from PyQt5.QtCore import QDir, Qt, QUrl
from PyQt5.QtMultimedia import QMediaContent, QMediaPlayer
from PyQt5.QtMultimediaWidgets import QVideoWidget
from PyQt5.QtWidgets import (QApplication, QFileDialog, QHBoxLayout, QLabel,
        QPushButton, QSizePolicy, QSlider, QStyle, QVBoxLayout, QWidget)
from PyQt5.QtWidgets import QMainWindow,QWidget, QPushButton, QAction
from PyQt5.QtGui import QIcon


from PyQt5.QtGui     import *
from PyQt5.QtCore    import *
from PyQt5.QtWidgets import *

from PyQt5.QtGui import QPixmap  

from selenium import webdriver
from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.support import expected_conditions as EC
from selenium.webdriver.common.keys import Keys
from selenium.webdriver.common.by import By
import time
import os
import sys

 
class Window(QDialog):
    def __init__(self):
        super().__init__()
        self.title = "Login"
        self.top = 100
        self.left = 100
        self.width = 680
        self.height = 500
        self.InitUI()

    def InitUI(self):
       
        self.setWindowTitle(self.title)
        self.setFixedWidth(250)  
        self.label1 = QLabel('Username')
        self.lineEdit1 = QLineEdit("", self)

        self.label2 = QLabel('Password')
        self.lineEdit2 = QLineEdit("", self)
        
        layoutV = QVBoxLayout()
        self.pushButton = QPushButton(self)
        self.pushButton.setStyleSheet('background-color: rgb(0,0,255); color: #fff')
        self.pushButton.setText('LOGIN')  
        self.pushButton.clicked.connect(self.doLogin)     
       
        
        layoutH1 = QHBoxLayout()
        layoutH1.addWidget(self.label1)
        layoutH1.addWidget(self.lineEdit1)

        layoutH2 = QHBoxLayout()
        layoutH2.addWidget(self.label2)
        layoutH2.addWidget(self.lineEdit2)

        
        layoutV.addLayout(layoutH1)
        layoutV.addLayout(layoutH2)
        layoutV.addWidget(self.pushButton)
        self.setLayout(layoutV)
        self.show()

    def doLogin(self):
        self.cams = Window1('') 
        self.cams.show()
        self.close()


    @pyqtSlot()
    def buttonWindow1_onClick(self):
        self.statusBar().showMessage("Switched to window 1")
        self.cams = Window1(self.lineEdit1.text()) 
        self.cams.show()
        self.close()

    @pyqtSlot()
    def buttonWindow2_onClick(self):
        self.statusBar().showMessage("Switched to window 2")
        self.cams = Window2(self.lineEdit2.text()) 
        self.cams.show()
        self.close()
        
        
class Window1(QDialog):
    def __init__(self, value, parent=None):
        super().__init__(parent)
        self.setWindowTitle('Window1')
        self.setFixedWidth(500)
        self.setFixedHeight(600)
        self.setWindowIcon(self.style().standardIcon(QStyle.SP_FileDialogInfoView))


        self.mediaPlayer = QMediaPlayer(None, QMediaPlayer.VideoSurface) 
        videoWidget = QVideoWidget()
        self.play() 

       
        
        pixmap = QPixmap(os.path.abspath('image.png')) 
        lbl = QLabel(self)                                                                                                                 
        lbl.setPixmap(pixmap) 

      
        with open('message.txt', 'r', encoding="utf-8") as f:
            self.message = f.read()
        lb2 = QLabel(self.message)                                                                                                                 
         



        label1 = QLabel(value)
        self.button = QPushButton()
        self.button.setSizePolicy(QSizePolicy.Minimum, QSizePolicy.Expanding)
        self.button.setIcon(self.style().standardIcon(QStyle.SP_ArrowLeft))
        self.button.setIconSize(QSize(200, 200))
        
        layoutV = QVBoxLayout()
        self.pushButton = QPushButton(self)
        self.pushButton.setStyleSheet('background-color: rgb(0,0,255); color: #fff')
        self.pushButton.setText('Send Now')
        self.pushButton.clicked.connect(self.doSend)
        
        layoutV.addWidget(lbl)
        layoutV.addWidget(lb2) 
        layoutV.addWidget(self.pushButton) 

        layoutV.addWidget(videoWidget) 
        
