////////////////////////////////////////////////mainwindow.h
#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include <QtCore>
#include <QtGui>
#include <QMediaPlayer>
#include <QFileDialog>
#include <QGraphicsScene>
#include <QGraphicsVideoItem>
#include "mygraphicsview.h"



namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    explicit MainWindow(QWidget *parent = nullptr);
    ~MainWindow();

private slots:
    void on_actionOpen_triggered();

private:
    Ui::MainWindow *ui;
    QGraphicsScene *scene;
    QGraphicsVideoItem *videoItem;
    QMediaPlayer* mediaPlayer;

    bool rectExist = false;
};

#endif // MAINWINDOW_H

////////////////////////////////////////////////mainwindow.cpp
#include "mainwindow.h"
#include "ui_mainwindow.h"

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    mediaPlayer = new QMediaPlayer(this);
    videoItem = new QGraphicsVideoItem;
    scene = new QGraphicsScene(this);
    ui->graphicsView->setScene(scene);
    mediaPlayer->setVideoOutput(videoItem);
    ui->graphicsView->scene()->addItem(videoItem);
    ui->graphicsView->show();


}

MainWindow::~MainWindow()
{
    delete ui;
}

void MainWindow::on_actionOpen_triggered()
{
    QString fileName = QFileDialog::getOpenFileName(this,"Select Video","","video Files (*.mp4)");

        mediaPlayer->stop();
        mediaPlayer->setMedia(QUrl::fromLocalFile(fileName));
        mediaPlayer->play();
}


//mainwindow.cpp