using QOpenGLWidget as viewPort for QGraphicsView

[Sh.m.z]

Re: using QOpenGLWidget as viewPort for QGraphicsView in Scene doesn't work?

I had the same problem mentioned by @davecotter, but by using the graphicsView->setViewport(new QOpenGLWidget()) after the mediaPlayer->setMedia(...) the problem is resolved.
However, I still have a performance problem in playing video using QGraphicsView and QGraphicsVideoItem. It uses 70% of the CPU to just play a MP4 video (1920x1080).
While, if I substitute the QGraphicsView with a QVideoWidget, the CPU usage drastically drops to ~6%.
However, the problem is that I have to use a QGraphicsView to play the video because I need to draw some lines and texts over the video based on the user's mouse clicks.
My OS is macOS 10.15.7 and I am using PyQt5 version 5.15.2. I would appreciate it if someone please help me to know why there is such a difference between the performance of QVideoWidget and QGraphicsVideoItem.
Is there any particular setting in the QGraphicsVideoItem to improve its rendering performance?
It could help me to solve this problem.

[SGaist]

Hi,

What machine are you running ?

Are you testing that with a minimal application ?

[Sh.m.z]

Hi,
Thanks for your reply.
I am running the application on MacBook Pro (Retina), 2.4 GHz Dual-Core Intel Core i5 processor, 8 GB 1600 MHz DDR3 memory with Intel Iris 1536 MB graphics.
It is a minimal application that has only a QGaphicsView to play a full HD video.

[SGaist]

Do you have a discrete GPU on that machine ?

[Sh.m.z]

No, I do not have any discrete GPU.

[Sh.m.z]

This is the sample code I used from https://stackoverflow.com/questions/53899740/how-to-draw-qtgraphicsview-on-top-of-qvideowidget-with-transparency.

class Widget(QtWidgets.QWidget):
    def __init__(self, parent=None):
        super(Widget, self).__init__(parent)

        self._scene = QtWidgets.QGraphicsScene(self)

        self._gv = QtWidgets.QGraphicsView(self._scene)
        self._gv.setBackgroundBrush(QtGui.QBrush(QtCore.Qt.lightGray))

        self._videoitem = QGraphicsVideoItem() 
        self._scene.addItem(self._videoitem)

        self._player = QMediaPlayer(self, QMediaPlayer.VideoSurface)
        self._player.setVideoOutput(self._videoitem.videoSurface())
        file = os.path.join(os.path.dirname(__file__), "GOPR0196.MP4")
        self._player.setMedia(QMediaContent(QtCore.QUrl.fromLocalFile(file)))

        button = QtWidgets.QPushButton("Play")
        button.clicked.connect(self.play)

        self.resize(640, 480)
        lay = QtWidgets.QVBoxLayout(self)
        lay.addWidget(self._gv)
        lay.addWidget(button)

    def play(self):
        oglWidget = QOpenGLWidget()
        self._gv.setViewport(oglWidget)

        if self._player.state() == QMediaPlayer.PlayingState:
            self._player.pause()
        else:
            self._player.play()

if __name__ == '__main__':
    import sys
    app = QtWidgets.QApplication(sys.argv)
    w = Widget()
    w.show()
    sys.exit(app.exec_())