Problem in static, not in dynamic !

[JulienSmake]

Hello everyone.

I come to you because I made a small test program, so only goal start a camera or webcam device.

My problem, that is good when compiling dynamically, but if I compile in static method I get an error in the launch of my device.

See for yourself.

Dynamically compiled:

I have a led on my test camera, which tells me when it is active, and all is good !

Static compiled:

Here, the LED stays off and i have error message ;'(.

My code:

camera.pro

#-------------------------------------------------
#
# Project created by QtCreator 2015-06-10T19:54:09
#
#-------------------------------------------------
 
QT       += core multimedia
QT       -= gui
 
TARGET = camera
CONFIG   += static
CONFIG   += console
CONFIG   -= app_bundle
 
static {
 CONFIG += static
 DEFINES+= STATIC
}
TEMPLATE = app
 
 
SOURCES += main.cpp \
    camera.cpp
 
HEADERS += \
    camera.h

main.cpp

#include <QCoreApplication>
#include <camera.h>
 
int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);
 
    cameraObj * camera = new cameraObj();
 
    camera->start();
 
    return a.exec();
}

camera.h

#ifndef CAMERA_H
#define CAMERA_H
 
#include <QMultimedia>
#include <QCamera>
#include <QCameraInfo>
 
class cameraObj : public QObject
{
    Q_OBJECT
 
    public:
        explicit cameraObj(QObject *parent = 0);
 
        QCamera* camera;
        QCameraInfo* cameraInfo;
 
    public slots:
        void start();
 
};
 
#endif // CAMERA_H

camera.cpp

#include "camera.h"
 
cameraObj::cameraObj(QObject *parent) : QObject(parent)
{
    camera = new QCamera;
    cameraInfo = new QCameraInfo;
}
 
void cameraObj::start()
{
    qDebug() << cameraInfo->availableCameras();
    qDebug() << cameraInfo->deviceName();
    camera->start();
}

Note that I have no error or warning when compiling my little program, I have compiled Qt static with this script we just found on https://wiki.qt.io/Building_a_static_Qt_for_Windows_using_MinGW

It is the first time I make in static, so I'm a little lost on the processing and resolution of my problem, if a charitable soul can help me I would greatly thankful him :)

Thanks in advance.

[alex_malyu]

Static build has applies limitations and restrictions especially related to plug-in usage.
You might need special handling to enable plug-n or some features might be disabled completely .

[JulienSmake]

@alex_malyu

Hello, and thanks for your answer.

How can I do this ?

[alex_malyu]

Documentation:
http://doc.qt.io/qt-5/plugins-howto.html#static-plugins

and keep in mind that I gave you only possible reason of the failure.

[JulienSmake]

@alex_malyu

Thank you, I'll read it immediately :)

I would add that I have just compile the example provided in the QCamera doccumentation (available here) with changing nothing, and everything starts and runs without problems !

[JulienSmake]

I made the comparison with the example QCamera, and there is no QTPLUGIN or other parameter plugin you can see here.

But I can compile the example in static without problem and all it works great!

So it's a problem in my code :'(.

[JulienSmake]

I found!

Must declare:

QVideoWidget *widget = new QVideoWidget();
camera->setViewfinder(widget);

And after:

camera->start();

And that's all working!