A camera problem.

jenya7

@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.

jsulm

@jenya7 said in A camera problem.:

I don't have any buttons.

These comments simply tell you that these methods simulate these buttons.
So, yes you have to set the capture mode, start the camera, call searchAndLock and then capture.

jenya7

@jsulm said in A camera problem.:

@jenya7 said in A camera problem.:

I don't have any buttons.

These comments simply tell you that these methods simulate these buttons.
So, yes you have to set the capture mode, start the camera, call searchAndLock and then capture.

I changed to

void Camera::takeImage()
{
    m_camera->start();
    m_camera->searchAndLock();

    m_isCapturingImage = true;
    m_imageCapture->capture();
}

I still have
"Image Capture Error: Camera not ready"
Do I need to set a Viewfinder?
I commented out those lines

//QCameraViewfinder *v_finder = new QCameraViewfinder();
//v_finder->setFixedSize(240, 320);
//v_finder->show();
//v_finder->setAttribute(Qt::WA_NoSystemBackground);
//m_camera->setViewfinder(v_finder);

cause I get an exception on
QCameraViewfinder *v_finder = new QCameraViewfinder();

jsulm

@jenya7 For capturing images view finder should not be needed.
But you could try to enable it to see whether your camera works at all in Qt.
What exception do you get?

jenya7

@jsulm said in A camera problem.:

@jenya7 For capturing images view finder should not be needed.
But you could try to enable it to see whether your camera works at all in Qt.
What exception do you get?

I get
The inferior stopped because it received a signal from the operating system.
Signal name: SIGABRT
Signal meaning: Aborted

jsulm

@jenya7 Please run through debugger and post the stack trace.
Also, you should post your current code with enabled viewfinder.

jenya7

@jsulm said in A camera problem.:

@jenya7 Please run through debugger and post the stack trace.
Also, you should post your current code with enabled viewfinder.

void Camera::setCamera(const QCameraInfo &cameraInfo)
{
    m_camera.reset(new QCamera(cameraInfo));

    connect(m_camera.data(), &QCamera::stateChanged, this, &Camera::updateCameraState);
    connect(m_camera.data(), QOverload<QCamera::Error>::of(&QCamera::error), this, &Camera::displayCameraError);

    m_mediaRecorder.reset(new QMediaRecorder(m_camera.data()));
    connect(m_mediaRecorder.data(), &QMediaRecorder::stateChanged, this, &Camera::updateRecorderState);

    m_imageCapture.reset(new QCameraImageCapture(m_camera.data()));

    connect(m_mediaRecorder.data(), &QMediaRecorder::durationChanged, this, &Camera::updateRecordTime);
    connect(m_mediaRecorder.data(), QOverload<QMediaRecorder::Error>::of(&QMediaRecorder::error),
            this, &Camera::displayRecorderError);

    m_mediaRecorder->setMetaData(QMediaMetaData::Title, QVariant(QLatin1String("Test Title")));

    //connect(ui->exposureCompensation, &QAbstractSlider::valueChanged, this, &Camera::setExposureCompensation);

//here the exception occurs
   QCameraViewfinder *v_finder = new QCameraViewfinder();
    //v_finder->setFixedSize(240, 320);
    //v_finder->show();
    v_finder->setAttribute(Qt::WA_NoSystemBackground);
    m_camera->setViewfinder(v_finder);

    updateCameraState(m_camera->state());
    updateLockStatus(m_camera->lockStatus(), QCamera::UserRequest);
    updateRecorderState(m_mediaRecorder->state());

    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);

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

    connect(m_camera.data(), QOverload<QCamera::LockStatus, QCamera::LockChangeReason>::of(&QCamera::lockStatusChanged),
            this, &Camera::updateLockStatus);

    //ui->captureWidget->setTabEnabled(0, (m_camera->isCaptureModeSupported(QCamera::CaptureStillImage)));
    //ui->captureWidget->setTabEnabled(1, (m_camera->isCaptureModeSupported(QCamera::CaptureVideo)));

    updateCaptureMode(0);
    m_camera->start();
}

and a call stack

1  __GI_raise                                                  raise.c      50  0xb5830f14 
2  __GI_abort                                                  abort.c      79  0xb581c230 
3  QMessageLogger::fatal(const char *, ...) const                               0xb5c1c004 
4  QWidgetPrivate::QWidgetPrivate(int)                                          0xb698e204 
5  QWidget::QWidget(QWidget *, QFlags<Qt::WindowType>)                          0xb69ab42c 
6  QVideoWidget::QVideoWidget(QVideoWidgetPrivate&, QWidget *)                  0xb6f3ed70 
7  QCameraViewfinder::QCameraViewfinder(QWidget *)                              0xb6f388f4 
8  Camera::setCamera                                           camera.cpp   148 0x5a000        //this line is focused
9  Camera::Camera                                              camera.cpp   112 0x599ec    
10 __static_initialization_and_destruction_0                   camera.cpp   69  0x5bd58    
11 _GLOBAL__sub_I_camera.cpp(void)                             camera.cpp   544 0x5bdb4    
12 __libc_csu_init                                                              0xbed54    
13 __libc_start_main                                           libc-start.c 264 0xb581c6ac 
14 _start