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

[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

[GrecKo]

How did you add QZXing to your project?
https://github.com/ftylitak/qzxing#howToInclude has instructions on how to do it

[Melle_87]

@GrecKo: Okay. Now I am able to use the QZXingFilter in VideoOutput.
But the conversion from QVideoFrame to QImage is not successful.
QZXingFilter says:

QZXingFilterRunnable error: Cant create image file to process.
Maybe it was a format conversion problem? 
VideoFrame format:  Format_YUYV
Image corresponding format:  QImage::Format_Invalid

What should I do now???

[Melle_87]

It was my fault. I pulled the latest version of QZXing. Now the conversion from QVideoFrame to QImage is working.