc.so.0.1.0        libxcb-xkb-e2f6f9de.so.1.0.0
libgfortran-8634ef04.so.3.0.0      libswresample-39e38dfb.so.4.7.100  libxcb-render-76b15fe5.so.0.0.0       libxkbcommon-e272a37d.so.0.0.0
libopenblas-r0-8966572e.3.3.so     libswscale-86dc6859.so.6.7.100     libxcb-render-util-486ef3ee.so.0.0.0  libxkbcommon-x11-b76c7d31.so.0.0.0
libpng16-45e47e2f.so.16.40.0       libvpx-b07bc8cf.so.8.0.1           libxcb-shape-e8fe4bc4.so.0.0.0
libQt5Core-9e162752.so.5.15.0      libX11-xcb-8ab4be54.so.1.0.0       libxcb-shm-cad72500.so.0.0.0
libQt5Gui-08f6a1f3.so.5.15.0       libXau-21870672.so.6.0.0           libxcb-sync-dc271c48.so.1.0.0

There is no Wayland library.

RUN curl -C - -O -L https://download.qt.io/official_releases/qt/5.15/${QT_VERSION}/single/qt-everywhere-src-${QT_VERSION}.tar.xz && \
    tar -xf qt-everywhere-src-${QT_VERSION}.tar.xz && \
    cd qt-everywhere-src-${QT_VERSION} && \
    export MAKEFLAGS=-j$(nproc) && \
    ./configure -prefix /opt/Qt${QT_VERSION} -release -opensource -confirm-license -qtnamespace QtOpenCVPython -xcb -xcb-xlib -bundled-xcb-xinput -no-openssl -no-dbus -skip qt3d -skip qtactiveqt -skip qtcanvas3d -skip qtconnectivity -skip qtdatavis3d -skip qtdoc -skip qtgamepad -skip qtgraphicaleffects -skip qtimageformats -skip qtlocation -skip qtmultimedia -skip qtpurchasing -skip qtqa -skip qtremoteobjects -skip qtrepotools -skip qtscript -skip qtscxml -skip qtsensors -skip qtserialbus -skip qtserialport -skip qtspeech -skip translations \
 -skip qtwayland \
-skip qtwebchannel -skip qtwebengine -skip qtwebsockets -skip qtwebview -skip xmlpatterns -skip declarative -make libs && \
    make && \
    make install && \
    cd .. && \
    rm -rf qt-everywhere*

The deeper cause lies in the Dockerfile build operation, which ignored the Wayland build "-skip qtwayland"