After convertion QVideoFrame to QImage, the QImage is zoomed and streched

jsulm

@Melle_87 How do you show the image?
Please show the code.

Melle_87

This post is deleted!

Melle_87

Rectangle {
        id: videoOutput
        z:99
        color: Style.buttonBackground
        VideoOutput {
            id: vid
            source: camera
            filters: [ camera.filt ]
            visible: true
            anchors.fill: parent
        }
    }

    Camera {
        id: camera
        deviceId: "/dev/video0"
        viewfinder.resolution: "640x480"
        viewfinder.maximumFrameRate: 10
        viewfinder.minimumFrameRate: 10
        exposure.exposureMode: Camera.ExposureManual
        exposure.manualAperture: 16
        exposure.manualShutterSpeed: 1/100
        exposure.manualIso: -1
    }

    MyVideoFilter {
        id: myFilter
    }

This is the live stream in the GUI:

And this is the saved image after convertion:

I have to mention that everything has worked fine on the Raspberry pi 3 with Raspbian Stretch.

GrecKo

The important part of your code is the QVideoFrame to QImage conversion.

Melle_87

@GrecKo:

QByteArray data;
QSize size;
QVideoFrame::PixelFormat pixelFormat;
int bytesPerLine;

void copyData(QVideoFrame & frame)
{
    frame.map(QAbstractVideoBuffer::ReadOnly);

    if(data.size() != frame.mappedBytes()) {
        data.resize(frame.mappedBytes());
    }

    memcpy(data.data(), frame.bits(), frame.mappedBytes());
    size = frame.size();
    pixelFormat = frame.pixelFormat();
    bytesPerLine = frame.bytesPerLine();

    frame.unmap();
}

QVideoFrame MyVideoFilterRunnable::run(QVideoFrame *input, const QVideoSurfaceFormat &surfaceFormat, RunFlags flags)
{  
    Q_UNUSED(surfaceFormat);
    Q_UNUSED(flags);

    if(!input || !input->isValid())
        return *input;

    m_filter->m_frame.copyData(*input);
    m_filter->m_processThread = QtConcurrent::run(this, &MyVideoFilterRunnable::processVideoFrame, m_filter->m_frame);

    return * input;
}

void MyVideoFilterRunnable::processVideoFrame(MyVideoFrame &videoFrame)
{
    QImage img((const uchar*)(videoFrame.data.data()), videoFrame.size.width(), videoFrame.size.height(), videoFrame.bytesPerLine, QImage::Format_Indexed8);
    img.save("/path/img.png");
    ...
}

Melle_87

@GrecKo: Do you have any ideas what could be the problem here?

GrecKo

Since you are copying raw data from the QVideoFrame to the QImage, I think there is format issue.

I guess QImage::Format_Indexed8 is the wrong format. Have you check the pixel format of the QVideoFrame?

Melle_87

@GrecKo: Pixel format of the QVideoFrame is QVideoFrame::Format_YUYV (21). But this is not available when I am creating my QImage. Which pixel format do I have to use instead of QImage::Format_Indexed8?

GrecKo

Some ideas here : https://stackoverflow.com/questions/27829830/convert-qvideoframe-to-qimage

SGaist

Hi,

To add to @GrecKo, YUYV is not directly mappable to an indexed image format.

What exactly are you trying to achieve ?

fcarney

@SGaist This talks about converting YUV to RGB. Is this the same as UYUV?

SGaist

YUV is a color space as is RGB, YUYV is one of the many possible ways to store YUV data like you have RGB, BGR, etc.

Melle_87

@SGaist: I want to detect barcodes. Therefore I use ZBar and QZXing.
For both I need a data of a QImage. That is the reason why I have to convert the QVideoFrame to QImage.

Melle_87

@SGaist: But what could be the explanation that everything was fine on Raspberry Pi 3 with Raspbian Stretch and now I have problems on Raspberry Pi 4 with Raspbian Buster?

GrecKo

@Melle_87 said in After convertion QVideoFrame to QImage, the QImage is zoomed and streched:

@SGaist: But what could be the explanation that everything was fine on Raspberry Pi 3 with Raspbian Stretch and now I have problems on Raspberry Pi 4 with Raspbian Buster?

My guess is that the Pi 3 was providing frames in a different format.

GrecKo

@Melle_87 said in After convertion QVideoFrame to QImage, the QImage is zoomed and streched:

@SGaist: I want to detect barcodes. Therefore I use ZBar and QZXing.
For both I need a data of a QImage. That is the reason why I have to convert the QVideoFrame to QImage.

QZXing is supposed to handle YUYV fine in its video filters : https://github.com/ftylitak/qzxing/blob/master/src/QZXingFilter.cpp#L325

Melle_87

@GrecKo: Thank for the link. I tried to register QZXingFilter in main.cpp:

qmlRegisterType<QZXingFilter>("MY.QZXingFilter", 1, 0, "MyQZXingFilter");

Then I importet it in my qml file, instatiated it and assigned to my VideoOutput:

import MY.QZXingFilter 1.0

MyQZXingFilter {
    id: myBarcodeFilter
}

My_Camera {
    id: camera
}
   
VideoOutput {
    id: vid
    source: camera
    filters: [ myBarcodeFilter ]   
}

But now I get some errors.

