问[Windows，Qt5，QMediaPlayer，QMediaPlaylist]：当当前视频源改变时，微小的持续时间黑色屏幕

EN

int main(int argc, char *argv[]) {
    QApplication a(argc, argv);

    QMediaPlaylist* playlist = new QMediaPlaylist(&a);
    playlist->addMedia(QUrl::fromLocalFile("./Resources/fractal-files/A-060405V4651.WMV"));
    playlist->addMedia(QUrl::fromLocalFile("./Resources/fractal-files/E-102604.WMV"));
    playlist->addMedia(QUrl::fromLocalFile("./Resources/fractal-files/C-102304.WMV"));

    QMediaPlayer* player = new QMediaPlayer(&a);
    player->setPlaylist(playlist);

    QVideoWidget* videoWidget = new QVideoWidget;
    player->setVideoOutput(videoWidget);

    player->play();
    videoWidget->show();

    QTimer* t = new QTimer;
    QObject::connect(t, &QTimer::timeout, [&](){
        playlist->setCurrentIndex(playlist->nextIndex());
        player->play();
        videoWidget->setWindowTitle(playlist->currentMedia().canonicalUrl().fileName());
        t->start((qrand()%5 + 5)*1000);
    });
    t->start((qrand()%5 + 5)*1000);

    QTimer* t2 = new QTimer;
    QObject::connect(t2, &QTimer::timeout, [&](){
        player->setPosition(qrand() % player->duration());
        videoWidget->setWindowTitle(playlist->currentMedia().canonicalUrl().fileName());
        t2->start((qrand()%2 + 2)*1000);
    });
    t2->start((qrand()%2 + 2)*1000);

    return a.exec();
}

player->setPosition(qrand() % player->duration());

playlist->setCurrentIndex(playlist->nextIndex());
player->play();

player->setPosition(qrand() % player->duration());