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Help capturing an image

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  • J Offline
    J Offline
    John1123
    wrote on last edited by
    #13

    my webcam is a Logi C615 HD WebCam, and im on windows 10

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    • SGaistS Offline
      SGaistS Offline
      SGaist
      Lifetime Qt Champion
      wrote on last edited by
      #14

      Can you check again with 6.7 ?

      Interested in AI ? www.idiap.ch
      Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

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      • J Offline
        J Offline
        John1123
        wrote on last edited by
        #15

        I've checked again in 6.7 and it still doesn't work.

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        • SGaistS Offline
          SGaistS Offline
          SGaist
          Lifetime Qt Champion
          wrote on last edited by
          #16

          Ok, then can you switch the backend to use the native rather than ffmpeg ?

          Interested in AI ? www.idiap.ch
          Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

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          • J Offline
            J Offline
            John1123
            wrote on last edited by
            #17

            How would I do that?

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            • SGaistS Offline
              SGaistS Offline
              SGaist
              Lifetime Qt Champion
              wrote on last edited by
              #18

              It's described here.

              Interested in AI ? www.idiap.ch
              Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

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              • J Offline
                J Offline
                John1123
                wrote on last edited by John1123
                #19

                So I've tried it, and now isReadyForCapture doesn't change to false after capture() is called but it still doesn't capture an image

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                • SGaistS Offline
                  SGaistS Offline
                  SGaist
                  Lifetime Qt Champion
                  wrote on last edited by
                  #20

                  Can you provide a minimal compilable example that shows this behaviour ?

                  Interested in AI ? www.idiap.ch
                  Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

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                  • J Offline
                    J Offline
                    John1123
                    wrote on last edited by John1123
                    #21

                    Sorry for the late reply but I'm unable to provide a minimal example. I've been digging around though and it seems to always crash after the signal imageAvailable(int id, const QVideoFrame &frame). I don't really know why that happens. I tried to do an
                    auto image = frame.toImage();
                    but this always crashes as well. I've looked into the camera example thats proved and in there it works fine

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                    • SGaistS Offline
                      SGaistS Offline
                      SGaist
                      Lifetime Qt Champion
                      wrote on last edited by
                      #22

                      Then I would compare what is done differently in your application based on the example.

                      Interested in AI ? www.idiap.ch
                      Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

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                      • J Offline
                        J Offline
                        John1123
                        wrote on last edited by John1123
                        #23

                        Yeah I did that and mine looks like it should work. After looking some more though whenever I debug I get this error I do the frame.toImage().
                        Exception at 0x7ffa5092469e, code: 0xc0000005: read access violation at: 0x0, flags=0x0 (first chance)

                        I saw online that this happens when it tries to access an invalid address but I don't see how this happens for me. This is how I have my imageAvailable

                        void VideoCapture::imageAvailable(int id, const QVideoFrame &frame){
                        QVideoFrame frame2(frame);
                        frame2.map(QVideoFrame::ReadOnly);
                        if (frame2.isValid())
                        {
                        qDebug() << "\n" << "frame2 is valid!\n";
                        }
                        else
                        qDebug() << "\n" << "frame2 is NOT valid!\n";

                        if (frame2.isReadable())
                        {
                            qDebug() << "\n" <<  "frame2 is readable!\n";
                        }
                        else
                            qDebug() << "\n" <<  "frame2 is NOT readable!\n";
                        
                        if (frame2.isMapped())
                        {
                            qDebug() << "\n" <<  "frame2 is mapped!\n";
                        }
                        else
                            qDebug() << "\n" <<  "frame2 is NOT mapped!\n";
                        qDebug() << "\n" <<  "frame2 map mode : " << frame2.mapMode() << "\n";
                        qDebug() << "\n" <<  "frame2 plane count : " << frame2.planeCount() << "\n";
                        qDebug() << "\n" <<  "frame2 size : " << frame2.size() << "\n";
                        qDebug() << "\n" <<  "frame2 pixelFormat : " << frame2.pixelFormat() << "\n";
                        qDebug() << "\n" <<  "frame2 mappedBytes_0 : " << frame2.mappedBytes(0) << "\n";
                        qDebug() << "\n" <<  "frame2 mappedBytes_1 : " << frame2.mappedBytes(1) << "\n";
                        qDebug() << "\n" <<  "frame2 mappedBytes_2 : " << frame2.mappedBytes(2) << "\n";
                        qDebug() << "\n" <<  "frame2 handleType : " << frame2.handleType() << "\n";
                        qDebug() << "\n" <<  "frame: " << frame << "\n";
                        qDebug() << "\n" <<  "frame2: " << frame2 << "\n";
                        

                        qDebug() << "\n" << "before conversion\n";
                        frame2.toImage();
                        qDebug() << "\n" << "after conversion\n";

                        }

                        the printout says that its valid, readable, it mapped, map mode is 1, plane count is 2, size is 1980X1080, pixel format is Format_NV12, mapped bytes for 0 is 2073600, mapped bytes for 1 is 1036800, mapped bytes for 2 is 0, no handle.

