Interaction between QGraphicsVideoItem, QGraphicsScene, QGraphicsView

Sierra

Hello All,

it is the first time that I interface with the world of scenes and views. I've read some theory, and now I'm doing some experiments to better understand how to use it all.

I created this simple example:

int main(int argc, char *argv[])
{
    QApplication::setAttribute(Qt::AA_ShareOpenGLContexts, true);
    QApplication a(argc, argv);

    QString url = "gst-pipeline: videotestsrc ! xvimagesink name=\"qtvideosink\"";

    QGraphicsVideoItem* item = new QGraphicsVideoItem;
    item->setSize(QSizeF(500, 480));

    QMediaPlayer p;
    p.setVideoOutput(item);
    p.setMedia(QMediaContent()); //discard
    p.setMedia(QUrl(url));
    p.play();

    QGraphicsScene* scene = new QGraphicsScene;
    QGraphicsRectItem *rect = scene->addRect( 10,10, 50, 70, QPen(Qt::black), QBrush(Qt::red));
    rect->setFlag(QGraphicsItem::ItemIsMovable);

    QGraphicsView view(scene);
    view.scene()->addItem(item);
    view.show();

    return a.exec();
}

But what I get is not as imagined:

As you can see from the image above, I get two windows, one containing View and Scene, and a second one containing the VideoItem.
Could you please tell me what/where I'm doing wrong?

Qt: 5.15.2, OS: Debian 12

Thanks

Pl45m4

@Sierra said in Interaction between QGraphicsVideoItem, QGraphicsScene, QGraphicsView:

Could you please tell me what/where I'm doing wrong?

When you tell us, what you want to do or what you expect... :)

You have your QMediaPlayer with your video in one window and your QGraphicsView + -scene with your red rect in another widget.

Asperamanca

I suspect you must not call "play()" until the QGraphicsView is ready.
Look at the order of calls in the doc's example

JoeCFD

I guess you may need to create a qwidget and add a layout(QHBoxlayout) to it. Then add item and view to the layout.

Sierra

@Pl45m4 What I would like to get is the QMediaPlayer "contained inside" the QGraphicsVideoItem, and the latter QGraphicsVideoItem "contained inside" the same schene where is the red rect.