#include <QtWidgets>
#include <QVideoWidget>
#include <QCamera>
#include <QCameraInfo>
#include <QCameraImageProcessingControl>

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);

    auto camera = new QCamera(new QCamera(QCameraInfo::defaultCamera()));

    // Uncomment the following lines to verify video displays
    // however they are not required to produce the error output
//    auto *surface = new QVideoWidget;
//    surface->resize(400,240);
//    surface->show();
//    camera->setViewfinder(surface);

    camera->start();
    camera->imageProcessing()->setContrast(0.5);


    return app.exec();
};