/opt/raspi-tools-8.3.0/lib/gcc/arm-linux-gnueabihf/8.3.0/../../../../arm-linux-gnueabihf/bin/ld: main.o: in function `int qmlRegisterType<QZXingFilter>(char const*, int, int, char const*)':
/home/m/Builds/build_PY-Raspi_Buster-Debug/../../../x/workspace/gateway-setup/qt-for-raspi4-root-buster-pi3-vc4-tc5/qt5pi/include/QtQml/qqml.h:311: undefined reference to `QZXingFilter::staticMetaObject'
/opt/raspi-tools-8.3.0/lib/gcc/arm-linux-gnueabihf/8.3.0/../../../../arm-linux-gnueabihf/bin/ld: main.o: in function `QQmlPrivate::QQmlElement<QZXingFilter>::QQmlElement()':
/home/m/Builds/build_PY-Raspi_Buster-Debug/../../../x/workspace/gateway-setup/qt-for-raspi4-root-buster-pi3-vc4-tc5/qt5pi/include/QtQml/qqmlprivate.h:103: undefined reference to `QZXingFilter::QZXingFilter(QObject*)'
/opt/raspi-tools-8.3.0/lib/gcc/arm-linux-gnueabihf/8.3.0/../../../../arm-linux-gnueabihf/bin/ld: main.o: in function `QtPrivate::MetaObjectForType<QZXingFilter*, void>::value()':
/home/m/Builds/build_PY-Raspi_Buster-Debug/../../../x/workspace/gateway-setup/qt-for-raspi4-root-buster-pi3-vc4-tc5/qt5pi/include/QtCore/qmetatype.h:1476: undefined reference to `QZXingFilter::staticMetaObject'
/opt/raspi-tools-8.3.0/lib/gcc/arm-linux-gnueabihf/8.3.0/../../../../arm-linux-gnueabihf/bin/ld: main.o: in function `QMetaTypeIdQObject<QZXingFilter*, 8>::qt_metatype_id()':
/home/m/Builds/build_PY-Raspi_Buster-Debug/../../../x/workspace/gateway-setup/qt-for-raspi4-root-buster-pi3-vc4-tc5/qt5pi/include/QtCore/qmetatype.h:1841: undefined reference to `QZXingFilter::staticMetaObject'
/opt/raspi-tools-8.3.0/lib/gcc/arm-linux-gnueabihf/8.3.0/../../../../arm-linux-gnueabihf/bin/ld: main.o:(.data.rel.ro._ZTVN11QQmlPrivate11QQmlElementI12QZXingFilterEE[_ZTVN11QQmlPrivate11QQmlElementI12QZXingFilterEE]+0x8): undefined reference to `QZXingFilter::metaObject() const'
/opt/raspi-tools-8.3.0/lib/gcc/arm-linux-gnueabihf/8.3.0/../../../../arm-linux-gnueabihf/bin/ld: main.o:(.data.rel.ro._ZTVN11QQmlPrivate11QQmlElementI12QZXingFilterEE[_ZTVN11QQmlPrivate11QQmlElementI12QZXingFilterEE]+0xc): undefined reference to `QZXingFilter::qt_metacast(char const*)'
/opt/raspi-tools-8.3.0/lib/gcc/arm-linux-gnueabihf/8.3.0/../../../../arm-linux-gnueabihf/bin/ld: main.o:(.data.rel.ro._ZTVN11QQmlPrivate11QQmlElementI12QZXingFilterEE[_ZTVN11QQmlPrivate11QQmlElementI12QZXingFilterEE]+0x10): undefined reference to `QZXingFilter::qt_metacall(QMetaObject::Call, int, void**)'
/opt/raspi-tools-8.3.0/lib/gcc/arm-linux-gnueabihf/8.3.0/../../../../arm-linux-gnueabihf/bin/ld: main.o:(.data.rel.ro._ZTVN11QQmlPrivate11QQmlElementI12QZXingFilterEE[_ZTVN11QQmlPrivate11QQmlElementI12QZXingFilterEE]+0x38): undefined reference to `QZXingFilter::createFilterRunnable()'
/opt/raspi-tools-8.3.0/lib/gcc/arm-linux-gnueabihf/8.3.0/../../../../arm-linux-gnueabihf/bin/ld: main.o:(.data.rel.ro._ZTIN11QQmlPrivate11QQmlElementI12QZXingFilterEE[_ZTIN11QQmlPrivate11QQmlElementI12QZXingFilterEE]+0x8): undefined reference to `typeinfo for QZXingFilter'
/opt/raspi-tools-8.3.0/lib/gcc/arm-linux-gnueabihf/8.3.0/../../../../arm-linux-gnueabihf/bin/ld: main.o: in function `QQmlPrivate::QQmlElement<QZXingFilter>::~QQmlElement()':
/home/m/Builds/build_PY-Raspi_Buster-Debug/../../../x/workspace/gateway-setup/qt-for-raspi4-root-buster-pi3-vc4-tc5/qt5pi/include/QtQml/qqmlprivate.h:108: undefined reference to `QZXingFilter::~QZXingFilter()'

Do you know what I am doing wrong?

jsulm

@Melle_87 said in After convertion QVideoFrame to QImage, the QImage is zoomed and streched:

MyQZXingFilter

Is it derived from QObject?

Melle_87

@jsulm: It is derived from QAbstractVideoFilter.

jsulm

@Melle_87 Then I guess you do not build/link moc_*.cpp file for MyQZXingFilter

undefined reference to `QZXingFilter::QZXingFilter(QObject*)' - actually you seem to not link QZXingFilter at all