Qt应用程序开发五：QMediaPlayer播放视频，提取视频帧，多窗口播放同一视频

本文链接：https://blog.youkuaiyun.com/xzpblog/article/details/87434952

本文详细介绍使用Qt的QMediaPlayer和QAbstractVideoSurface进行视频播放及视频帧提取的方法。通过QMediaPlayer结合QVideoWidget实现视频播放，利用QAbstractVideoSurface提取视频帧并转化为QImage，适用于QML和QLabel加载或QWidget的paintEvent绘画。文中提供了具体代码实例，包括视频播放器的创建、视频文件选择、视频帧的提取和显示。

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效果图：

方法一：QMediaPlayer+QVideoWidget （如果其他格式视频播放不出来，安装一个视频解码器可以解决)

#include "QMutPlayer.h"
#include "ui_QMutPlayer.h"
#include<QFileDialog>
#include<QDebug>

QMutPlayer::QMutPlayer(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::QMutPlayer)
{
    ui->setupUi(this);
    mVideoPlayer = new QMediaPlayer(this);
    mSurfacePlayer = new QMediaPlayer(this);
    mVideoWidget  = new QVideoWidget(ui->lab_videowidget);
    mVideoPlayer->setVideoOutput(mVideoWidget);
}

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

void QMutPlayer::on_btn_select_video_clicked()
{
    QString fileName = QFileDialog::getOpenFileName(this, tr("Open File"),"", tr("video (*.mp4 *.wav *.avi)"));
    if(fileName.isEmpty())
        return;
    mVideoPlayer->setMedia(QUrl(fileName));
    mVideoPlayer->play();

}

void QMutPlayer::showEvent(QShowEvent *event)
{
    Q_UNUSED(event)
    mVideoWidget->resize(ui->lab_videowidget->size());
}

方法二：QMediaPlayer+ QAbstractVideoSurface 提取视频帧

然后将视频帧转化为QImage,用QML 和QLabel 加载，或者QWidget 的paintEvent 绘画出来

//提取视频帧

#ifndef VIDEOSURFACE_H
#define VIDEOSURFACE_H

#include <QObject>
#include<QAbstractVideoSurface>

class VideoSurface : public QAbstractVideoSurface
{
    Q_OBJECT
public:
    explicit VideoSurface(QObject *parent = 0);
signals:

    void showImage(QImage img);

protected:
        bool present(const QVideoFrame &frame);
    QList<QVideoFrame::PixelFormat> supportedPixelFormats(QAbstractVideoBuffer::HandleType handleType = QAbstractVideoBuffer::NoHandle) const;
};

#endif // VIDEOSURFACE_H


#include "VideoSurface.h"
#include<QPixmap>
VideoSurface::VideoSurface(QObject *parent) : QAbstractVideoSurface(parent)
{

}

QList<QVideoFrame::PixelFormat> VideoSurface::supportedPixelFormats(QAbstractVideoBuffer::HandleType handleType) const
{
    Q_UNUSED(handleType);
    QList<QVideoFrame::PixelFormat> listPixelFormats;
        listPixelFormats << QVideoFrame::Format_RGB32
            << QVideoFrame::Format_BGR32;
        return listPixelFormats;

}

 bool VideoSurface::present(const QVideoFrame &frame)
 {
     if (frame.isValid())
         {
             QVideoFrame cloneFrame(frame);
             cloneFrame.map(QAbstractVideoBuffer::ReadOnly);
             QImage recvImage(cloneFrame.bits(), cloneFrame.width(), cloneFrame.height(), QVideoFrame::imageFormatFromPixelFormat(cloneFrame.pixelFormat()));
             cloneFrame.unmap();
             emit showImage(recvImage);
             return true;
         }
         return false;

 }

//调用

    mSurfacePlayer = new QMediaPlayer(this);
    mVideoSurface = new VideoSurface(this);
    mSurfacePlayer->setVideoOutput(mVideoSurface);
    connect(mVideoSurface,SIGNAL(showImage(QImage)),SLOT(onShowImage(QImage)));

/QML 刷新图片 需要用到QQuickImageProvider 


#ifndef IMAGEPROVIDER_H
#define IMAGEPROVIDER_H


#include <QQuickImageProvider>
class ImageProvider : public QQuickImageProvider
{

public:
    explicit ImageProvider();
public:
    void addImage(QImage &image);


    QPixmap requestPixmap(const QString &id, QSize *size, const QSize &requestedSize);

    QImage  requestImage(const QString &id, QSize *size, const QSize &requestedSize);

private:

    QImage mImage;

};

#endif // IMAGEPROVIDER_H


#include "ImageProvider.h"

ImageProvider::ImageProvider(): QQuickImageProvider(QQuickImageProvider::Image)
{

}

void ImageProvider::addImage(QImage &image)
{
    mImage = image;
}

QPixmap ImageProvider::requestPixmap(const QString &id, QSize *size, const QSize &requestedSize)
{
    return QPixmap::fromImage(mImage);
}

QImage ImageProvider::requestImage(const QString &id, QSize *size, const QSize &requestedSize)
{
    return mImage;
}


#ifndef SHOWIMAGE_H
#define SHOWIMAGE_H

#include <QObject>
#include"ImageProvider.h"

class ShowImage : public QObject
{
    Q_OBJECT
public:
      static ShowImage *instance();
    ~ShowImage();
      ImageProvider *m_pImgProvider;
      void setImage(QImage image);
  signals:
      void callQmlRefeshImg();
private:
      ShowImage(QObject *parent = 0);
      static ShowImage *mShowImage;
};

#endif // SHOWIMAGE_H


#include "ShowImage.h"

ShowImage* ShowImage::mShowImage = NULL;

ShowImage:: ShowImage(QObject *parent) : QObject(parent)
{
    m_pImgProvider = new ImageProvider();
}

ShowImage *ShowImage::instance()
{
    if(mShowImage == NULL)
        mShowImage = new ShowImage;
    return mShowImage;
}

ShowImage::~ShowImage()
{
    delete m_pImgProvider;
}

void ShowImage::setImage(QImage image)
{
    m_pImgProvider->addImage(image);
    emit callQmlRefeshImg();
}


#ifndef QMLLOADWIDGET_H
#define QMLLOADWIDGET_H

#include <QWidget>
#include<QQuickWidget>


class QmlLoadWidget : public QQuickWidget
{
    Q_OBJECT
public:
    explicit QmlLoadWidget(QWidget *parent = 0);
signals:
    void errMessage(QString msg);
public slots:
     void addImage(QImage image);
     void getErr(QQuickWindow::SceneGraphError error, const QString &message);

};

#endif // QMLLOADWIDGET_H


#include "QmlLoadWidget.h"
#include<QQmlEngine>
#include<QQmlContext>
#include"ShowImage.h"

QmlLoadWidget::QmlLoadWidget(QWidget *parent) : QQuickWidget(parent)
{
    this->resize(parent->size());
    setResizeMode(QQuickWidget::SizeRootObjectToView);
    rootContext()->setContextProperty("CodeImage",ShowImage::instance());
    engine()->addImageProvider("CodeImg",ShowImage::instance()->m_pImgProvider);
    setSource(QUrl("qrc:/QmlRender/LoadVideImage.qml"));


}

void QmlLoadWidget::addImage(QImage image)
{
    ShowImage::instance()->setImage(image);
}

void QmlLoadWidget::getErr(QQuickWindow::SceneGraphError error, const QString &message)
{
    emit errMessage(message);
}

完整代码下载地址：https://download.youkuaiyun.com/download/xzpblog/10960022