GStreamer-CRITICAL Error with QCamera

[Simof]

Dear All,

I tried to run a simple project with QCamera and QMultimedia but my Camera isn't recognized correctly from GStreamer.

This is my code:

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::MainWindow)
{
    ui->setupUi(this);

    QCamera* camera;

    const QList<QCameraInfo> cameras = QCameraInfo::availableCameras();
    for (const QCameraInfo &cameraInfo : cameras)
    {
        qDebug() << cameraInfo.deviceName();
        if (cameraInfo.deviceName() == "/dev/video0")
            camera = new QCamera(cameraInfo);
    }

    qDebug() << camera;

    camera->start();
}

This is the output:

"/dev/video0"
QCamera(0x564b000daee0)
Starting camera without viewfinder available

(testCamera:4537): GStreamer-CRITICAL **: 12:43:01.419: gst_pad_get_current_caps: assertion 'GST_IS_PAD (pad)' failed

(testCamera:4537): GLib-GObject-CRITICAL **: 12:43:01.419: g_object_set: assertion 'G_IS_OBJECT (object)' failed

(testCamera:4537): GLib-GObject-CRITICAL **: 12:43:01.419: g_object_set: assertion 'G_IS_OBJECT (object)' failed
CameraBin error: "GStreamer error: negotiation problem."
Unable to query the parameter info: QCameraImageProcessingControl::WhiteBalancePreset : "Invalid argument"
Unable to query the parameter info: QCameraImageProcessingControl::ColorTemperature : "Invalid argument"
Unable to query the parameter info: QCameraImageProcessingControl::SharpeningAdjustment : "Invalid argument"
CameraBin error: "Internal data stream error."

Ubuntu 20.04 - Qt 5.12

[SGaist]

Hi and welcome to devnet,

Can you access that camera properly from GStreamer on the command line ?

[Simof]

No I've not find the right setting of GStreamer for my camera, the connection made Error after a few second.

 gst-launch-1.0 v4l2src ! jpegdec ! xvimagesink

This i s the command I tried.

[SGaist]

Then are you sure your camera is working properly ?
Which kernel version are you using ?
Did you check if you have any message related to the camera in your logs ?

[Simof]

The camera works fine with Guvcview but not working on Cheese.

My environment is Ubuntu 20.04 LTS on VirtualMachine, kernel version 5.8.0-55-generic

[SGaist]

Can you test the pipeline suggested in this stack overflow answer ?

[Simof]

Yes, I've already tested

gst-launch-1.0 v4l2src device=/dev/video0 ! image/jpeg,width=640,height=480 ! decodebin ! ximagesink

Setting pipeline to PAUSED ...
Pipeline is live and does not need PREROLL ...
Setting pipeline to PLAYING ...
New clock: GstSystemClock
ERROR: from element /GstPipeline:pipeline0/GstV4l2Src:v4l2src0: Internal data stream error.
Additional debug info:
gstbasesrc.c(3072): gst_base_src_loop (): /GstPipeline:pipeline0/GstV4l2Src:v4l2src0:
streaming stopped, reason not-negotiated (-4)
Execution ended after 0:00:00.417171499
Setting pipeline to PAUSED ...
Setting pipeline to READY ...
Setting pipeline to NULL ...
Freeing pipeline ...

[SGaist]

I wonder if it's a configuration issue. The default might be requesting something wrong.

Can you for example force the image size to ensure it's something your camera supports ?

[Simof]

@SGaist

in what way?
This is the driver configuration

[SGaist]

Sorry ! The code rendering made me miss that you configured the width/height of the image.

One thing that looks wrong is the FPS that cannot be determined. I wonder if the issue lies there.