qt 播放视频没有图像

    QMediaPlaylist * playlist;
    QMediaPlayer * player;
    QVideoWidget * videoWidget;

   playlist = new QMediaPlaylist;
    player = new QMediaPlayer;
    videoWidget = new QVideoWidget;

    setCentralWidget(videoWidget);
    //"D:/Users/Qt_project/Video_Try/3.avi
    playlist->addMedia(QUrl::fromLocalFile("C:/Users/tclxa/Desktop/fire.mp4"));
    playlist->setCurrentIndex(0);
    player->setPlaylist(playlist);
    player->setVideoOutput(videoWidget);

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

出现 下面error

DirectShowPlayerService::doRender: Unresolved error code 80040266

解决方法：

电脑安装 LAV Filter

https://www.fosshub.com/LAV-Filters.html