                        JonBJ 1 Reply Last reply
                        0
                        • J John1123

                          Yeah I did that and mine looks like it should work. After looking some more though whenever I debug I get this error I do the frame.toImage().
                          Exception at 0x7ffa5092469e, code: 0xc0000005: read access violation at: 0x0, flags=0x0 (first chance)

                          I saw online that this happens when it tries to access an invalid address but I don't see how this happens for me. This is how I have my imageAvailable

                          void VideoCapture::imageAvailable(int id, const QVideoFrame &frame){
                          QVideoFrame frame2(frame);
                          frame2.map(QVideoFrame::ReadOnly);
                          if (frame2.isValid())
                          {
                          qDebug() << "\n" << "frame2 is valid!\n";
                          }
                          else
                          qDebug() << "\n" << "frame2 is NOT valid!\n";

                          if (frame2.isReadable())
                          {
                              qDebug() << "\n" <<  "frame2 is readable!\n";
                          }
                          else
                              qDebug() << "\n" <<  "frame2 is NOT readable!\n";
                          
                          if (frame2.isMapped())
                          {
                              qDebug() << "\n" <<  "frame2 is mapped!\n";
                          }
                          else
                              qDebug() << "\n" <<  "frame2 is NOT mapped!\n";
                          qDebug() << "\n" <<  "frame2 map mode : " << frame2.mapMode() << "\n";
                          qDebug() << "\n" <<  "frame2 plane count : " << frame2.planeCount() << "\n";
                          qDebug() << "\n" <<  "frame2 size : " << frame2.size() << "\n";
                          qDebug() << "\n" <<  "frame2 pixelFormat : " << frame2.pixelFormat() << "\n";
                          qDebug() << "\n" <<  "frame2 mappedBytes_0 : " << frame2.mappedBytes(0) << "\n";
                          qDebug() << "\n" <<  "frame2 mappedBytes_1 : " << frame2.mappedBytes(1) << "\n";
                          qDebug() << "\n" <<  "frame2 mappedBytes_2 : " << frame2.mappedBytes(2) << "\n";
                          qDebug() << "\n" <<  "frame2 handleType : " << frame2.handleType() << "\n";
                          qDebug() << "\n" <<  "frame: " << frame << "\n";
                          qDebug() << "\n" <<  "frame2: " << frame2 << "\n";
                          

                          qDebug() << "\n" << "before conversion\n";
                          frame2.toImage();
                          qDebug() << "\n" << "after conversion\n";

                          }

                          the printout says that its valid, readable, it mapped, map mode is 1, plane count is 2, size is 1980X1080, pixel format is Format_NV12, mapped bytes for 0 is 2073600, mapped bytes for 1 is 1036800, mapped bytes for 2 is 0, no handle.

                          JonBJ Offline
                          JonBJ Offline
                          JonB
                          wrote on last edited by
                          #24

                          @John1123 said in Help capturing an image:

                          Exception at 0x7ffa5092469e, code: 0xc0000005: read access violation at: 0x0, flags=0x0 (first chance)

                          This is a "first chance" exception. So far as I understand it, that is an MSVC-ism and is to be ignored as not relevant. Do you have any other problem/diagnostic other than a first chance exception?

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                          • J Offline
                            J Offline
                            John1123
                            wrote on last edited by
                            #25

                            Hi Jon, I don't have any other problem. When I build I don't get anything and when I run with the debugger on, that's the only issue that I have

                            JonBJ 1 Reply Last reply
                            0
                            • J John1123

                              Hi Jon, I don't have any other problem. When I build I don't get anything and when I run with the debugger on, that's the only issue that I have

                              JonBJ Offline
                              JonBJ Offline
                              JonB
                              wrote on last edited by
                              #26

                              @John1123 Then (assuming nothing actually goes wrong) ignore it!

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                              0
                              • J Offline
                                J Offline
                                John1123
                                wrote on last edited by
                                #27

                                That makes sense but I'm wondering if I should ignore it though, because when I run it, it crashes there

                                1 Reply Last reply
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