A camera problem.

jenya7

This is my constructor

Camera::Camera(QObject *parent) : QObject(parent)
{
    //Camera devices:

    QActionGroup *videoDevicesGroup = new QActionGroup(this);
    videoDevicesGroup->setExclusive(true);
    const QList<QCameraInfo> availableCameras = QCameraInfo::availableCameras();
    for (const QCameraInfo &cameraInfo : availableCameras)
 {
        QAction *videoDeviceAction = new QAction(cameraInfo.description(), videoDevicesGroup);
        videoDeviceAction->setCheckable(true);
        videoDeviceAction->setData(QVariant::fromValue(cameraInfo));
        if (cameraInfo == QCameraInfo::defaultCamera())
            videoDeviceAction->setChecked(true);
    }

    connect(videoDevicesGroup, &QActionGroup::triggered, this, &Camera::updateCameraDevice);

    setCamera(QCameraInfo::defaultCamera());
}

On availableCameras I get <0 items>.

If I check the camera is alive
raspistill -o Desktop/image.jpg
it appears and I see a snapshot on the desktop.

Does the library work with a Raspberry Pi camera at all? May be I'm beating a dead horse?

jsulm

@jenya7 I think you will also need to install GStreamer plug-ins. On Linux Qt uses GStreamer for multimedia.

jenya7

@jsulm said in A camera problem.:

@jenya7 I think you will also need to install GStreamer plug-ins. On Linux Qt uses GStreamer for multimedia.

when I run
dpkg -l | grep gstreamer
I see gstreamer installed.

jsulm

@jenya7 said in A camera problem.:

I see gstreamer installed

What exactly is installed? There are many GStreamer plug-ins which may be needed.

jenya7

@jsulm said in A camera problem.:

@jenya7 said in A camera problem.:

I see gstreamer installed

What exactly is installed? There are many GStreamer plug-ins which may be needed.

this is the list

ii  gstreamer1.0-alsa:armhf               1.14.4-2+deb10u1                        armhf        GStreamer plugin for ALSA
ii  gstreamer1.0-gtk3:armhf               1.14.4-1+rpt1+deb10u1                   armhf        GStreamer plugin for GTK+3
ii  gstreamer1.0-libav:armhf              1.15.0.1+git20180723+db823502-2+deb10u1 armhf        libav plugin for GStreamer
ii  gstreamer1.0-omx                      1.14.4-1+rpt1                           armhf        GStreamer OpenMAX plugins
ii  gstreamer1.0-omx-rpi                  1.14.4-1+rpt1                           armhf        OpenMax plugins for GStreamer
ii  gstreamer1.0-omx-rpi-config           1.14.4-1+rpt1                           armhf        OpenMax plugins for GStreamer
ii  gstreamer1.0-plugins-bad:armhf        1.14.4-1+rvt+deb10u2                    armhf        GStreamer plugins from the "bad" set
ii  gstreamer1.0-plugins-base:armhf       1.14.4-2+deb10u1                        armhf        GStreamer plugins from the "base" set
ii  gstreamer1.0-plugins-good:armhf       1.14.4-1+rpt1+deb10u1                   armhf        GStreamer plugins from the "good" set
ii  gstreamer1.0-x:armhf                  1.14.4-2+deb10u1                        armhf        GStreamer plugins for X11 and Pango
ii  libgstreamer-gl1.0-0:armhf            1.14.4-2+deb10u1                        armhf        GStreamer GL libraries
ii  libgstreamer-plugins-bad1.0-0:armhf   1.14.4-1+rvt+deb10u2                    armhf        GStreamer libraries from the "bad" set
ii  libgstreamer-plugins-base1.0-0:armhf  1.14.4-2+deb10u1                        armhf        GStreamer libraries from the "base" set
ii  libgstreamer1.0-0:armhf               1.14.4-1                                armhf        Core GStreamer libraries and elements
ii  libreoffice-avmedia-backend-gstreamer 1:6.1.5-3+rpi1+deb10u7+rpt1             armhf        GStreamer backend for LibreOffice

I really don't know if it's a complete list or a right version.

jsulm

@jenya7 said in A camera problem.:

or a right version

That depends on the Qt version you're using.
Try to also install gstreamer1.0-plugins-ugly, but I don't know whether this will help.

jenya7

@jsulm said in A camera problem.:

@jenya7 said in A camera problem.:

or a right version

That depends on the Qt version you're using.
Try to also install gstreamer1.0-plugins-ugly, but I don't know whether this will help.

I found it out! It's not enough to install library
sudo apt-get install qtmultimedia5-dev
One should add plugins also
sudo apt-get install libqt5multimedia5-plugins

Now it founds the camera. But how do I refer to it later on? There are no fields like name or id or something
at least on debug level

availableCameras	<1 items>	QList<QCameraInfo>
    [0]	@0x1027c8	QCameraInfo
        d	@0x1027c8	QSharedPointer<QCameraInfoPrivate>
			data	@0x10cd88	QCameraInfoPrivate
			weakref	2	int
			strongref	2	int
	availableCameras@1	<optimized out>	
	cameraInfo	@0x1027c8	QCameraInfo &
		d	@0x1027c8	QSharedPointer<QCameraInfoPrivate>
			data	@0x10cd88	QCameraInfoPrivate
			weakref	2	int
			strongref	2	int
	cameraInfo@1	@0x1027c8	QCameraInfo &
		d	@0x1027c8	QSharedPointer<QCameraInfoPrivate>
			data	@0x10cd88	QCameraInfoPrivate
			weakref	2	int
			strongref	2	int

QCameraInfo::defaultCamera()		QCameraInfo
		d		QSharedPointer<QCameraInfoPrivate>
			data	@0x111438	QCameraInfoPrivate
			weakref	1	int
			strongref	1	int

jsulm

@jenya7 said in A camera problem.:

