QCamera Problems!

[SGaist]

You should check the QtMultimedia plugin with ldd to see if it finds the gstreamer libraries. It might be still using the 0.1 version.

[Hasan Vaez]

@SGaist said in QCamera Problems!:

check the QtMultimedia plugin with ldd

Thank you SGaist, there is no EXEC file in gstreamer plugin folder. With ldd we can just check exec dependency Libs.
Would you please tell me how to check Lib dependency of Qt Plugins?

[Hasan Vaez]

@SGaist said in QCamera Problems!:

QtMultimedia

[jsulm]

@Hasan-Vaez said in QCamera Problems!:

With ldd we can just check exec dependency Libs.

This is wrong. ldd works with libs as well

[SGaist]

You are mixing your distribution provided Qt with the one you installed through the online installer. They are two different versions of Qt hence my question about the libraries linked to your 5.10 version of the gstreamer plugin.

[Hasan Vaez]

@jsulm I know. Where is lib (SO file) in Multimedia plugin?

[jsulm]

@Hasan-Vaez For camera:

ldd ~/Qt/5.10.0/gcc_64/plugins/mediaservice/libgstcamerabin.so 

[Hasan Vaez]

@SGaist Thank you for your reply and trying to solve this maybe bug.
I did not install GStreamer after installing QT.

I try to setup a new Ubuntu 16.04LTS in VMWare machine + QT5.10.0 again and run the example of QCamera which is in part of the Qt package and see what happened.

[Hasan Vaez]

@SGaist said in QCamera Problems!:

with

I installed a new Ubuntu 14.04 LTS, Qt5.10.0 (Offline installer).
Also installed some essential PKGs for running Camera: mesa-common-dev, libpulse-dev, libgl1-mesa-dev

But problem is remained!!!

Mr. Gsaist, did you tried? : https://doc.qt.io/qt-5.10/qtmultimedia-multimediawidgets-camera-example.html

Would you please make a run the QCamera example from QT example folder.

[mranger90]

If you are running from a VMware machine, you could have problems accessing the camera.
Make sure that the camera is not connected to the host.
See the "Player | Removable Devices | ..." menu option of VMware player.
Also, if its connect to the usb you may have to downgrade from usb3.0 to sub 2.0 or even usb 1.1 from the player settings menu.

[Hasan Vaez]

@mranger90
Thank you, but I think you do not read my full description in the top.
I tested it in another PC without VM.

[mrjj]

@Hasan-Vaez said in QCamera Problems!:

Unable to query the parameter info: "Invalid argument"

Google that suggest something with the gstreamer. but im not 100% sure.

Anyway, i would test the camera in the same linux using some linux camera program to verify something can see it.
https://www.linuxlinks.com/webcam/

[Hasan Vaez]

Just tell me, you do not having any problem with Camera with QT C++ in linux?

[mranger90]

I've been able to use it many time with various Linuxi and through several Qt releases.
Are you able to use the camera outside of Qt, for example with the Cheese app ?

[Hasan Vaez]

@mranger90
Thank you for your reply.
Yes, I can use it outside of QT. I tested it with Cheese app in Ubuntu 16.04 LTS without any problem.
I also have not any problem in other OS like MAC and WINDOWS.

[Hasan Vaez]

@mranger90
Please tell me what plugins did you install for qmultimedia in QT5?

[mranger90]

Unfortunately I don't have any of those systems in front of me now and won't until Monday.
Off the top of my head I'm pretty sure I've installed libgstreamerdev and maybe gstpluginsbase?
Not sure of the exact package names.

[mranger90]

Ok, I just set up an Ubuntu 16.04 VM with VMWare on my pathetically underpowered home system which is running Win 10 as the native OS.
Installed Qt 5.10.0.
Have a Microsoft LifeCam HD-600 usb camera.
VMWare is set up to use USB 1.1.
Cheese can access and display the camera.
To build the Examples/multimediaWidgets/camera project I had to install:
libgl-mesa-dev
mesa-common-dev
libpulse-dev

Other than a little fiddling with the camera parameters that's all I had to do to get it to work on a stock ubuntu 16.04 install.
I'd have to dig out some of my other apps to test with, but it looks like this should work for you. If you can post a more complete set of your code I'd be happy to test it tomorrow.

[Hasan Vaez]

@mranger90 said in QCamera Problems!:

libpulse-dev

Thank you arranger for your comments.
I install another Ubuntu 16.04, Qt5.10.0 (along with 3 components: libgl1-mesa-dev mesa-common-dev libpulse-dev)
Test the Camera example with VMWARE MAC CAM and also with LOGITEC CAM.

The problem remained!

My codes are:
1- Camera example in QT folder
2- The following simple codes:

QCamera *Camera;
QCameraImageCapture *ImageCapture;
QCameraInfo *CameraInfo;

void MainWindow::on_pushButton_clicked()
{
Camera = new QCamera;
ImageCapture = new QCameraImageCapture(Camera);

Camera->setViewfinder(ui->wCamera);
ui->wCamera->setAspectRatioMode(Qt::KeepAspectRatioByExpanding);
Camera->setCaptureMode(QCamera::CaptureViewfinder);
Camera->start();
}

All things seems to be correct, there should be a small point which I don't know what is it??

[mranger90]

ok, Heres the simplest code I could create that runs with my setup:
Mainwindow.h

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include <QCamera>

namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    explicit MainWindow(QWidget *parent = 0);
    ~MainWindow();

private slots:
    void on_actionStart_triggered();

private:
    Ui::MainWindow *ui;
    QCamera *m_camera;
};

#endif // MAINWINDOW_H

mainwindow.cpp

#include "mainwindow.h"
#include "ui_mainwindow.h"

#include <QVideoWidget>
#include <QCameraInfo>
#include <QCameraViewfinderSettings>
#include <QDebug>

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

    // get a list of available cameras
    QList<QCameraInfo> cameras = QCameraInfo::availableCameras();
    // just pick the first
    if (cameras.size() > 0) {
        qDebug() << "creating camera from " << cameras.at(0).deviceName() << cameras.at(0).description();
        m_camera = new QCamera(cameras.at(0));
        if (m_camera) {
            m_camera->setViewfinder(videoDisplay);
            m_camera->setCaptureMode(QCamera::CaptureViewfinder);
            QCameraViewfinderSettings settings = m_camera->viewfinderSettings();
            // change resolution to 320x240
            settings.setResolution(QSize(320,240));
            m_camera->setViewfinderSettings(settings);


        }
    }
}

MainWindow::~MainWindow()
{
    delete ui;
}

void MainWindow::on_actionStart_triggered()
{
    if (m_camera) {
        m_camera->start();
    }
}

camtest.pro

QT       += core gui multimedia multimediawidgets

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

TARGET = camtest
TEMPLATE = app

DEFINES += QT_DEPRECATED_WARNINGS
SOURCES += \
        main.cpp \
        mainwindow.cpp

HEADERS += \
        mainwindow.h

FORMS += \
        mainwindow.ui

Mainwindow is just a stock MainWindow with a menu item to start video capture.

Let me know if this works.