Qt+OpenCV打开视频文件并在窗口界面上显示

1、新建一个Qt Widgets Application，工程配置文件（.pro文件）内容如下：

#-------------------------------------------------
#
# Project created by QtCreator 2021-03-19T09:06:07
#
#-------------------------------------------------QT       += core guigreaterThan(QT_MAJOR_VERSION, 4): QT += widgetsTARGET = untitled2
TEMPLATE = app# The following define makes your compiler emit warnings if you use
# any feature of Qt which as been marked as deprecated (the exact warnings
# depend on your compiler). Please consult the documentation of the
# deprecated API in order to know how to port your code away from it.
DEFINES += QT_DEPRECATED_WARNINGS# You can also make your code fail to compile if you use deprecated APIs.
# In order to do so, uncomment the following line.
# You can also select to disable deprecated APIs only up to a certain version of Qt.
#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs deprecated before Qt 6.0.0SOURCES += main.cpp\mainwindow.cpp
HEADERS  += mainwindow.hFORMS    += mainwindow.ui
#工程文件 头文件和库包含进来
INCLUDEPATH += D:/QTproject/opencv_3.4.2_Qt/opencv_3.4.2_Qt/includeLIBS +=D:/QTproject/opencv_3.4.2_Qt/opencv_3.4.2_Qt/x86/bin/libopencv_*.dll

2、main.cpp内容如下：

#include "mainwindow.h"
#include <QApplication>int main(int argc, char *argv[])
{QApplication a(argc, argv);MainWindow w;w.show();return a.exec();
}

3、mainwiodow.h内容如下

#ifndef MAINWINDOW_H
#define MAINWINDOW_H#include <QMainWindow>
#include <QPushButton>
#include <qmessagebox.h>
#include <qfiledialog.h>
#include <opencv2/opencv.hpp>
#include <QDebug>
#include <QApplication>
#include <QTimer>
using namespace cv;namespace Ui {
class MainWindow;
}class MainWindow : public QMainWindow
{Q_OBJECTpublic:explicit MainWindow(QWidget *parent = 0);~MainWindow();//初始化消息框initConnect();VideoCapture cap;//消息框函数void on_btnOpen_file();void ReadFrame();QString path;QTimer * timer;private:Ui::MainWindow *ui;
};#endif // MAINWINDOW_H

4、mainwindow.cpp内容如下

#include "mainwindow.h"
#include "ui_mainwindow.h"MainWindow::MainWindow(QWidget *parent) :QMainWindow(parent),ui(new Ui::MainWindow)
{ui->setupUi(this);timer=new QTimer(this);initConnect();cap = VideoCapture();
//    Mat img=imread("1.jpg");//    imshow("cv",img);//    cvtColor(img,img,CV_BGR2GRAY);
//    imshow("cv1",img);//    Mat img_threshold;
//    threshold(img,img_threshold,150.0,255.0,THRESH_BINARY);
//    imshow("cv2",img_threshold);
//    Mat img_erode;//存放腐蚀的图片
//    //腐蚀
//    Mat elem=getStructuringElement(MORPH_RECT,Size(4,4));
//    erode(img_threshold,img_erode,elem);
//     imshow("cv3",img_erode);//     //降噪
//     medianBlur(img_erode,img_erode,);
//     //膨胀
//     Mat img_dilate;
//     Mat elem2=getStructuringElement(MORPH_RECT,Size(9,9));
//     dilate(img_erode,img_dilate,elem2);
//     imshow("cv4",img_dilate);
//    waitKey();}MainWindow::~MainWindow()
{delete ui;
}MainWindow::initConnect()
{connect(this->ui->pushButton,&QPushButton::clicked,this,&on_btnOpen_file);connect(timer,&QTimer::timeout,this,&ReadFrame);}void MainWindow::on_btnOpen_file()
{path=QFileDialog::getOpenFileName(this,"打开文件","./","*.*");this->ui->lineEdit->setText(path);//读取视频bool ret=cap.open(path.toStdString().c_str());timer->start(50);//cap=VideoCapture(0);//     Mat img=imread(path.toStdString());//     //imshow("img",img);
//     QImage im(img.data,img.cols,img.rows,QImage::Format_RGB888);
//     this->ui->label_image_before->setPixmap(QPixmap::fromImage(im));//     //模糊后
//     blur(img,frame,Size(10,10));
//     QImage im1(frame.data,frame.cols,frame.rows,QImage::Format_RGB888);
//     this->ui->label_image_after->setPixmap(QPixmap::fromImage(im1));}void MainWindow::ReadFrame()
{Mat frame;Mat frame1;Mat frame2;//opencv读取图片//qDebug()<<path;if(cap.isOpened()){//qDebug()<<ret;cap.read(frame);if(!frame.empty()){cvtColor(frame,frame1,CV_BGR2RGB);cvtColor(frame,frame2,CV_BGR2GRAY);QImage im(frame1.data,frame1.cols,frame1.rows,QImage::Format_RGB888);QImage im1(frame2.data,frame2.cols,frame2.rows,QImage::Format_Grayscale8);//imshow("cv",frame1);qDebug()<<frame.data;this->ui->label_image_before->setPixmap(QPixmap::fromImage(im));this->ui->label_image_after->setPixmap(QPixmap::fromImage(im1));//waitKey(1000);qApp->processEvents();}}}