How to play video in a QVideoWidget promoted in Qt Designer?

I am a beginner in Qt. But following some tutorials I created a UI in qt designer which would display a live stream video. I have read that in order to add video i need to promote widget to a QVideoWidget. Then I convert the .ui to a .py file to access it using python language. The thing is once i have done that i dont know how to put the video in the widget that i made in the ui. Thank you.

The code below show the GUI.py file. I am importing it in another file where I would code it show the video. but dont know how thanks

# -*- coding: utf-8 -*-

# Form implementation generated from reading ui file 'facebio.ui'
#
# Created by: PyQt5 UI code generator 5.6
#
# WARNING! All changes made in this file will be lost!

from PyQt5 import QtCore, QtGui, QtWidgets

class Ui_MainWindow(object):
    def setupUi(self, MainWindow):
        MainWindow.setObjectName("MainWindow")
        MainWindow.resize(558, 388)
        self.centralwidget = QtWidgets.QWidget(MainWindow)
        self.centralwidget.setObjectName("centralwidget")
        self.listWidget = QtWidgets.QListWidget(self.centralwidget)
        self.listWidget.setGeometry(QtCore.QRect(280, 10, 261, 221))
        self.listWidget.setObjectName("listWidget")
        self.listWidget_2 = QtWidgets.QListWidget(self.centralwidget)
        self.listWidget_2.setGeometry(QtCore.QRect(20, 240, 521, 101))
        self.listWidget_2.setObjectName("listWidget_2")
        self.widget = QVideoWidget(self.centralwidget)
        self.widget.setGeometry(QtCore.QRect(20, 10, 241, 221))
        self.widget.setObjectName("widget")
        MainWindow.setCentralWidget(self.centralwidget)

        self.retranslateUi(MainWindow)
        QtCore.QMetaObject.connectSlotsByName(MainWindow)

    def retranslateUi(self, MainWindow):
        _translate = QtCore.QCoreApplication.translate
        MainWindow.setWindowTitle(_translate("MainWindow", "MainWindow"))

from PyQt5.QtMultimediaWidgets import QVideoWidget

if __name__ == "__main__":
    import sys
    app = QtWidgets.QApplication(sys.argv)
    MainWindow = QtWidgets.QMainWindow()
    ui = Ui_MainWindow()
    ui.setupUi(MainWindow)
    MainWindow.show()
    sys.exit(app.exec_())

You only have to inherit from the widget selected in Qt Designer and use the generated design, then use a QMediaPlayer and then set it to the QVideoWidget:

main.py

from PyQt5 import QtCore, QtGui, QtWidgets, QtMultimedia

from GUI import Ui_MainWindow

class MainWindow(QtWidgets.QMainWindow, Ui_MainWindow):
    def __init__(self, *args, **kwargs):
        QtWidgets.QMainWindow.__init__(self, *args, **kwargs)
        self.setupUi(self)

        self.mediaPlayer = QtMultimedia.QMediaPlayer(self)
        self.mediaPlayer.setVideoOutput(self.widget)
        # fileName = "/path/of/your/local_file"
        # url = QtCore.QUrl.fromLocalFile(fileName)
        url = QtCore.QUrl("http://clips.vorwaerts-gmbh.de/VfE_html5.mp4")
        self.mediaPlayer.setMedia(QtMultimedia.QMediaContent(url))
        self.mediaPlayer.play()

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