Issues with Building OpenCV for Android using Qt 6.4.2 on Windows 10

Kaguro

Hi Guys!

I'm trying to build and use OpenCV for Android in my Qt 6.4.2 project on Windows 10, but I'm running into some issues.

Here’s what I’ve done so far:

I added OpenCV in my project (pro file) like this:

INCLUDEPATH += F:/Asztal/VP/OpenCV-android-sdk/sdk/native/jni/include/

LIBS += \
        -L"F:/Asztal/VP/OpenCV-android-sdk/sdk/native/3rdparty/libs/armeabi-v7a/" \
        -L"F:/Asztal/VP/OpenCV-android-sdk/sdk/native/libs/armeabi-v7a/" \
        -L"F:/Asztal/VP/OpenCV-android-sdk/sdk/native/staticlibs/armeabi-v7a/" \
        -lopencv_core \
        -lopencv_highgui \
        -lopencv_imgproc \
        -lopencv_imgcodecs \
        -lopencv_features2d \
        -lopencv_calib3d

I attempted to use OpenCV functions, like this:

#include <opencv2/opencv.hpp>
cv::Mat QImageToCvMat(const QImage &image) {
    return cv::Mat(image.height(), image.width(), CV_8UC4,
                   (void*)image.constBits(), image.bytesPerLine()).clone();
}

QImage CvMatToQImage(const cv::Mat &mat) {
    return QImage(mat.data, mat.cols, mat.rows, mat.step, QImage::Format_RGBA8888).copy();
}

QImage upscaleWithOpenCV(const QImage &image, int newWidth, int newHeight) {
    cv::Mat mat = QImageToCvMat(image);
    cv::Mat resizedMat;
    cv::resize(mat, resizedMat, cv::Size(newWidth, newHeight), 0, 0, cv::INTER_LANCZOS4);
    return CvMatToQImage(resizedMat);
}

//using:
QLabel *lajos = new QLabel();
QImage betterScaledImage = upscaleWithOpenCV(preview, this->width(), this->height());
lajos->setPixmap(QPixmap::fromImage(betterScaledImage));
lajos->show();

The include is correct because, I didnt get error then. But When I try to rebuild I get these errors:

I’ve tried different approaches, but I haven’t been able to resolve the issue. Has anyone successfully built OpenCV for Android using Qt on Windows? Any advice or guidance would be greatly appreciated!

Thanks in advance!

jsulm

@Kaguro Please post errors as text, not picture.
You should look for the very first error.
Also check to which libraries the symbols belong which are not found.

Kaguro

@jsulm okay sorry these errors kinda same:

ld: error: undefined symbol: carotene_o4t::isSupportedConfiguration()
>>> referenced by arithm.dispatch.cpp
>>>               arithm.dispatch.cpp.o:(cv::hal::add8u(unsigned char const*, unsigned int, unsigned char const*, unsigned int, unsigned char*, unsigned int, int, int, void*)) in archive F:/Asztal/VP/new/OpenCV-android-sdk/sdk/native/staticlibs/armeabi-v7a/libopencv_core.a
>>> referenced by arithm.dispatch.cpp
>>>               arithm.dispatch.cpp.o:(cv::hal::add8s(signed char const*, unsigned int, signed char const*, unsigned int, signed char*, unsigned int, int, int, void*)) in archive F:/Asztal/VP/new/OpenCV-android-sdk/sdk/native/staticlibs/armeabi-v7a/libopencv_core.a

(the path is a little different, because I tried some changes)

jsulm

@Kaguro said in Issues with Building OpenCV for Android using Qt 6.4.2 on Windows 10:

armeabi-v7a

I'm not sure this is the correct ABI. Check the ABI of your Android Qt installation, it is probably v8a. ABIs must match.

Kaguro

@jsulm Its armeabi-v7a I checked. I always build with this to android

Kaguro

@jsulm I download from there:
https://github.com/opencv/opencv/releases/tag/4.11.0
the "opencv-4.11.0-android-sdk" And I just use it... this can be the problem?

jsulm

@Kaguro Then look in the build log for linker warnings: if some libs are incompatible you will get warning.
And as I suggested before: check which libraries provide the symbols which are not found and then check whether you link these libs.
For example carotene_o4t::isSupportedConfiguration seems to come from libtegra_hal (see https://stackoverflow.com/questions/41665655/what-is-carotene-o4t-and-why-does-it-cause-issues-with-compiling-a-program-using).

jsulm

@Kaguro said in Issues with Building OpenCV for Android using Qt 6.4.2 on Windows 10:

this can be the problem?

It can if the ABIs do not match.

