How to read video from QCamera frame by frame ?

[onurcevik]

For a real-time image processing project I need to get frame from QCamera and stream it with UDP protocol in bmp format. But I couldn't read frame from QCamera. I can capture pictures but when I try to save it into a buffer during debugging when I view buffer its empty. Can you show me how can I save video frame in a buffer in realtime and send it ? Or atleast the saving the buffer part ? I'm really amateur using QCamera so I am posting all of my code:

udpcamera.h

#ifndef UDPCAMERA_H
#define UDPCAMERA_H

#include <QCamera>
#include <QCameraImageCapture>
#include <QMediaRecorder>
#include <QScopedPointer>
#include <QObject>

#include <QMainWindow>

namespace Ui {
class UDPCamera;
}

class QCamera;
class QCameraViewfinder;
class QCameraImageCapture;
class QVBoxLayout;
class QMenu;
class QAction;


class UDPCamera : public QMainWindow
{
    Q_OBJECT

public:
    explicit UDPCamera(QWidget *parent = nullptr);
    ~UDPCamera();
private slots:


private:

    //scoped pointer kullanabilirsin ornek: QScopedPointer<QCamera> mCamera;
    Ui::UDPCamera *ui;
    QCamera *mCamera;
    QCameraViewfinder *mCameraViewFinder;
    QCameraImageCapture *mCameraImageCapture;
    QVBoxLayout * mLayout;
    QMenu *mOptionsMenu;
    QAction *mOpenAction;
    QAction *mCloseAction;
    QAction *mCaptureAction;
    QMediaRecorder * m_mediaRecorder;

};

#endif // UDPCAMERA_H

udpcamera.cpp

#include "udpcamera.h"
#include "ui_udpcamera.h"
#include <QCamera>
#include <QCameraViewfinder>
#include <QCameraImageCapture>
#include <QVBoxLayout>
#include <QMenu>
#include <QAction>


#include <QBuffer>
#include <QObject>

UDPCamera::UDPCamera(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::UDPCamera)
{
    ui->setupUi(this);
       mCamera = new QCamera(this);
       mCameraViewFinder = new QCameraViewfinder(this);
       mCameraImageCapture = new QCameraImageCapture(mCamera,this);
       mLayout = new QVBoxLayout;
       mOptionsMenu = new QMenu("Options",this);
       mOpenAction = new QAction("Open",this);
       mCloseAction = new QAction("Close",this);
       mCaptureAction = new QAction("Capture",this);


       mOptionsMenu->addActions({mOpenAction,mCloseAction,
                               mCaptureAction});
       ui->optionsPushButton->setMenu(mOptionsMenu);

       mCamera->setViewfinder(mCameraViewFinder);
       mLayout->addWidget(mCameraViewFinder);
       ui->scrollArea->setLayout(mLayout);

       mCamera->setCaptureMode(QCamera::CaptureStillImage);
       mCameraViewFinder->show();
       mCameraImageCapture->setCaptureDestination(QCameraImageCapture::CaptureToBuffer);


       connect(mOpenAction, &QAction::triggered, [&](){
           mCamera->start();
       });

       connect(mCloseAction, &QAction::triggered, [&](){
           mCamera->stop();
       });

       connect(mCaptureAction, &QAction::triggered, [&](){
           mCameraImageCapture->capture();
       });


       connect(mCameraImageCapture, &QCameraImageCapture::imageCaptured, [=] (int id, QImage img) {
           QByteArray buf;
           QBuffer buffer(&buf);
           buffer.open(QIODevice::WriteOnly);
           img.save(&buffer, "BMP");

       });
       connect(mCameraImageCapture, &QCameraImageCapture::readyForCaptureChanged, [=] (bool state) {
           if(state == true) {
                  mCamera->searchAndLock();
                  mCameraImageCapture->capture();
                  mCamera->unlock();
              }
       });



}

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

udpcamera.ui

<?xml version="1.0" encoding="UTF-8"?>
<ui version="4.0">
 <class>UDPCamera</class>
 <widget class="QMainWindow" name="UDPCamera">
  <property name="geometry">
   <rect>
    <x>0</x>
    <y>0</y>
    <width>514</width>
    <height>395</height>
   </rect>
  </property>
  <property name="windowTitle">
   <string>UDPCamera</string>
  </property>
  <widget class="QWidget" name="centralWidget">
   <widget class="QWidget" name="layoutWidget">
    <property name="geometry">
     <rect>
      <x>40</x>
      <y>10</y>
      <width>451</width>
      <height>321</height>
     </rect>
    </property>
    <layout class="QVBoxLayout" name="verticalLayout">
     <item>
      <widget class="QPushButton" name="optionsPushButton">
       <property name="text">
        <string>Options</string>
       </property>
      </widget>
     </item>
     <item>
      <widget class="QScrollArea" name="scrollArea">
       <property name="widgetResizable">
        <bool>true</bool>
       </property>
       <widget class="QWidget" name="scrollAreaWidgetContents">
        <property name="geometry">
         <rect>
          <x>0</x>
          <y>0</y>
          <width>447</width>
          <height>286</height>
         </rect>
        </property>
       </widget>
      </widget>
     </item>
    </layout>
   </widget>
  </widget>
  <widget class="QMenuBar" name="menuBar">
   <property name="geometry">
    <rect>
     <x>0</x>
     <y>0</y>
     <width>514</width>
     <height>22</height>
    </rect>
   </property>
  </widget>
  <widget class="QToolBar" name="mainToolBar">
   <attribute name="toolBarArea">
    <enum>TopToolBarArea</enum>
   </attribute>
   <attribute name="toolBarBreak">
    <bool>false</bool>
   </attribute>
  </widget>
  <widget class="QStatusBar" name="statusBar"/>
 </widget>
 <layoutdefault spacing="6" margin="11"/>
 <resources/>
 <connections/>
</ui>

[SGaist]

Hi,

What kind of camera is it ?
What do you want to do with each frame ?