QCamera can't be displayed in QGraphicsVideoItem

im-red

In the Qt Doc:Camera Overview, it's said:

In C++, your choice depends on whether you are using widgets, or QGraphicsView. The QCameraViewfinder class is used in the widgets case, and QGraphicsVideoItem is useful for QGraphicsView.

I want to display camere image in QGraphicsView, so I write those code:

...
videoItem = new QGraphicsVideoItem;
camera->setViewfinder(videoItem);
videoItem->setSize(QSizeF(100, 100));
videoItem->setPos(0, 0);
videoItem->setAspectRatioMode(Qt::IgnoreAspectRatio);
scene->addItem(videoItem);
camera->setCaptureMode(QCamera::CaptureVideo);
camera->start();
...

but it doesn't work. And if I replace the QGraphicsVideoItem with QCameraViewfinder, it works. (Qt 5.7.0)

SGaist

Hi and welcome to devnet,

Got any error printed ?