        self.setLayout(layoutV)
        self.mediaPlayer.setVideoOutput(videoWidget)
        

    def doSend(self):
        driver = webdriver.Chrome()

        driver.get("https://web.whatsapp.com/")
        wait = WebDriverWait(driver, 1000)

        with open('recipients.txt', 'r') as f:
            groups = [group.strip() for group in f.readlines()]

        for group in groups:	 
            #target = '"Dhanya Abhilash"'
            
            target = '"'+group+'"'
            print(target)

            x_arg = '//span[contains(@title,' + target + ')]'
            group_title = wait.until(EC.presence_of_element_located((
                By.XPATH, x_arg)))
            group_title.click()


            inp_xpath = '//div[@contenteditable="true"][@data-tab="10"]'
            input_box = wait.until(EC.presence_of_element_located((
                By.XPATH, inp_xpath)))

            attachment_xpath='//div[@title="Attach"]'
            attachment_box = wait.until(EC.presence_of_element_located((
                By.XPATH, attachment_xpath)))
            attachment_box.click()

            image_xpath='//input[@accept="image/*,video/mp4,video/3gpp,video/quicktime"]'
            image_box = wait.until(EC.presence_of_element_located((
                By.XPATH, image_xpath)))
            image_box.send_keys('E:\\python\\pyqt\\image.png')

            send_xpath='//span[@data-icon="send"]'
            send_button= wait.until(EC.presence_of_element_located((
                By.XPATH, send_xpath)))

            send_button.click()



            inp_xpath1 = '//div[@contenteditable="true"][@data-tab="10"]'
            input_box1 = wait.until(EC.presence_of_element_located((
                By.XPATH, inp_xpath1)))

            attachment_xpath1='//div[@title="Attach"]'
            attachment_box1 = wait.until(EC.presence_of_element_located((
                By.XPATH, attachment_xpath1)))
            attachment_box1.click()

            image_xpath1='//input[@accept="image/*,video/mp4,video/3gpp,video/quicktime"]'
            image_box1 = wait.until(EC.presence_of_element_located((
                By.XPATH, image_xpath1)))
            image_box1.send_keys('E:\\python\\pyqt\\video.mp4')

            send_xpath1='//span[@data-icon="send"]'
            send_button1= wait.until(EC.presence_of_element_located((
                By.XPATH, send_xpath1)))

            send_button1.click()

            
            input_box.send_keys(self.textbox.text() + Keys.ENTER)
            time.sleep(1)


    def play(self):
        fileName='E:/python/pyqt/video.mp4'        
        if fileName != '':
            self.mediaPlayer.setMedia(
                    QMediaContent(QUrl.fromLocalFile(fileName)))
           
        if self.mediaPlayer.state() == QMediaPlayer.PlayingState:
            self.mediaPlayer.pause()
        else:
            self.mediaPlayer.play()        
        
    
class Window2(QDialog):
    def __init__(self, value, parent=None):
        super().__init__(parent)
        self.setWindowTitle('Window2')
        self.setWindowIcon(self.style().standardIcon(QStyle.SP_FileDialogInfoView))

        label1 = QLabel(value)
        self.button = QPushButton()
        self.button.setSizePolicy(QSizePolicy.Minimum, QSizePolicy.Expanding)
        self.button.setIcon(self.style().standardIcon(QStyle.SP_ArrowLeft))
        self.button.setIconSize(QSize(200, 200))
        
        layoutV = QVBoxLayout()
        self.pushButton = QPushButton(self)
        self.pushButton.setStyleSheet('background-color: rgb(0,0,255); color: #fff')
        self.pushButton.setText('Click me!')
        self.pushButton.clicked.connect(self.goMainWindow)
        layoutV.addWidget(self.pushButton)
        
        layoutH = QHBoxLayout()
        layoutH.addWidget(label1)
        layoutH.addWidget(self.button)
        layoutV.addLayout(layoutH)
        self.setLayout(layoutV)

    def goMainWindow(self):
        self.cams = Window()
        self.cams.show()
        self.close()    
        

if __name__ == '__main__':
    app=QApplication(sys.argv)
    ex=Window()
    sys.exit(app.exec_())

