QVideoWidget no video

I am doing a project on Qt 5.2 with a video showing. I had a display problem without a movie, but the sound still works well. Please help me fix this. thanks in advance

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QMediaPlayer>
#include <QVideoWidget>
#include <QUrl>
#include <QMediaPlaylist>
#include <QWidget>
#include <QMediaObject>
#include <QtMultimedia>

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    QWidget* widget = new QWidget();

    player = new QMediaPlayer;
    QMediaPlaylist* m_playlist = new QMediaPlaylist(player);
    player->setMedia(QUrl::fromLocalFile("/storage/emulated/0/Bluetooth/video1.mp4"));

    m_widgetVideo = new QVideoWidget(widget);
    player->setVideoOutput(m_widgetVideo);

    setCentralWidget(widget);
    widget->show();
    m_playlist->setCurrentIndex(0);
    player->play();
}

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