Qt6 QML Loader doesn't work with CaptureSession

charlie2024

This has been driving me crazy for a few days now. For some reason, I cannot get Camera to work with Loader. I want dynamic loading because the underlying video device can be fickle, and I'd like the UI to automatically recover from it.

Here is the code:

import QtQuick 2.15
import QtMultimedia 6.6
import QtQuick.Controls 2.12
import "../../shared"

Item {
    property string cameraDeviceName
    property var selectedDevice 

    MediaDevices {
        id: mediaDevices
    }

    // Loader {
    //     id: captureSessionLoader
    //     active: true
    //     sourceComponent: captureSessionComponent 
    //     onLoaded: {
    //       console.log("Component loaded:", captureSessionLoader.sourceComponent == captureSessionComponent ? "Capture Session" : "Empty Component");
    //     }
    // }

    // Component {
    //     id: captureSessionComponent
        CaptureSession {
            camera: Camera {
                id: camera
                cameraDevice: mediaDevices.videoInputs[0]
                active: true
                onErrorOccurred: {
                    console.log("Camera object has some error", errorString)
                }
            }

            videoOutput: videoOutput
        }
    // }

    VideoOutput {
        id: videoOutput
        anchors.fill: parent
    }
}

Here is what I am trying to figure out:

If I comment out the Loader code, and start the UI, the camera shows up fine.
If I uncomment the Loader code, and start the UI, nothing shows up on the screen.
I tried replace CaptureSession with a simple rectangle, it would show up on the screen fine.

So apparently something is wrong with Loader working with CaptureSession, but I cannot figure out what. I do not see any errors being printed out on the console. And I do see Component loaded every time I start the UI, so it's not an issue with not loader not loading.

Thanks for any comments!