QT多媒体播放视频并显示字幕

亦凉 2023-01-20 09:45 241阅读 0赞

# #

标签： [\# Qt][Qt]  [qt][]  [多媒体][Link 1]  [字幕][Link 2]  [视频播放][Link 3]

![在这里插入图片描述][18d4e3168ff52e3b920be52696dfa0e7.png]

QVideoWidget *videoWidget = new QVideoWidget();
        QMediaPlayer *player = new QMediaPlayer();
        player->setMedia(QUrl::fromLocalFile("/Users/pikachu/Movies/《千与千寻》片段.mp4"));
        player->setVideoOutput(videoWidget);
        setCentralWidget(videoWidget);
        player->play();
        resize(1920, 1080);

但是 QMediaPlayer却没有办法播放字幕  
一个做法是自己把字幕画上去  
想法来源：https://forum.qt.io/topic/47378/again-how-show-a-subtitle-on-qmediaplayer  
![在这里插入图片描述][540b21a0d652e774dccf7d392d06435f.png]  
我根据这个想法，做了一个实现  
![在这里插入图片描述][bbd856b903bb557d5f35e866cbcc8bf8.png]

resize(1440, 720);
        auto videoItem = new QGraphicsVideoItem();
        auto srtTextItem = new QGraphicsTextItem();
        auto scene = new QGraphicsScene();
        auto view = new QGraphicsView(scene);
        scene->addItem(videoItem);
        scene->addItem(srtTextItem);
        srtTextItem->setPlainText("SRT TEXT");
        setCentralWidget(view);
        QMediaPlayer *player = new QMediaPlayer(this, QMediaPlayer::VideoSurface);
        player->setMedia(QUrl::fromLocalFile("/Users/pikachu/Movies/《千与千寻》片段.mp4"));
        player->setVideoOutput(videoItem);
        player->play();
        view->show();
        videoItem->setSize(size());

这样就能显示文字了，最后就是把文字显示在视频的底部中间部分  
调一下字的位置  
![在这里插入图片描述][1aac64dca30f5a5e1664a790660f2a50.png]

auto textRectSize = srtTextItem->boundingRect().size();
        auto target_y = videoItem->size().height() - textRectSize.height();
        auto target_x = (videoItem->size().width() - textRectSize.width()) / 2;
        srtTextItem->setPos(target_x, target_y);

字幕一般是白色，且比目前我的这个稍微大一点

![在这里插入图片描述][fc48c3aef6607990f59230b997f215aa.png]

srtTextItem->setDefaultTextColor(QColorConstants::White);
        auto font = srtTextItem->font();
        font.setPixelSize(26);
        srtTextItem->setFont(font);

*  1
 *  2
 *  3
 *  4
 *  5

这样就达到我的预期了。  
后面就是如何读取SRT字幕文件，并根据时间显示不同的字幕文字。  
这里就不写了，剩下的部分，在我写的一个稍微大的项目里整合了在一起。

# 附 #

所有代码

// 头文件
    #ifndef MAINWINDOW_H
    #define MAINWINDOW_H
    
    #include <QMainWindow>
    
    class MainWindow : public QMainWindow
    {
        Q_OBJECT
    
    public:
        MainWindow(QWidget *parent = nullptr);
        ~MainWindow();
    };
    #endif // MAINWINDOW_H
    
    // 源文件
    #include "mainwindow.h"
    #include <QtWidgets>
    #include <QVideoWidget>
    #include <QtMultimedia>
    #include <QGraphicsVideoItem>
    #include <QGraphicsTextItem>
    #include <QGraphicsScene>
    #include <QGraphicsView>
    #include <QDebug>
    MainWindow::MainWindow(QWidget *parent)
        : QMainWindow(parent)
    {
        resize(1440, 720);
        auto videoItem = new QGraphicsVideoItem();
        auto srtTextItem = new QGraphicsTextItem();
        auto scene = new QGraphicsScene();
        auto view = new QGraphicsView(scene);
        scene->addItem(videoItem);
        scene->addItem(srtTextItem);
        srtTextItem->setPlainText("SRT TEXT");
        setCentralWidget(view);
        QMediaPlayer *player = new QMediaPlayer(this, QMediaPlayer::VideoSurface);
        player->setMedia(QUrl::fromLocalFile("/Users/pikachu/Movies/《千与千寻》片段.mp4"));
        player->setVideoOutput(videoItem);
        player->play();
        view->show();
        videoItem->setSize(size());
        srtTextItem->setDefaultTextColor(QColorConstants::White);
        auto font = srtTextItem->font();
        font.setPixelSize(26);
        
        srtTextItem->setFont(font);
        auto textRectSize = srtTextItem->boundingRect().size();
        auto target_y = videoItem->size().height() - textRectSize.height();
        auto target_x = (videoItem->size().width() - textRectSize.width()) / 2;
        srtTextItem->setPos(target_x, target_y);
    }
    
    MainWindow::~MainWindow()
    {
    }

补充：  
如果只用纯白色的文字，在白色的背景下就看不见，所以要加一个阴影。  
代码如下

QGraphicsDropShadowEffect *e2 = new QGraphicsDropShadowEffect(this);
        e2->setOffset(1,1);
        srtTextItem->setGraphicsEffect(e2);

[Qt]: https://www.freesion.com/tag/%23+Qt/
[qt]: https://www.freesion.com/tag/qt/
[Link 1]: https://www.freesion.com/tag/%E5%A4%9A%E5%AA%92%E4%BD%93/
[Link 2]: https://www.freesion.com/tag/%E5%AD%97%E5%B9%95/
[Link 3]: https://www.freesion.com/tag/%E8%A7%86%E9%A2%91%E6%92%AD%E6%94%BE/
[18d4e3168ff52e3b920be52696dfa0e7.png]: /images/20221021/94d1bf9dcb9b40ae86131043d31aa079.png
[540b21a0d652e774dccf7d392d06435f.png]: /images/20221021/0b9d739546ac49b8839e30b199f98bf1.png
[bbd856b903bb557d5f35e866cbcc8bf8.png]: /images/20221021/8a8273dbfc214d649c8484b431ec3376.png
[1aac64dca30f5a5e1664a790660f2a50.png]: /images/20221021/0efdae89f2bb45cf8ec82adbd5ecd773.png
[fc48c3aef6607990f59230b997f215aa.png]: /images/20221021/b3654d98660b4ecd91f74039540dbcb5.png