Setting VideoOutput source programmatically

Shiba

Hello,

I'm having trouble setting the source of a VideoOutput component programmatically. My QCamera gets instantiated dynamically and isn't defined in a QML file instead it is defined an C++ file. Am I doing something wrong?

Header file

class MainController : public QObject
{
    Q_OBJECT
    Q_PROPERTY(QCamera* cam READ getCamera() CONSTANT)
public:
    explicit MainController(QObject *layout = nullptr
			    , QObject *parent = nullptr);
    ~MainController();
    Q_INVOKABLE QCamera* getCamera();
public slots:
    Q_INVOKABLE void buttonClicked();
};

Main

int main(int argc, char *argv[])
{
    QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
    QGuiApplication app(argc, argv);

    QQmlApplicationEngine engine;

    MainController controller;
    engine.rootContext()->setContextProperty("controller"
				             , &controller);

    engine.load(QUrl(QLatin1String("qrc:/main.qml")));
    if (engine.rootObjects().isEmpty())
        return -1;

    return app.exec();
}

QML

import QtQuick 2.7
import QtQuick.Controls 2.0
import QtQuick.Layouts 1.3
import QtMultimedia 5.8

    Rectangle
{
	id: rect
	height: 480
        width: 640
        color: "grey"
        anchors.centerIn: parent

        /*
        Camera
        {
            id: camera
            objectName: "camera"
            captureMode: Camera.CaptureViewfinder
            viewfinder.maximumFrameRate: 25.0
            viewfinder.minimumFrameRate: 25.0
            viewfinder.resolution: "640x480"
        }
        */

        VideoOutput
        {
        	id: viewFinder
        	objectName: "viewFinder"
        	anchors.fill: parent
         	focus : visible
        	source: controller.cam
	}
}

I've tested it with the Camera defined in QML and that just works.

mranger90

You can't just assign the source to a QCamera.
Bear in mind that QDeclarative:Camera is not a QCamera.
What you need to do is similar to this:
https://forum.qt.io/topic/27196/use-qml-videooutput-item-with-c-qmediaplayer

Put your QCamera in the mediaplayer object and set the viewFinder to the surface.

I have some code that works in this manner.

Shiba

@mranger90 Thanks!