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QT and Video Interfaces

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  • jsulmJ jsulm

    @Stevendragoes said in QT and Video Interfaces:

    it gives me this error

    In which line exactly?

    S Offline
    S Offline
    Stevendragoes
    wrote on last edited by
    #3

    @jsulm said in QT and Video Interfaces:

    @Stevendragoes said in QT and Video Interfaces:

    it gives me this error

    In which line exactly?

    Oh the whole Program forcefully fails.. And it can't start the application. The screen compiles and build successfully but it just fails to launch the application.

    1 Reply Last reply
    0
    • mranger90M Offline
      mranger90M Offline
      mranger90
      wrote on last edited by
      #4

      Does it crash when executing inside of QtCreator or outside ?
      If it crashes inside of QtCreator than check the stack trace.
      If it crashes outside of QtCreator than you need to do a deploy.

      S 1 Reply Last reply
      2
      • mrjjM Offline
        mrjjM Offline
        mrjj
        Lifetime Qt Champion
        wrote on last edited by mrjj
        #5

        Hi
        Seems to be a dangling pointer maybe ?
        You have
        QWidget* videoframe;

        which you never set to anything in the code shown.

        You show an ui file so i wonder if you mean

        ui->videoframe
        instead ?

        To use the one you have placed on the UI and not the one you have manually added.

        S 2 Replies Last reply
        2
        • S Stevendragoes

          Hi All,

          I am developing a personal GUI project to integrate OPENCV with QT. I have successfully integrated using MinGW 7.3.0. My Current GUI looks like this.
          d01b7078-391d-48f6-a37c-5d4fcdcc3bfb-image.png

          I want to do Offline Loading Video and Online Camera Interfaces using two PushButtons.
          I followed this tutorial https://www.youtube.com/watch?v=ZoFm_Mznq1M
          I have created the FileDialog and it is working fine.
          However, I don't want to write "this" and take up the whole screen of my widget. Hence, I created a sizeable widget named "videoframe" (dotted blue rectangle)

          mainwindow.h

          class MainWindow : public QMainWindow
          {
              Q_OBJECT                                    
          
          public:
              QWidget* videoframe;
              Ui::MainWindow *ui;
              std::string path;
              MainWindow(QWidget *parent = nullptr);
              ~MainWindow();
              QString qpath;
          
              QMediaPlayer* player;
              QVideoWidget* vw;
              QProgressBar* bar;
              QSlider* slider;
          
          private slots:
              void on_actionLoad_Video_triggered();
              void closeEvent(QCloseEvent *event);
              void on_actionPlay_triggered();
              void on_actionPause_triggered();
              void on_actionStop_triggered();
          
          private:
              QString filepath;
          };
          

          mainwindow.cpp

          MainWindow::MainWindow(QWidget *parent)
              : QMainWindow(parent)
              , ui(new Ui::MainWindow)
          {
              ui->setupUi(this);
              player = new QMediaPlayer(this);
              vw = new QVideoWidget(videoframe);
              //to fix the Forcefully exited
              //to fix the Video WIdget
              //To resize and put into the videoframe
          
              player->setVideoOutput(vw);
          
          }
          void MainWindow::on_actionLoad_Video_triggered()
          {
              QMessageBox::StandardButton loadBtn = QMessageBox::question( this, "MainWindow",tr("Load Video? \n"), QMessageBox::No | QMessageBox::Yes,QMessageBox::Yes);
              if (loadBtn == QMessageBox::Yes)
              {
                  qpath = QFileDialog::getOpenFileName(this, "Load Video File"); //Input code to skip the event when cancel is pressed
                  if (qpath.isNull())
                  {
                      ui->textEdit->append("Cannot get file, user cancelled while choosing file");
                  }
                  else
                  {
                      path = qpath.toLocal8Bit().constData();
                      cShowVideo(ui, path, qpath);                        //For OPENCV analysis and filtering
                      on_actionStop_triggered();                          //Stop the Video
                      player->setMedia(QUrl::fromLocalFile(qpath));       //Set the Media
                      on_actionPlay_triggered();                          //Play the Media
                  }
              }
              else
              {
                  ui->textEdit->setText("User Cancelled");
              }
          }
          

          however, when i try to run the program,

          it gives me this error. which means that I failed to cast the video widget into the Qwidget frame? My main motive is to load the video into the QWidget named 'videoframe'.

          Any idea how to do so? Appreciate your help.

          Pl45m4P Offline
          Pl45m4P Offline
          Pl45m4
          wrote on last edited by
          #6
          This post is deleted!
          1 Reply Last reply
          0
          • mranger90M mranger90

            Does it crash when executing inside of QtCreator or outside ?
            If it crashes inside of QtCreator than check the stack trace.
            If it crashes outside of QtCreator than you need to do a deploy.

            S Offline
            S Offline
            Stevendragoes
            wrote on last edited by
            #7

            @mranger90 said in QT and Video Interfaces:

            Does it crash when executing inside of QtCreator or outside ?
            If it crashes inside of QtCreator than check the stack trace.
            If it crashes outside of QtCreator than you need to do a deploy.

            Hi @mranger90 it crashed inside the QT Creator when I try to press the run button

            1 Reply Last reply
            0
            • mrjjM mrjj

              Hi
              Seems to be a dangling pointer maybe ?
              You have
              QWidget* videoframe;

              which you never set to anything in the code shown.

