QGraphicsView 中的 QGraphicsVideoItem

Question

I am trying to draw video inside QGraphicsView in QT5.5. Here's the code

QString path = "video.mp4";

qDebug() << QFile::exists(path);

ui->graphicsView->setScene(new QGraphicsScene());

QMediaPlayer pl;
QGraphicsVideoItem vid;
pl.setVideoOutput(&vid);
qDebug() << pl.error();

vid.setSize( QSizeF(1920, 1080) );

pl.setMedia( QUrl::fromLocalFile( path ) );
qDebug() << pl.error();

ui->graphicsView->scene()->addItem(&vid);
ui->graphicsView->resize(1920, 1080);
pl.play();
qDebug() << pl.error();

Nothing is drawn. No errors. File exists. Maybe some issue with plugins? Or hardware acceleration, cause I am on notebook with discrete card. Thank you in advance.

Answer 1

Ok, I got it. My stupid mistake. QMediaPlayer and QGraphicsVideoItem was deleted after exiting scope.

Answer 2

In case someone else runs into this page. You may have to use a QVideoWidget instead of a QGraphicsVideoItem.

https://whynhow.info/30713/How-to-make-friends-QCamera-and-QGraphicsVideoItem

    // Note: QGraphicsVideoItem doesn't work but QVideoWidget does
    // https://whynhow.info/30713/How-to-make-friends-QCamera-and-QGraphicsVideoItem?
    auto *vidWidget = new QVideoWidget;
    mpScene->addWidget(vidWidget);

    mpCamera = new QCamera(acCamera, this);
    mpCamera->setViewfinder(vidWidget);
    mpCamera->setCaptureMode(QCamera::CaptureVideo);