Qml2 camera crash on wni7 64bits(simple codes)

stereomatching

Qt version 5.1RC(mingw version)

main.qml
@
import QtQuick 2.0
import QtMultimedia 5.0

Rectangle {
width: 360
height: 360

Camera{
    id: camera
}

VideoOutput {
    id: videoOutput

    anchors.fill: parent
    source: camera
}

}
@

main.cpp
@
#include <QtGui/QGuiApplication>
#include "qtquick2applicationviewer.h"

int main(int argc, char *argv[])
{
QGuiApplication app(argc, argv);

QtQuick2ApplicationViewer viewer;
viewer.setMainQmlFile&#40;QStringLiteral("qml/qmlCameraTest/main.qml"&#41;);
viewer.showExpanded();

return app.exec();

}
@

I create a quick2 project by QtCreator, this is the .pro file

@
folder_01.source = qml/qmlCameraTest
folder_01.target = qml
DEPLOYMENTFOLDERS = folder_01

QT += quick qml multimedia

SOURCES += main.cpp

include(qtquick2applicationviewer/qtquick2applicationviewer.pri)
qtcAddDeployment()

@

error message

QWidget: Cannot create a QWidget without QApplication
Invalid parameter passed to C runtime function.
Invalid parameter passed to C runtime function.

The QCamera works fine, but the Camera(quick2) crash
Anyone has the same problem?