pyqt5实现两个摄像头监控

要实现两个摄像头监控，可以使用PyQt5中的QCamera和QCameraViewfinder模块。下面是一个简单的示例代码：

from PyQt5.QtCore import Qt
from PyQt5.QtWidgets import QApplication, QWidget, QVBoxLayout, QHBoxLayout, QLabel
from PyQt5.QtMultimedia import QCamera, QCameraViewfinder, QCameraInfo

class CameraWidget(QWidget):
    def __init__(self, camera):
        super().__init__()
        
        self.camera = camera
        self.viewfinder = QCameraViewfinder()
        self.viewfinder.setAspectRatioMode(Qt.KeepAspectRatio)
        self.viewfinder.setMinimumSize(640, 480)
        
        layout = QVBoxLayout(self)
        layout.addWidget(self.viewfinder)
        
        self.setLayout(layout)
        
        self.camera.setViewfinder(self.viewfinder)
        self.camera.start()

class MainWindow(QWidget):
    def __init__(self):
        super().__init__()

        self.setWindowTitle('Camera Monitor')
        
        cameras = QCameraInfo.availableCameras()
        
        if len(cameras) < 2:
            self.errorMessage = QLabel(self)
            self.errorMessage.setText('Two cameras are required to run this application.')
            return
        
        self.camera1 = QCamera(cameras[0])
        self.camera2 = QCamera(cameras[1])
        
        self.camera1Widget = CameraWidget(self.camera1)
        self.camera2Widget = CameraWidget(self.camera2)
        
        layout = QHBoxLayout(self)
        layout.addWidget(self.camera1Widget)
        layout.addWidget(self.camera2Widget)
        
        self.setLayout(layout)

if __name__ == '__main__':
    app = QApplication([])
    window = MainWindow()
    window.show()
    app.exec_()

这个示例代码会打开两个摄像头，并将它们实时监控的画面显示在两个QCameraViewfinder中。如果你只有一个摄像头，可以将代码中的`len(cameras) < 2`改为`len(cameras) < 1`，并使用一个QCamera对象即可。