Displaying video in QLabel - c++

Question

I am trying to display a video in QLabet in QT Creator. I am reading video using openCV. Here is my code:
mainwindow.cpp
#include "includes.h"
#include "vidreadthread.h"
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);
VidReadThread *thread1 = new VidReadThread("Video read thread");
thread1->start();
}
MainWindow::~MainWindow()
{
delete ui;
}
vidreadthread.cpp
#include "vidreadthread.h"
#include "includes.h"
using namespace cv;
extern MainWindow *mainPtr;
VidReadThread::VidReadThread(QString s) : name(s)
{
}
void VidReadThread::run()
{
QThread::msleep(100);
VideoCapture cap;
cap.open("helicopter_with_stickers.mp4");
while(1)
{
Mat image1;
// Capture frame-by-frame
cap >> image1;
// If the frame is empty, break immediately
if (image1.empty())
break;
QImage image2 = QImage((uchar*) image1.data, image1.cols, image1.rows, image1.step, QImage::Format_RGB888);
mainPtr->ui->label1->setPixmap(QPixmap::fromImage(image2));
}
}
I am able to display the video but I can't set frame rate. Whole 60sec of video gets over in 4-5 frames. With only OpenCV I have command on frame rate with cvWaitkey(), but here msleep() doesn't seem to be working for a similar application. Please suggest a way to do so without frame skipping. I made a vidreadthread so that GUI doesn't get hanged while video is being read.
If there is any other way by which I can display OpenCV window inside my QT UI, then please recommend that as well.

Answer 1

try moveto thread may works better
.cpp
for (int i = 0; i<Camera::getCameraCount();)
ui->comboBox->addItem(QString::number(i++)); //name camera
camera = new Camera();
camera->moveToThread(&thread);
connect(this, SIGNAL(cameraOperate(int)), camera, SLOT(Operate(int)));
connect(camera, SIGNAL(updateImage(QImage)), this, SLOT(updateImage(QImage)));
void app0::updateImage(QImage image)
{
ui->videoviewer->setPixmap(QPixmap::fromImage(image));
}
camera thread:
void Camera::Operate(int _index)
{
if (open(_index)) { qDebug() << "Camera open success!";}
else { qDebug() << "Camera open failed!"; return; }
if (capture.get(28) == -1) { cout << "get 28 -1" << "\n";emit }
while (1)
{
qApp->processEvents();
Mat matin = read(); //read mat
matnow = matin;
QImage image = Mat2QImage(matin);
emit updateImage(image);
}
}
link:https://blog.csdn.net/Sun_tian/article/details/104236327