Kaguro

@jsulm
so I try this now:

LIBS += \
        -L"F:/Asztal/VP/mew/OpenCV-android-sdk/sdk/native/3rdparty/libs/armeabi-v7a/" \
        -L"F:/Asztal/VP/new/OpenCV-android-sdk/sdk/native/libs/armeabi-v7a/" \
        -L"F:/Asztal/VP/new/OpenCV-android-sdk/sdk/native/staticlibs/armeabi-v7a/" \
        -LF:/Asztal/VP/new/OpenCV-android-sdk/sdk/native/staticlibs/armeabi-v7a -lopencv_core \
        -LF:/Asztal/VP/new/OpenCV-android-sdk/sdk/native/staticlibs/armeabi-v7a -lopencv_dnn \
        -LF:/Asztal/VP/new/OpenCV-android-sdk/sdk/native/staticlibs/armeabi-v7a -lopencv_flann \
        -LF:/Asztal/VP/new/OpenCV-android-sdk/sdk/native/staticlibs/armeabi-v7a -lopencv_highgui \
        -LF:/Asztal/VP/new/OpenCV-android-sdk/sdk/native/staticlibs/armeabi-v7a -lopencv_gapi \
        -LF:/Asztal/VP/new/OpenCV-android-sdk/sdk/native/staticlibs/armeabi-v7a -lopencv_ml \
        -LF:/Asztal/VP/new/OpenCV-android-sdk/sdk/native/staticlibs/armeabi-v7a -lopencv_objdetect \
        -LF:/Asztal/VP/new/OpenCV-android-sdk/sdk/native/staticlibs/armeabi-v7a -lopencv_photo \
        -LF:/Asztal/VP/new/OpenCV-android-sdk/sdk/native/staticlibs/armeabi-v7a -lopencv_imgproc \
        -LF:/Asztal/VP/new/OpenCV-android-sdk/sdk/native/staticlibs/armeabi-v7a -lopencv_imgcodecs \
        -LF:/Asztal/VP/new/OpenCV-android-sdk/sdk/native/staticlibs/armeabi-v7a -lopencv_features2d \
        -LF:/Asztal/VP/new/OpenCV-android-sdk/sdk/native/staticlibs/armeabi-v7a -lopencv_calib3d \
        -LF:/Asztal/VP/new/OpenCV-android-sdk/sdk/native/staticlibs/armeabi-v7a -lopencv_video \
        -LF:/Asztal/VP/new/OpenCV-android-sdk/sdk/native/staticlibs/armeabi-v7a -lopencv_videoio \
        -LF:/Asztal/VP/new/OpenCV-android-sdk/sdk/native/3rdparty/libs/armeabi-v7a -ltegra_hal \
        -LF:/Asztal/VP/new/OpenCV-android-sdk/sdk/native/staticlibs/armeabi-v7a -lopencv_stitching \
        -LF:/Asztal/VP/new/OpenCV-android-sdk/sdk/native/3rdparty/libs/armeabi-v7a -ltbb

And now I got "only" 15 errors for example:
:-1: error: error: undefined symbol: android_getCpuFeatures
:-1: error: error: undefined symbol: __itt_thread_set_name_ptr__3_0
:-1: error: error: undefined symbol: __itt_string_handle_create_ptr__3_0
(etc..)

And it looks like this is from libopencv_core. But I already linked the libopencv_core

jsulm

@Kaguro Did you check whether there are any linker warning about incompatible libraries?
You should also check the linker call to make sure all the libs were passed to it.

Kaguro

@jsulm Sorry I am really a beginner and I don't understand exactly what you would ask for.
I just see errors and this is the whole log what I see :

C:\Users\Kaguro\AppData\Local\Android\Sdk\ndk\23.1.7779620/toolchains/llvm/prebuilt/windows-x86_64/bin/clang++ -target armv7a-linux-androideabi23 -fno-limit-debug-info -Wl,--exclude-libs,libunwind.a -Wl,-soname,libPoorMans_thatsyou_client_armeabi-v7a.so -Wl,--build-id=sha1 -Wl,--no-undefined -Wl,-z,noexecstack -shared -o libPoorMans_thatsyou_client_armeabi-v7a.so  @object_script.libPoorMans_thatsyou_client_armeabi-v7a.so   -LF:/Asztal/VP/mew/OpenCV-android-sdk/sdk/native/3rdparty/libs/armeabi-v7a/ -LF:/Asztal/VP/new/OpenCV-android-sdk/sdk/native/libs/armeabi-v7a/ -LF:/Asztal/VP/new/OpenCV-android-sdk/sdk/native/staticlibs/armeabi-v7a/ -LF:/Asztal/VP/new/OpenCV-android-sdk/sdk/native/staticlibs/armeabi-v7a -lopencv_core -lopencv_dnn -lopencv_flann -lopencv_highgui -lopencv_gapi -lopencv_ml -lopencv_objdetect -lopencv_photo -lopencv_imgproc -lopencv_imgcodecs -lopencv_features2d -lopencv_calib3d -lopencv_video -lopencv_videoio -LF:/Asztal/VP/new/OpenCV-android-sdk/sdk/native/3rdparty/libs/armeabi-v7a -ltegra_hal -lopencv_stitching -ltbb D:/Qt/6.4.2/android_armv7/lib/libQt6MultimediaWidgets_armeabi-v7a.so D:/Qt/6.4.2/android_armv7/lib/libQt6Multimedia_armeabi-v7a.so D:/Qt/6.4.2/android_armv7/lib/libQt6Widgets_armeabi-v7a.so D:/Qt/6.4.2/android_armv7/lib/libQt6Gui_armeabi-v7a.so -lEGL D:/Qt/6.4.2/android_armv7/lib/libQt6Network_armeabi-v7a.so D:/Qt/6.4.2/android_armv7/lib/libQt6Core_armeabi-v7a.so -llog -pthread -lGLESv2   -llog -lz -lm -ldl -lc
ld: error: undefined symbol: android_getCpuFeatures
>>> referenced by system.cpp
>>>               system.cpp.o:(cv::HWFeatures::initialize()) in archive F:/Asztal/VP/new/OpenCV-android-sdk/sdk/native/staticlibs/armeabi-v7a/libopencv_core.a