There are no fields like name or id or something

There is: https://doc.qt.io/qt-5/qcamerainfo.html#deviceName

jenya7

@jsulm said in A camera problem.:

@jenya7 said in A camera problem.:

There are no fields like name or id or something

There is: https://doc.qt.io/qt-5/qcamerainfo.html#deviceName

I see. Thank you. I'll try to get it going.

jenya7

something eluding me
To take a shot

void Camera::takeImage()

Then on

connect(m_imageCapture.data(), &QCameraImageCapture::imageCaptured, this, &Camera::processCapturedImage);

void Camera::processCapturedImage(int requestId, const QImage& img)
{
    Q_UNUSED(requestId);
    QImage scaledImage = 100, 100,
                                    Qt::KeepAspectRatio,
                                    Qt::SmoothTransformation);

    ui->lastImagePreviewLabel->setPixmap(QPixmap::fromImage(scaledImage));

    // Display captured image for 4 seconds.
    displayCapturedImage();
    QTimer::singleShot(4000, this, &Camera::displayViewfinder);
}

But where the image actually stored?

SGaist

Hi,

Unless you configure the capture to capture to file, its just going to be in the buffer. You can still save it yourself though.

jenya7

@SGaist said in A camera problem.:

Hi,

Unless you configure the capture to capture to file, its just going to be in the buffer. You can still save it yourself though.

How do I do that? I see m_imageCapture but no property or method to set a path to a file.
And where the buffer located?

SGaist

The buffer just means it's in memory. You'll get a frame to process and then it's up to you to save it.

jenya7

@SGaist said in A camera problem.:

The buffer just means it's in memory. You'll get a frame to process and then it's up to you to save it.

After

g_camera.SetCaptureMode(QCamera::CaptureMode::CaptureStillImage);
g_camera.takeImage();

Nothing happens. I didn't get to

void Camera::processCapturedImage(int requestId, const QImage& img)

or

void Camera::imageSaved(int id, const QString &fileName)

How do I know where is the image (if it was taken at all)?

jsulm

@jenya7 Did you connect a slot to https://doc.qt.io/qt-5/qcamera.html#errorOccurred to see whether you get any errors? Same for https://doc.qt.io/qt-5/qcameraimagecapture.html#error-1
You can get the cptured image using this signal: https://doc.qt.io/qt-5/qcameraimagecapture.html#imageAvailable

jenya7

@jsulm said in A camera problem.:

@jenya7 Did you connect a slot to https://doc.qt.io/qt-5/qcamera.html#errorOccurred to see whether you get any errors? Same for https://doc.qt.io/qt-5/qcameraimagecapture.html#error-1
You can get the cptured image using this signal: https://doc.qt.io/qt-5/qcameraimagecapture.html#imageAvailable

this is what I have

connect(m_imageCapture.data(), &QCameraImageCapture::readyForCaptureChanged, this, &Camera::readyForCapture);
connect(m_imageCapture.data(), &QCameraImageCapture::imageCaptured, this, &Camera::processCapturedImage);
connect(m_imageCapture.data(), &QCameraImageCapture::imageSaved, this, &Camera::imageSaved);
connect(m_imageCapture.data(), QOverload<int, QCameraImageCapture::Error, const QString &>::of(&QCameraImageCapture::error),
            this, &Camera::displayCaptureError);

jsulm

@jenya7 So, what about trying https://doc.qt.io/qt-5/qcameraimagecapture.html#imageAvailable ?

jenya7

@jsulm said in A camera problem.:

@jenya7 So, what about trying https://doc.qt.io/qt-5/qcameraimagecapture.html#imageAvailable ?

I did in Camera::setCamera

connect(m_imageCapture.data(), &QCameraImageCapture::imageAvailable, this, &Camera::ImageAvailable);

and then

void Camera::ImageAvailable(int id, const QVideoFrame &frame)
{
     qDebug() <<  id;
     //qDebug() << frame->???;
}

I also added

void Camera::displayCameraError()
{
    //QMessageBox::warning(this, tr("Camera Error"), m_camera->errorString());
    qDebug() << "Camera Error: " + m_camera->errorString() + "\n";
}

void Camera::displayCaptureError(int id, const QCameraImageCapture::Error error, const QString &errorString)
{
    Q_UNUSED(id);
    Q_UNUSED(error);
    qDebug() << "Image Capture Error: " + errorString;
    m_isCapturingImage = false;
}

and when I do

g_camera.SetCaptureMode(QCamera::CaptureMode::CaptureStillImage);
g_camera.takeImage();

I get

"Image Capture Error: Camera not ready"

How can I know a reason why the camera isn't ready?

jsulm

@jenya7 Did you call

camera->setCaptureMode(QCamera::CaptureStillImage);
camera->start();
//on half pressed shutter button
camera->searchAndLock();

//on shutter button pressed
imageCapture->capture();

like shown in https://doc.qt.io/qt-5/qcameraimagecapture.html ?

jenya7

@jsulm said in A camera problem.:

@jenya7 Did you call
camera->setCaptureMode(QCamera::CaptureStillImage);
camera->start();
//on half pressed shutter button
camera->searchAndLock();

//on shutter button pressed
imageCapture->capture();
like shown in https://doc.qt.io/qt-5/qcameraimagecapture.html ?

I thought

void Camera::takeImage()
{
    m_isCapturingImage = true;
    m_imageCapture->capture();
}

handles all this, kinda higher layer that wraps all together.
and what is
//on half pressed shutter button
//on shutter button pressed
I don't have any buttons. my app is not widget controlled. all commands issued from a command line.
I took a widget camera example (from Examples) and removed all UI related staff.