Pyqt Video Frame Update Signal (trigger Function After Each Video Frame)

I am creating a video player and I need to draw some polygons on top of it. I am using a QGraphicsScene to create this and I need to update the polygons on screen after each frame.

Solution 1:

There are 2 options:

• positionChanged is emited every second because the notifyInterval property of QMediaPlayer is set in that period. So you can change that property, for example to 60 ms.

---

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

class MainWindow(QtWidgets.QMainWindow):
    def __init__(self, parent=None):
        super(MainWindow, self).__init__(parent)
        scene = QtWidgets.QGraphicsScene(self)
        self.video_view = QtWidgets.QGraphicsView(scene)
        self.setCentralWidget(self.video_view)

        self.player = QtMultimedia.QMediaPlayer(self, QtMultimedia.QMediaPlayer.VideoSurface)
        self.video_item = QtMultimediaWidgets.QGraphicsVideoItem()
        self.player.setVideoOutput(self.video_item)
        scene.addItem(self.video_item)
        file = "/path/of/video"
        self.player.setMedia(QtMultimedia.QMediaContent(QtCore.QUrl.fromLocalFile(file)))
        self.player.positionChanged.connect(self.on_positionChanged)
        self.player.setNotifyInterval(60)
        self.player.play()

    @QtCore.pyqtSlot('qint64')
    def on_positionChanged(self, p):
        print(p, QtCore.QTime.currentTime().toString("hh:mm:ss.zzz"))

if __name__ == '__main__':
    import sys
    app = QtWidgets.QApplication(sys.argv)
    w = MainWindow()
    w.resize(640, 480)
    w.show()
    sys.exit(app.exec_())

• Use the VideoFrameProbed signal from QVideoProbe:

---

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

class MainWindow(QtWidgets.QMainWindow):
    def __init__(self, parent=None):
        super(MainWindow, self).__init__(parent)
        scene = QtWidgets.QGraphicsScene(self)
        self.video_view = QtWidgets.QGraphicsView(scene)
        self.setCentralWidget(self.video_view)

        self.player = QtMultimedia.QMediaPlayer(self, QtMultimedia.QMediaPlayer.VideoSurface)
        self.video_item = QtMultimediaWidgets.QGraphicsVideoItem()
        self.player.setVideoOutput(self.video_item)
        scene.addItem(self.video_item)
        file = "/path/of/video"
        self.player.setMedia(QtMultimedia.QMediaContent(QtCore.QUrl.fromLocalFile(file)))
        self.player.play()

        probe = QtMultimedia.QVideoProbe(self)
        probe.videoFrameProbed.connect(self.on_videoFrameProbed)
        probe.setSource(self.player)

    @QtCore.pyqtSlot()
    def on_videoFrameProbed(self):
        print(QtCore.QTime.currentTime().toString("hh:mm:ss.zzz"))

if __name__ == '__main__':
    import sys
    app = QtWidgets.QApplication(sys.argv)
    w = MainWindow()
    w.resize(640, 480)
    w.show()
    sys.exit(app.exec_())