failed to start because no Qt platform plugin could be initialized

[HasarinduPerera]

Environment : / 环境

• OS: Ubuntu 20.04.6 LTS
• Python 3.8 X64
• PyQt5 [e.g. 5.10.1]

import cv2
from PyQt5.QtWidgets import QApplication, QLabel, QMainWindow
from PyQt5.QtGui import QImage, QPixmap
from PyQt5.QtCore import Qt, QTimer
from PyQt5 import QtCore

class VideoWindow(QMainWindow):
    def __init__(self):
        super().__init__()
        self.setWindowState(Qt.WindowFullScreen)  # Set fullscreen mode

        # Create a label to display the video stream
        self.label = QLabel(self)
        self.setCentralWidget(self.label)

        # Initialize the video capture
        self.cap = cv2.VideoCapture(0)
        self.cap.set(cv2.CAP_PROP_FRAME_WIDTH, 320)
        self.cap.set(cv2.CAP_PROP_FRAME_HEIGHT, 187)

        # Start updating the frame
        self.update_frame()

    def resizeEvent(self, event):
        # Adjust the label size to fit the window
        self.label.setGeometry(0, 0, event.size().width(), event.size().height())

    def update_frame(self):
        # Get the frame from the video capture
        ret, frame = self.cap.read()

        if ret:
            # Convert the OpenCV BGR frame to RGB
            frame = cv2.cvtColor(frame, cv2.COLOR_BGR2RGB)

            # Rotate the frame by 90 degrees
            frame = cv2.rotate(frame, cv2.ROTATE_90_COUNTERCLOCKWISE)

            # Resize the frame to fit the window size
            resized_frame = cv2.resize(frame, (self.label.width(), self.label.height()))

            # Convert the resized frame to QImage format
            image = QImage(resized_frame.data, resized_frame.shape[1], resized_frame.shape[0], QImage.Format_RGB888)

            # Convert QImage to QPixmap
            pixmap = QPixmap.fromImage(image)

            # Update the label with the new pixmap
            self.label.setPixmap(pixmap)

        # Schedule the next frame update
        QtCore.QTimer.singleShot(1, self.update_frame)

if __name__ == "__main__":
    # Create the QApplication
    app = QApplication([])

    # Create the VideoWindow
    window = VideoWindow()
    window.showFullScreen()

    # Start the QApplication event loop
    app.exec_()

    # Release the video capture
    window.cap.release()

I am trying to run this code but it gives an error, I tried reinstalling, exporting plugin variable, but nothing works.

QObject::moveToThread: Current thread (0x1100d810) is not the object's thread (0x11517c30).
Cannot move to target thread (0x1100d810)

qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "/home/user/.local/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.

Aborted

TIA

[892768447]

export QT_DEBUG_PLUGINS=1 before run python script. maybe see some missing dependency libraries about xcb

[HasarinduPerera]

This was the result. Any suggestions? (The result was very long, this is the only part regarding xcb and also the last part)

TIA

QFactoryLoader::QFactoryLoader() looking at "/usr/lib/aarch64-linux-gnu/qt5/plugins/platforms/libqxcb.so"
Found metadata in lib /usr/lib/aarch64-linux-gnu/qt5/plugins/platforms/libqxcb.so, metadata=
{
    "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
    "MetaData": {
        "Keys": [
            "xcb"
        ]
    },
    "archreq": 0,
    "className": "QXcbIntegrationPlugin",
    "debug": false,
    "version": 331520
}


Got keys from plugin meta data ("xcb")
QFactoryLoader::QFactoryLoader() checking directory path "/usr/bin/platforms" ...
loaded library "/home/user/.local/lib/python3.9/site-packages/cv2/qt/plugins/platforms/libqxcb.so"
QObject::moveToThread: Current thread (0x3a4f250) is not the object's thread (0x3f5dbe0).
Cannot move to target thread (0x3a4f250)

qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "/home/user/.local/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.

Aborted

[892768447]

maybe different version Qtxcb problem

loaded library "/home/user/.local/lib/python3.9/site-packages/cv2/qt/plugins/platforms/libqxcb.so"

/usr/lib/aarch64-linux-gnu/qt5/plugins/platforms/libqxcb.so, metadata=

[892768447]

Normally, PyQt5 will use the plugin library in its own directory.

check your environment variable in your python scripts at first.

import os print(os.environ.get('PATH')) print(os.environ.get('LD_LIBRARY_PATH'))