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Forum Update on Monday, May 27th 2025

How to use QAbstractVideoFilter to process frames from camera

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  • C Offline
    C Offline
    cs_a994
    wrote on 22 Sept 2015, 13:46 last edited by
    #18

    Hello!

    Is it possible to use the QVideoFilterRunnuble without QML?

    As an example I would like to embed it into Camera example ( http://doc.qt.io/qt-5/qtmultimediawidgets-camera-example.html ) to be able to change data format.

    Thank you.

    M 1 Reply Last reply 25 Sept 2015, 05:30
    0
    • C cs_a994
      22 Sept 2015, 13:46

      Hello!

      Is it possible to use the QVideoFilterRunnuble without QML?

      As an example I would like to embed it into Camera example ( http://doc.qt.io/qt-5/qtmultimediawidgets-camera-example.html ) to be able to change data format.

      Thank you.

      M Offline
      M Offline
      medyakovvit
      wrote on 25 Sept 2015, 05:30 last edited by
      #19

      @cs_a994 Don't think so. But you can try to subclass QAbstractVideoSurface.

      C 1 Reply Last reply 25 Sept 2015, 13:14
      0
      • M medyakovvit
        25 Sept 2015, 05:30

        @cs_a994 Don't think so. But you can try to subclass QAbstractVideoSurface.

        C Offline
        C Offline
        cs_a994
        wrote on 25 Sept 2015, 13:14 last edited by
        #20

        @medyakovvit

        Thank you. I know about this way. But use of filters seams to me more neat.

        I tryed to use filters with QML ( in the Camera example ) and did not yet get a result.

        M T 2 Replies Last reply 25 Sept 2015, 16:35
        0
        • C cs_a994
          25 Sept 2015, 13:14

          @medyakovvit

          Thank you. I know about this way. But use of filters seams to me more neat.

          I tryed to use filters with QML ( in the Camera example ) and did not yet get a result.

          M Offline
          M Offline
          medyakovvit
          wrote on 25 Sept 2015, 16:35 last edited by
          #21

          @cs_a994
          OK. I f you have a questions about qml camera and filters, I will try to help you.

          1 Reply Last reply
          0
          • C cs_a994
            25 Sept 2015, 13:14

            @medyakovvit

            Thank you. I know about this way. But use of filters seams to me more neat.

            I tryed to use filters with QML ( in the Camera example ) and did not yet get a result.

            T Offline
            T Offline
            theshadowx
            wrote on 25 Sept 2015, 22:00 last edited by
            #22

            @cs_a994

            I have put a QtQuick app in github using QAbstractVideoFilter with OpenCV.

            I hope it helps you.

            Cheers

            C 1 Reply Last reply 28 Sept 2015, 12:33
            0
            • T theshadowx
              25 Sept 2015, 22:00

              @cs_a994

              I have put a QtQuick app in github using QAbstractVideoFilter with OpenCV.

              I hope it helps you.

              Cheers

              C Offline
              C Offline
              cs_a994
              wrote on 28 Sept 2015, 12:33 last edited by
              #23

              @theshadowx

              Thank you very much. I'll study it soon. I hope it will help.

              1 Reply Last reply
              0
              • M Offline
                M Offline
                mikeitexpert
                wrote on 4 Jan 2019, 21:28 last edited by mikeitexpert 1 Apr 2019, 23:21
                #24

                @theshadowx

                I get the below error if I try the canny code from git hub. (https://github.com/theshadowx/Qt_OpenCV)

                I don't know much about mql but I know QT intermediately.

                Thank you

                01:45:55: Starting /home/mike/Downloads/Qt_OpenCV-master/QtQuick/build-CannyQml-Desktop_Qt_5_12_0_GCC_64bit-Debug/CannyQml...
                QML debugging is enabled. Only use this in a safe environment.

                (CannyQml:24471): GStreamer-CRITICAL **: 01:45:57.866: write map requested on non-writable buffer
                01:45:57: The program has unexpectedly finished.
                01:45:57: The process was ended forcefully.
                01:45:58: /home/mike/Downloads/Qt_OpenCV-master/QtQuick/build-CannyQml-Desktop_Qt_5_12_0_GCC_64bit-Debug/CannyQml crashed.

                T 1 Reply Last reply 5 Jan 2019, 08:15
                0
                • M mikeitexpert
                  4 Jan 2019, 21:28

                  @theshadowx

                  I get the below error if I try the canny code from git hub. (https://github.com/theshadowx/Qt_OpenCV)

                  I don't know much about mql but I know QT intermediately.

                  Thank you

                  01:45:55: Starting /home/mike/Downloads/Qt_OpenCV-master/QtQuick/build-CannyQml-Desktop_Qt_5_12_0_GCC_64bit-Debug/CannyQml...
                  QML debugging is enabled. Only use this in a safe environment.

                  (CannyQml:24471): GStreamer-CRITICAL **: 01:45:57.866: write map requested on non-writable buffer
                  01:45:57: The program has unexpectedly finished.
                  01:45:57: The process was ended forcefully.
                  01:45:58: /home/mike/Downloads/Qt_OpenCV-master/QtQuick/build-CannyQml-Desktop_Qt_5_12_0_GCC_64bit-Debug/CannyQml crashed.

                  T Offline
                  T Offline
                  theshadowx
                  wrote on 5 Jan 2019, 08:15 last edited by
                  #25

                  @mikeitexpert
                  Could you add this issue in https://github.com/theshadowx/Qt_OpenCV/issues

                  Thanks

                  1 Reply Last reply
                  0
                  • M Offline
                    M Offline
                    mikeitexpert
                    wrote on 5 Jan 2019, 08:32 last edited by
                    #26

                    here: https://github.com/theshadowx/Qt_OpenCV/issues/5

                    Is there any way I can convert qml to c++ code just to get an idea how your methods works in pure C++?

                    Thank you

                    1 Reply Last reply
                    0
                    • M Offline
                      M Offline
                      mikeitexpert
                      wrote on 7 Jan 2019, 08:34 last edited by
                      #27

                      Please let me know if there is any update on this.

                      Mike

                      1 Reply Last reply
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