Pyside6 Multi threading Opencv Webcam

Question

In the below code I have a Pyside6 application that dynamically creates a list of labels and comboboxes paralel to each other. To the right, each combobox has a list of available cameras and to the left(colored in black) I have a list of labels where in which I want to display the cameras.

• This is what it looks like:

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As I used the currentIndexChanged, whenevever you select any camera device, the thread will be launched and will be displayed at the last label.

Like so:

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What I am struggling with, is:

1. Based on the index of the combobox I want to display the video stream on the same index of the label(as in this example i selected the combo box at index 0 but it displayed in label at index 4)
2. Pass the index of the selected camera(in the individual combobox) to the cv2.VideoCapture(index) so that the user can select what camera they want to display
3. How to be able to multi thread, so as to be able to display multiple cameras at the same time.

Here is the code:

import sys
from PySide6 import QtWidgets
from PySide6.QtCore import Qt, QThread, Signal, Slot
from PySide6.QtGui import QImage
from PySide6.QtGui import QIcon, QPixmap, QImage
from PySide6.QtMultimedia import QMediaDevices
import cv2

class MyWidget(QtWidgets.QWidget):
    def __init__(self):
        super().__init__()

        self.layout = QtWidgets.QGridLayout(self)
        self.lists = ["1", "2", "3"]
        self.availableCameras = []
        self.th = Thread(self)
        self.th.finished.connect(self.close)
        self.th.updateFrame.connect(self.setImage)

        for i in range(5):

            self.label = QtWidgets.QLabel(self)
            self.label.id_number = i
            self.label.setStyleSheet(u"background-color: black;")
            self.layout.addWidget(self.label, i, 0)
            
            self.combobox = QtWidgets.QComboBox(self)
            self.combobox.id_number = i
            self.getAvailableCameras()
            self.combobox.addItems(self.availableCameras)
            self.layout.addWidget(self.combobox, i, 1)
            self.combobox.currentIndexChanged.connect(self.runWebCam)


    @Slot(QImage)
    def runWebCam(self, idx):
        combo = self.sender()
        print(f"Selected the variable {idx} from combo {combo.id_number}")
        self.th.start()

    @Slot(QImage)
    def setImage(self, image):
        self.label.setPixmap(QPixmap.fromImage(image))
    
    def getAvailableCameras(self):
        cameras = QMediaDevices.videoInputs()
        for cameraDevice in cameras:
            self.availableCameras.append(cameraDevice.description())




class Thread(QThread):
    updateFrame = Signal(QImage)
    def __init__(self, parent=None):
        QThread.__init__(self, parent)
        self.status = True
        self.cap = True

    def run(self):
        self.cap = cv2.VideoCapture(0)
        while self.status:
            ret, frame = self.cap.read()
            if not ret:
                continue
            h, w, ch = frame.shape
            img = QImage(frame.data, w, h, ch * w, QImage.Format_RGB888)
            scaled_img = img.scaled(640, 480, Qt.KeepAspectRatio)
            # Emit signal
            self.updateFrame.emit(scaled_img)
        sys.exit(-1)



if __name__ == "__main__":
    app = QtWidgets.QApplication([])

    widget = MyWidget()
    widget.resize(800, 600)
    widget.show()

    sys.exit(app.exec_())

Answer 1

def runWebCam(self, idx):
    self.idx = idx
    combo = self.sender()
    print(f"Selected the variable {idx} from combo {combo.id_number}")
    self.th.start()


def setImage(self, image):
  self.label_list[self.idx].setPixmap(QPixmap.fromImage(image))

'''here self.label is the widget object of last label which you have created.

I tried storing the self.label into a list (self.label_list) and when you are selecting the item in the combo_box getting the idx value Using the above idx value as list index, selecting the right label to display. See the picture attached'''