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How to get camera supported resolutions using Qt5?

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  • T Offline
    T Offline
    tr3w
    wrote on last edited by
    #12

    Surprisingly I couldn't find a bug report about this (for linux)...
    Now here it is:
    https://bugreports.qt-project.org/browse/QTBUG-40545

    Follow, upvote, comment. Make some noise!

    (There is a bug report for windows, but there it is just not supported...
    https://bugreports.qt-project.org/browse/QTBUG-32743 )

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    • X Offline
      X Offline
      xtingray
      wrote on last edited by
      #13

      Thanks for the hint... I already voted for it! :)


      Qt Developer

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      • yeckelY Offline
        yeckelY Offline
        yeckel
        wrote on last edited by
        #14

        It looks like that gstreamer on Linux is not returing any value in: camerabinsession.cpp

        @ GstCaps *supportedCaps = 0;
        g_object_get(G_OBJECT(m_camerabin),
        (mode == QCamera::CaptureStillImage) ?
        SUPPORTED_IMAGE_CAPTURE_CAPS_PROPERTY : SUPPORTED_VIDEO_CAPTURE_CAPS_PROPERTY,
        &supportedCaps, NULL);
        if (!supportedCaps)
        return res;@

        I was trying calling gstreamer out of QT and was getting NULL as well. Is it a bug in GStreamer?

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        • yeckelY Offline
          yeckelY Offline
          yeckel
          wrote on last edited by
          #15

          It looks like that gstreamer on Linux is not returing any value in: camerabinsession.cpp

          @ GstCaps *supportedCaps = 0;
          g_object_get(G_OBJECT(m_camerabin),
          (mode == QCamera::CaptureStillImage) ?
          SUPPORTED_IMAGE_CAPTURE_CAPS_PROPERTY : SUPPORTED_VIDEO_CAPTURE_CAPS_PROPERTY,
          &supportedCaps, NULL);
          if (!supportedCaps)
          return res;@

          I was trying calling gstreamer out of QT and was getting NULL as well. Is it a bug in GStreamer?

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          0
          • SGaistS Offline
            SGaistS Offline
            SGaist
            Lifetime Qt Champion
            wrote on last edited by
            #16

            Hi,

            Either that or the device doesn't return the information. Do you have any other way to retrieve that information on your system ?

            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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            • SGaistS Offline
              SGaistS Offline
              SGaist
              Lifetime Qt Champion
              wrote on last edited by
              #17

              Hi,

              Either that or the device doesn't return the information. Do you have any other way to retrieve that information on your system ?

              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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              • yeckelY Offline
                yeckelY Offline
                yeckel
                wrote on last edited by
                #18

                Well, v4l2 is returning:

                @$ v4l2-ctl --list-formats-ext
                ioctl: VIDIOC_ENUM_FMT
                Index : 0
                Type : Video Capture
                Pixel Format: 'YUYV'
                Name : YUV 4:2:2 (YUYV)
                Size: Discrete 640x480
                Interval: Discrete 0.033s (30.000 fps)
                Interval: Discrete 0.067s (15.000 fps)
                Size: Discrete 640x360
                Interval: Discrete 0.033s (30.000 fps)
                Interval: Discrete 0.067s (15.000 fps)
                ...@

                The structure GstCaps *supportedCaps from previous code, has 0 length, but it's valid but @gst_caps_is_any(supportedCaps) == true@

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                • yeckelY Offline
                  yeckelY Offline
                  yeckel
                  wrote on last edited by
                  #19

                  Well, v4l2 is returning:

                  @$ v4l2-ctl --list-formats-ext
                  ioctl: VIDIOC_ENUM_FMT
                  Index : 0
                  Type : Video Capture
                  Pixel Format: 'YUYV'
                  Name : YUV 4:2:2 (YUYV)
                  Size: Discrete 640x480
                  Interval: Discrete 0.033s (30.000 fps)
                  Interval: Discrete 0.067s (15.000 fps)
                  Size: Discrete 640x360
                  Interval: Discrete 0.033s (30.000 fps)
                  Interval: Discrete 0.067s (15.000 fps)
                  ...@

                  The structure GstCaps *supportedCaps from previous code, has 0 length, but it's valid but @gst_caps_is_any(supportedCaps) == true@

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                  • yeckelY Offline
                    yeckelY Offline
                    yeckel
                    wrote on last edited by
                    #20

                    I've digged deeper into GStreamer plugin gstcamerabin2.c, here it's querying for pad capabilities @pad = gst_element_get_static_pad (element, padname);

                    caps = gst_pad_query_caps (pad, NULL);@ and then the query failing "GstPAd.html":http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstPad.html

                    ...gst_pad_query_caps returns all possible caps a pad can operate with, using the pad's CAPS query function, If the query fails, this function will return filter , if not NULL, otherwise ANY.

                    And this ANY is what's returned into QT and then returned as empty QList. I thing we should use another gstreamer input element aka v4l2src which is stable. Camerabin2 is marked as unstable and under development.

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                    • yeckelY Offline
                      yeckelY Offline
                      yeckel
                      wrote on last edited by
                      #21

                      I've digged deeper into GStreamer plugin gstcamerabin2.c, here it's querying for pad capabilities @pad = gst_element_get_static_pad (element, padname);

                      caps = gst_pad_query_caps (pad, NULL);@ and then the query failing "GstPAd.html":http://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstPad.html

                      ...gst_pad_query_caps returns all possible caps a pad can operate with, using the pad's CAPS query function, If the query fails, this function will return filter , if not NULL, otherwise ANY.

                      And this ANY is what's returned into QT and then returned as empty QList. I thing we should use another gstreamer input element aka v4l2src which is stable. Camerabin2 is marked as unstable and under development.

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

                        Thanks for sharing your findings !

                        Do you have that with gstreamer0.1 ? Did you check gstreamer 1 ?

                        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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                        • SGaistS Offline
                          SGaistS Offline
                          SGaist
                          Lifetime Qt Champion
                          wrote on last edited by
                          #23

                          Thanks for sharing your findings !

                          Do you have that with gstreamer0.1 ? Did you check gstreamer 1 ?

                          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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