How to draw QtGraphicsView on Top of QVideoWidget with transparency

Question

I am trying to overlay some graphics(QtGraphicsView) on top of video player(QVideoWidget). i have already tried setting QtGraphicsView subclass stylesheets to transparent an

Answer 1

One possible solution is to use QGraphicsVideoItem instead of QVideoWidget and embed it in the QGraphicsView, then the other items can be made child of the QGraphicsVideoItem so that it is on top, besides the position of the new items will be related to the QGraphicsVideoItem.

import os
from PyQt5 import QtCore, QtGui, QtWidgets, QtMultimedia, QtMultimediaWidgets

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._videoitem = QtMultimediaWidgets.QGraphicsVideoItem()
        self._scene.addItem(self._videoitem)
        self._ellipse_item = QtWidgets.QGraphicsEllipseItem(QtCore.QRectF(50, 50, 40, 40), self._videoitem)
        self._ellipse_item.setBrush(QtGui.QBrush(QtCore.Qt.green))
        self._ellipse_item.setPen(QtGui.QPen(QtCore.Qt.red))

        self._player = QtMultimedia.QMediaPlayer(self, QtMultimedia.QMediaPlayer.VideoSurface)
        self._player.stateChanged.connect(self.on_stateChanged)
        self._player.setVideoOutput(self._videoitem)

        file = os.path.join(os.path.dirname(__file__), "small.mp4")
        self._player.setMedia(QtMultimedia.QMediaContent(QtCore.QUrl.fromLocalFile(file)))
        button = QtWidgets.QPushButton("Play")
        button.clicked.connect(self._player.play)

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

    @QtCore.pyqtSlot(QtMultimedia.QMediaPlayer.State)
    def on_stateChanged(self, state):
        if state == QtMultimedia.QMediaPlayer.PlayingState:
            self._gv.fitInView(self._videoitem, QtCore.Qt.KeepAspectRatio)

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