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  4. Video on StreamingVideoSurface is inverted, or not depending on whose PC runs it

Video on StreamingVideoSurface is inverted, or not depending on whose PC runs it

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  • SGaistS Offline
    SGaistS Offline
    SGaist
    Lifetime Qt Champion
    wrote on last edited by
    #6

    Can you explain what you mean by reversed ?

    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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    • F Offline
      F Offline
      flyfisher1952
      wrote on last edited by
      #7

      The image is upside down and backwards. In the following picture I am looking to my right while the image shows me looking left as well as being upside down. Guess I should have included the picture in the original post so it would be clear.

      !https://www.dropbox.com/s/gzhee50debor2le/Capture.PNG(Me looking right, but upside down and reversed in the captured image.)!

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      • SGaistS Offline
        SGaistS Offline
        SGaist
        Lifetime Qt Champion
        wrote on last edited by
        #8

        Sorry, but I can't see the image you posted

        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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        • F Offline
          F Offline
          flyfisher1952
          wrote on last edited by
          #9

          I tried to insert it as an image, here is the link.

          https://www.dropbox.com/s/gzhee50debor2le/Capture.PNG

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          • SGaistS Offline
            SGaistS Offline
            SGaist
            Lifetime Qt Champion
            wrote on last edited by
            #10

            Ok, so flipped horizontally and vertically. Just to be sure we're on the same base: you (or one of your colleagues) are getting this "doubly flipped" image on OS X even with the embedded iSight camera ? Correct ?

            Can you add which version of Qt you are using and which version of OS X ?

            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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            • F Offline
              F Offline
              flyfisher1952
              wrote on last edited by
              #11

              I am on Windows 8.1 (all updates applied) and using Qt 5.3. My colleague sees the image unflipped in both directions but the video going to the remove server is flipped h & v.

              I've sent my partner the link to this thread so he can put in his 2 cents :)

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              • R Offline
                R Offline
                realrunner
                wrote on last edited by
                #12

                I'm the colleague.

                Here's the situation.

                Running the untainted "QML Camera Example" or the "Camera Example" my colleague's preview in the viewfinder is flipped both horizontally and vertically. His specs, as stated above are Windows 8.1 with a Logitech C920 USB web cam.

                If I run the same examples my image is just fine. I've tried with the following setups: OS X Mavericks w/ Face Time built in camera, OS X with Logitech C920, Windows 7 (in parallels) with both cameras and Windows 7 (direct, no vm) with both cameras. I've also created a build and distributed it to two other developers in our company running windows and their images are fine.

                We're all running the latest stable Qt (5.3). I've dug through the code and examples and am unable to find any difference between our two setups.

                Unfortunately the DirectShow plugin is pretty weak when it comes to webcam capture. There is no control over resolution, zoom, anything really, just preview and snapshot.

                I'm going to start digging into the DirectShow plugin directly this week to try and figure out what's going on and perhaps, along the way, expose some of its missing functionality.

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                • SGaistS Offline
                  SGaistS Offline
                  SGaist
                  Lifetime Qt Champion
                  wrote on last edited by
                  #13

                  Hi and welcome to devnet !

                  Then I wonder if there's a difference in the webcam drivers for 8.1 and 7. I don't remember if the WMF plugin has better support for webcam but it might be worth a try.

                  In the case you implement these missing functionalities and would like to submit them to the Qt project, you should directly start with the dev branch of QtMultimedia. Well you should take a look there anyway, IIRC, there's some work currently done on the DirectShow plugin.

                  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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                  • R Offline
                    R Offline
                    realrunner
                    wrote on last edited by
                    #14

                    Looking at the WMF code it looks like it has no support for webcam capture. I'll try digging into the DirectShow code. If there is a difference, hopefully something is exposed there.

                    Thanks.

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                    • D Offline
                      D Offline
                      davecotter
                      wrote on last edited by
                      #15

                      this worked for me:
                      format.setScanLineDirection(QVideoSurfaceFormat::BottomToTop);

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