              You show an ui file so i wonder if you mean

              ui->videoframe
              instead ?

              To use the one you have placed on the UI and not the one you have manually added.

              S Offline
              S Offline
              Stevendragoes
              wrote on last edited by
              #8

              @mrjj said in QT and Video Interfaces:

              Hi
              Seems to be a dangling pointer maybe ?
              You have
              QWidget* videoframe;

              which you never set to anything in the code shown.

              You show an ui file so i wonder if you mean

              ui->videoframe
              instead ?

              To use the one you have placed on the UI and not the one you have manually added.

              @mrjj yea I want to use the QVideoWidget inside the "videoframe" Qwidget that is created in the Ui shown in dotted rectangle in the UI screen shot. However I don't know how to use link it all together, is it ui->videoframe like you mentioned?

              1 Reply Last reply
              0
              • mrjjM mrjj

                Hi
                Seems to be a dangling pointer maybe ?
                You have
                QWidget* videoframe;

                which you never set to anything in the code shown.

                You show an ui file so i wonder if you mean

                ui->videoframe
                instead ?

                To use the one you have placed on the UI and not the one you have manually added.

                S Offline
                S Offline
                Stevendragoes
                wrote on last edited by
                #9

                @mrjj So should. It be

                vw = new QVideoWidget (ui->videoframe)
                Instead of

                vw= new QVideoWidget(videoframe)?

                mrjjM 1 Reply Last reply
                0
                • S Stevendragoes

                  @mrjj So should. It be

                  vw = new QVideoWidget (ui->videoframe)
                  Instead of

                  vw= new QVideoWidget(videoframe)?

                  mrjjM Offline
                  mrjjM Offline
                  mrjj
                  Lifetime Qt Champion
                  wrote on last edited by
                  #10

                  @Stevendragoes
                  Hi
                  Yes as the UI hold the widgets you put in visually and
                  the other one seems like a dangling pointer which will crash.

                  1 Reply Last reply
                  0
                  • S Offline
                    S Offline
                    Stevendragoes
                    wrote on last edited by
                    #11

                    Hello @mrjj

                    I have done the necessary changes. However, the video is not showing in the rectangle frame that I have drawn.

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                    0
                    • S Offline
                      S Offline
                      Stevendragoes
                      wrote on last edited by
                      #12

                      Hello @jsulm @mrjj

                      I have typed in according to what you have mentioned

                      MainWindow::MainWindow(QWidget *parent)
                          : QMainWindow(parent)
                          , ui(new Ui::MainWindow)
                      {
                          ui->setupUi(this);
                          player = new QMediaPlayer(ui->videowidget);
                          vw = new QVideoWidget(ui->videowidget);
                          player->setVideoOutput(vw);
                      }
                      
                      

                      However, the video does not load when I loaded the video. I have the text box to check the file path. the file path is fine. However, the video could not be displayed in the custom rectangle box that I drew.
                      e0ca49fd-8dec-4c34-9e13-a34c8d9e62ad-image.png

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                      0
                      • S Offline
                        S Offline
                        Stevendragoes
                        wrote on last edited by
                        #13

                        Hello @jsulm and @mrjj

                        After trying out and researching, I found a lazy man's way of showing in the UI, could be called my first draft.

                        MainWindow::MainWindow(QWidget *parent)
                            : QMainWindow(parent)
                            , ui(new Ui::MainWindow)
                        {
                            ui->setupUi(this);
                            player = new QMediaPlayer(this);
                            vw = new QVideoWidget(this);
                            player->setVideoOutput(vw);
                            vw->setGeometry(30,140,800,600);
                            vw->show();
                        }
                        
                        

                        However, I want to cast into the grid layout as the result wasn't up to my expectations.. I want the videoframe to resize when the window resizes.. Any Idea how? I didn't use the QWidget to load the video. If i were to use the QWidget to load the video, it will be good.

                        jsulmJ 1 Reply Last reply
                        0
                        • S Stevendragoes

                          Hello @jsulm and @mrjj

                          After trying out and researching, I found a lazy man's way of showing in the UI, could be called my first draft.

                          MainWindow::MainWindow(QWidget *parent)
                              : QMainWindow(parent)
                              , ui(new Ui::MainWindow)
                          {
                              ui->setupUi(this);
                              player = new QMediaPlayer(this);
                              vw = new QVideoWidget(this);
                              player->setVideoOutput(vw);
                              vw->setGeometry(30,140,800,600);
                              vw->show();
                          }
                          
                          

                          However, I want to cast into the grid layout as the result wasn't up to my expectations.. I want the videoframe to resize when the window resizes.. Any Idea how? I didn't use the QWidget to load the video. If i were to use the QWidget to load the video, it will be good.

                          jsulmJ Online
                          jsulmJ Online
                          jsulm
                          Lifetime Qt Champion
                          wrote on last edited by
                          #14

                          @Stevendragoes said in QT and Video Interfaces:

                          Any Idea how?

                          Well, put it into your layout.

                          https://forum.qt.io/topic/113070/qt-code-of-conduct

                          1 Reply Last reply
                          2
                          • S Offline
                            S Offline
                            Stevendragoes
                            wrote on last edited by
                            #15

                            Alright @jsulm I will go and learn about the layout and do some trial and errors. Any questions I will ask again. Thanks for assisting me

                            1 Reply Last reply
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