Browsing option

from PyQt5.QtCore import QDir, Qt, QUrl
from PyQt5.QtMultimedia import QMediaContent, QMediaPlayer
from PyQt5.QtMultimediaWidgets import QVideoWidget
from PyQt5.QtWidgets import (QApplication, QFileDialog, QHBoxLayout, QLabel,
        QPushButton, QSizePolicy, QSlider, QStyle, QVBoxLayout, QWidget)
from PyQt5.QtWidgets import QMainWindow,QWidget, QPushButton, QAction
from PyQt5.QtGui import QIcon
import sys

class VideoWindow(QMainWindow):

    def __init__(self, parent=None):
        super(VideoWindow, self).__init__(parent)
        self.setWindowTitle("PyQt Video Player Widget Example - pythonprogramminglanguage.com") 

        self.mediaPlayer = QMediaPlayer(None, QMediaPlayer.VideoSurface)

        videoWidget = QVideoWidget()

        self.playButton = QPushButton()
        self.playButton.setEnabled(False)
        self.playButton.setIcon(self.style().standardIcon(QStyle.SP_MediaPlay))
        self.playButton.clicked.connect(self.play)

        self.positionSlider = QSlider(Qt.Horizontal)
        self.positionSlider.setRange(0, 0)
        self.positionSlider.sliderMoved.connect(self.setPosition)

        self.errorLabel = QLabel()
        self.errorLabel.setSizePolicy(QSizePolicy.Preferred,
                QSizePolicy.Maximum)

        # Create new action
        openAction = QAction(QIcon('open.png'), '&Open', self)        
        openAction.setShortcut('Ctrl+O')
        openAction.setStatusTip('Open movie')
        openAction.triggered.connect(self.openFile)

        # Create exit action
        exitAction = QAction(QIcon('exit.png'), '&Exit', self)        
        exitAction.setShortcut('Ctrl+Q')
        exitAction.setStatusTip('Exit application')
        exitAction.triggered.connect(self.exitCall)

        # Create menu bar and add action
        menuBar = self.menuBar()
        fileMenu = menuBar.addMenu('&File')
        #fileMenu.addAction(newAction)
        fileMenu.addAction(openAction)
        fileMenu.addAction(exitAction)

        # Create a widget for window contents
        wid = QWidget(self)
        self.setCentralWidget(wid)

        # Create layouts to place inside widget
        controlLayout = QHBoxLayout()
        controlLayout.setContentsMargins(0, 0, 0, 0)
        controlLayout.addWidget(self.playButton)
        controlLayout.addWidget(self.positionSlider)

        layout = QVBoxLayout()
        layout.addWidget(videoWidget)
        layout.addLayout(controlLayout)
        layout.addWidget(self.errorLabel)

        # Set widget to contain window contents
        wid.setLayout(layout)

        self.mediaPlayer.setVideoOutput(videoWidget)
        self.mediaPlayer.stateChanged.connect(self.mediaStateChanged)
        self.mediaPlayer.positionChanged.connect(self.positionChanged)
        self.mediaPlayer.durationChanged.connect(self.durationChanged)
        self.mediaPlayer.error.connect(self.handleError)

    def openFile(self):
        fileName, _ = QFileDialog.getOpenFileName(self, "Open Movie",
                QDir.homePath())

        if fileName != '':
            self.mediaPlayer.setMedia(
                    QMediaContent(QUrl.fromLocalFile(fileName)))
            self.playButton.setEnabled(True)

    def exitCall(self):
        sys.exit(app.exec_())

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

    def mediaStateChanged(self, state):
        if self.mediaPlayer.state() == QMediaPlayer.PlayingState:
            self.playButton.setIcon(
                    self.style().standardIcon(QStyle.SP_MediaPause))
        else:
            self.playButton.setIcon(
                    self.style().standardIcon(QStyle.SP_MediaPlay))

    def positionChanged(self, position):
        self.positionSlider.setValue(position)

    def durationChanged(self, duration):
        self.positionSlider.setRange(0, duration)

    def setPosition(self, position):
        self.mediaPlayer.setPosition(position)

    def handleError(self):
        self.playButton.setEnabled(False)
        self.errorLabel.setText("Error: " + self.mediaPlayer.errorString())

if __name__ == '__main__':
    app = QApplication(sys.argv)
    player = VideoWindow()
    player.resize(640, 480)
    player.show()
    sys.exit(app.exec_())