Skip to content
  • Categories
  • Recent
  • Tags
  • Popular
  • Users
  • Groups
  • Search
  • Get Qt Extensions
  • Unsolved
Collapse
Brand Logo
  1. Home
  2. Qt Development
  3. General and Desktop
  4. QCamera has strange blue tint
Forum Updated to NodeBB v4.3 + New Features

QCamera has strange blue tint

Scheduled Pinned Locked Moved Unsolved General and Desktop
qcamera
25 Posts 8 Posters 5.5k Views 2 Watching
  • Oldest to Newest
  • Newest to Oldest
  • Most Votes
Reply
  • Reply as topic
Log in to reply
This topic has been deleted. Only users with topic management privileges can see it.
  • mranger90M Offline
    mranger90M Offline
    mranger90
    wrote on last edited by
    #14

    Ok, that's pretty much what I expected. The output from the camera is probably RGB but a lot of windows drivers are expecting BGR. Or it's possible (but less likely) that your camera is putting out BGR and the driver expects RGB. You might be able to change this by examining the QImageEncoderSettings to see if there is a pixel format and changing it. Or you can try intercepting the buffers and building a QImage based on the correct orientation.

    SolaVitaeS 1 Reply Last reply
    1
    • mranger90M mranger90

      Ok, that's pretty much what I expected. The output from the camera is probably RGB but a lot of windows drivers are expecting BGR. Or it's possible (but less likely) that your camera is putting out BGR and the driver expects RGB. You might be able to change this by examining the QImageEncoderSettings to see if there is a pixel format and changing it. Or you can try intercepting the buffers and building a QImage based on the correct orientation.

      SolaVitaeS Offline
      SolaVitaeS Offline
      SolaVitae
      wrote on last edited by
      #15

      @mranger90

      Is there an easy way to do this? seems odd that it only occurs in QT, with both my actual webcam and a virtual one, but doesn't occur in an example using QML

      1 Reply Last reply
      0
      • mranger90M Offline
        mranger90M Offline
        mranger90
        wrote on last edited by mranger90
        #16

        You can check to see what the camera is supporting with

            QList<QVideoFrame::PixelFormat> formats = m_camera->supportedViewfinderPixelFormats();
            qDebug() << "supported formats " << formats;
        

        Then you might be able to do something like:

        viewFinderSettings.setPixelFormat(QVideoFrame::Format_RGB24);
        

        You might also want to check with some other application. As I recall, on windows the QCamera stuff is a rather thin layer over DirectShow so you might want to play with that to get a clear idea of whats coming off the camera.
        If worse comes to worst you may want to use something like OpenCV which will give you more control over the capture buffers and how to format them.

        SolaVitaeS 1 Reply Last reply
        1
        • mranger90M mranger90

          You can check to see what the camera is supporting with

              QList<QVideoFrame::PixelFormat> formats = m_camera->supportedViewfinderPixelFormats();
              qDebug() << "supported formats " << formats;
          

          Then you might be able to do something like:

          viewFinderSettings.setPixelFormat(QVideoFrame::Format_RGB24);
          

          You might also want to check with some other application. As I recall, on windows the QCamera stuff is a rather thin layer over DirectShow so you might want to play with that to get a clear idea of whats coming off the camera.
          If worse comes to worst you may want to use something like OpenCV which will give you more control over the capture buffers and how to format them.

          SolaVitaeS Offline
          SolaVitaeS Offline
          SolaVitae
          wrote on last edited by
          #17

          @mranger90

          The list returns (Format_RGB24, Format_YUV420P), its default set to the RGB24, and changing it to YUV420p does nothing.

          As for testing it elsewhere, it works flawlessly everywhere else. The default camera app on windows works, a webcam testing website works, skype works.

          1 Reply Last reply
          0
          • fcarneyF Offline
            fcarneyF Offline
            fcarney
            wrote on last edited by
            #18

            @SolaVitae,
            Just a shot in the dark. Have you tried explicitly setting the pixel format to QVideoFrame::Format_RGB24? Just in case some other app changed its mode?

            C++ is a perfectly valid school of magic.

            SolaVitaeS 1 Reply Last reply
            0
            • fcarneyF fcarney

              @SolaVitae,
              Just a shot in the dark. Have you tried explicitly setting the pixel format to QVideoFrame::Format_RGB24? Just in case some other app changed its mode?

              SolaVitaeS Offline
              SolaVitaeS Offline
              SolaVitae
              wrote on last edited by SolaVitae
              #19

              @fcarney
              yes, it does not change anything

              The issue does not occur on my laptop, or a friend's PC. So im guessing it has something to do with my pc. What it is I can't figure out, but I guess it's not that big of a deal if it's only on my PC. It will subconciously bother me to no ender, but oh well

              1 Reply Last reply
              0
              • SGaistS Offline
                SGaistS Offline
                SGaist
                Lifetime Qt Champion
                wrote on last edited by
                #20

                Hi,

                Since you are talking about a virtual camera, it might be generating BGR images. And since it's virtual you might be able to configure that.

                In any case, you can use QImage::rgbSwapped to convert to the right order.

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

                1 Reply Last reply
                2
                • V Offline
                  V Offline
                  VietTran
                  wrote on last edited by
                  #21

                  have you got solution for this problem?

                  1 Reply Last reply
                  0
                  • D Offline
                    D Offline
                    Dan_Dew
                    wrote on last edited by Dan_Dew
                    #22

                    Same here. Maybe after Windows-Update (Win10).
                    Viewfinder and Image of QCamera in blue.
                    People look like smurfs.
                    Different webcams, same result.
                    QML-Camera is OK. Any other Cam-Apps in Windows (Skype,..) are OK.
                    I hope of a solution, most of my apps base on that.

                    Someone with more information? Thank You.

                    1 Reply Last reply
                    0
                    • SGaistS Offline
                      SGaistS Offline
                      SGaist
                      Lifetime Qt Champion
                      wrote on last edited by
                      #23

                      Hi,

                      From the description you are giving, there might be something like a switch from RGB to BGR.

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

                      1 Reply Last reply
                      0
                      • D Offline
                        D Offline
                        Dan_Dew
                        wrote on last edited by
                        #24

                        SGaist, thank you and yes, its a BGR/RGB problem. It seems to occur rare at this time.
                        When customers complains, I would improvise with a manual switch for swapping colors at the QImages.
                        Do you have an idea for doing that at the viewfinder?

                        1 Reply Last reply
                        0
                        • SGaistS Offline
                          SGaistS Offline
                          SGaist
                          Lifetime Qt Champion
                          wrote on last edited by
                          #25

                          I don't think there's an easy way to do that except by going lower level.

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

                          1 Reply Last reply
                          0

                          • Login

                          • Login or register to search.
                          • First post
                            Last post
                          0
                          • Categories
                          • Recent
                          • Tags
                          • Popular
                          • Users
                          • Groups
                          • Search
                          • Get Qt Extensions
                          • Unsolved