Question about QCameraImageCapture

peterlin82

When I cameraImageCapture1->capture(); about two thousand times.
Program crashes every time.
I don't know how to solve.
Any help would be appreciated!
Sorry for my english.

Information:
Qt 5.3.1
Ubuntu 12.04.4
Logitech C170 webcam
RAM:1G
HDD:1T

@Dialog::Dialog(QWidget *parent) : QDialog(parent),ui(new Ui::Dialog)
{
ui->setupUi(this);

timer1 = new QTimer(this);
connect(timer1, SIGNAL(timeout()), this, SLOT(Ontimer1timeout()));
timer1->start(10000);
camera1 = new QCamera;
cameraImageCapture1 = new QCameraImageCapture(camera1);
QImageEncoderSettings imageEncoderSettings1;
imageEncoderSettings1.setResolution(320,240);
cameraImageCapture1->setEncodingSettings(imageEncoderSettings1);
connect(cameraImageCapture1, SIGNAL(imageCaptured(int,QImage)), this, SLOT(OncameraImageCapture1imageCaptured(int,QImage)));

}

void Dialog::Ontimer1timeout()
{
if((CameraSw==1)&&(cameraImageCapture1->isReadyForCapture())) cameraImageCapture1->capture();
}

void Dialog::OncameraImageCapture1imageCaptured(int,QImage image1)
{
ui->label->setPixmap(QPixmap::fromImage(image1));
}

void Dialog::on_toolButton_clicked()
{
camera1->start();
CameraSw=1;
}

void Dialog::on_toolButton_2_clicked()
{
camera1->stop();
CameraSw=0;
}
@

SGaist

Hi,

What does a run using the debugger tells you ?

peterlin82

sorry.
Not program crashes but operating system crashes.
so without any error message.
The same problem in Raspberry Pi.

抱歉。
不是应用程式当机而是作业系统当机。
所以并没有产生任何错误讯息。
在树莓派中执行也有相同的错误。

SGaist

Just to be sure I understand you correctly, you get your entire OS down by taking pictures ?

peterlin82

Yes,
After cameraImageCapture1->capture(); two thousand times.

SGaist

Did you check with a memory analyzer what as going on ?

peterlin82

I try analyzer.
like this:

!http://sigmaccc.myweb.hinet.net/temp/20140901173.jpg(msg1)!
!http://sigmaccc.myweb.hinet.net/temp/20140901170.jpg(msg2)!

I still don’t know how to solve.
Any help would be appreciated!
thanks a lot.

SGaist

Check with the top command the memory consumption of your application

peterlin82

I try top command.
like this:
!http://sigmaccc.myweb.hinet.net/temp/20140904175.jpg(msg1)!
!http://sigmaccc.myweb.hinet.net/temp/20140904176.jpg(msg2)!

Seems to be a memory problem.
But,I don’t know why.

SGaist

Don't currently know either.

On an unrelated note:

@void OncameraImageCapture1imageCaptured(int,QImage image1)@

should rather be

@void OncameraImageCapture1imageCaptured(int, const QImage& image1)@

peterlin82

I try
(1)void OncameraImageCapture1imageCaptured(int, const QImage &image1)
(2)echo 3 > /proc/sys/vm/drop_caches

 sync

(3)The other webcam(Logitech C270 Webcam)

but the problem persists.

SGaist

Since Qt 5.4 Alpha has been release, can you try with to see if you still experience this ?

On a side note, 1Go of RAM ?

peterlin82

Yes,1 GB RAM.

I try Qt 5.4 Beta.
but the problem persists.

/opt/Qt5.4.0/Examples/Qt-5.4/multimediawidgets/camera
has the same problem too.

SGaist

Then you should take a look at the "bug report system":http://bugreports.qt-project.org to see if it's something known

peterlin82

I find this.

"QTBUG-41606...":https://bugreports.qt-project.org/browse/QTBUG-41606?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel

SGaist,thank you very much.