ld: error: undefined symbol: __itt_thread_set_name_ptr__3_0
>>> referenced by system.cpp
>>>               system.cpp.o:(cv::TLSData<cv::(anonymous namespace)::ThreadID>::createDataInstance() const) in archive F:/Asztal/VP/new/OpenCV-android-sdk/sdk/native/staticlibs/armeabi-v7a/libopencv_core.a

ld: error: undefined symbol: __itt_string_handle_create_ptr__3_0
>>> referenced by trace.cpp
>>>               trace.cpp.o:(cv::utils::trace::details::Region::LocationExtraData::LocationExtraData(cv::utils::trace::details::Region::LocationStaticStorage const&)) in archive F:/Asztal/VP/new/OpenCV-android-sdk/sdk/native/staticlibs/armeabi-v7a/libopencv_core.a
>>> referenced by trace.cpp
>>>               trace.cpp.o:(cv::utils::trace::details::Region::Impl::leaveRegion(cv::utils::trace::details::TraceManagerThreadLocal&)) in archive F:/Asztal/VP/new/OpenCV-android-sdk/sdk/native/staticlibs/armeabi-v7a/libopencv_core.a
>>> referenced by trace.cpp
>>>               trace.cpp.o:(cv::utils::trace::details::TraceManager::TraceManager()) in archive F:/Asztal/VP/new/OpenCV-android-sdk/sdk/native/staticlibs/armeabi-v7a/libopencv_core.a
>>> referenced 1 more times

ld: error: undefined symbol: __itt_api_version_ptr__3_0
>>> referenced by trace.cpp
>>>               trace.cpp.o:(cv::utils::trace::details::isITTEnabled()) in archive F:/Asztal/VP/new/OpenCV-android-sdk/sdk/native/staticlibs/armeabi-v7a/libopencv_core.a

ld: error: undefined symbol: __itt_domain_create_ptr__3_0
>>> referenced by trace.cpp
>>>               trace.cpp.o:(cv::utils::trace::details::isITTEnabled()) in archive F:/Asztal/VP/new/OpenCV-android-sdk/sdk/native/staticlibs/armeabi-v7a/libopencv_core.a

ld: error: undefined symbol: __itt_id_create_ptr__3_0
>>> referenced by trace.cpp
>>>               trace.cpp.o:(cv::utils::trace::details::Region::Impl::Impl(cv::utils::trace::details::TraceManagerThreadLocal&, cv::utils::trace::details::Region*, cv::utils::trace::details::Region&, cv::utils::trace::details::Region::LocationStaticStorage const&, long long)) in archive F:/Asztal/VP/new/OpenCV-android-sdk/sdk/native/staticlibs/armeabi-v7a/libopencv_core.a
>>> referenced by trace.cpp
>>>               trace.cpp.o:(cv::utils::trace::details::Region::Impl::registerRegion(cv::utils::trace::details::TraceManagerThreadLocal&)) in archive F:/Asztal/VP/new/OpenCV-android-sdk/sdk/native/staticlibs/armeabi-v7a/libopencv_core.a

ld: error: undefined symbol: __itt_task_begin_ptr__3_0
>>> referenced by trace.cpp
>>>               trace.cpp.o:(cv::utils::trace::details::Region::Impl::enterRegion(cv::utils::trace::details::TraceManagerThreadLocal&)) in archive F:/Asztal/VP/new/OpenCV-android-sdk/sdk/native/staticlibs/armeabi-v7a/libopencv_core.a

ld: error: undefined symbol: __itt_id_destroy_ptr__3_0
>>> referenced by trace.cpp
>>>               trace.cpp.o:(cv::utils::trace::details::Region::Impl::~Impl()) in archive F:/Asztal/VP/new/OpenCV-android-sdk/sdk/native/staticlibs/armeabi-v7a/libopencv_core.a

ld: error: undefined symbol: __itt_metadata_add_ptr__3_0
>>> referenced by trace.cpp
>>>               trace.cpp.o:(cv::utils::trace::details::Region::Impl::leaveRegion(cv::utils::trace::details::TraceManagerThreadLocal&)) in archive F:/Asztal/VP/new/OpenCV-android-sdk/sdk/native/staticlibs/armeabi-v7a/libopencv_core.a
>>> referenced by trace.cpp
>>>               trace.cpp.o:(cv::utils::trace::details::traceArg(cv::utils::trace::details::TraceArg const&, int)) in archive F:/Asztal/VP/new/OpenCV-android-sdk/sdk/native/staticlibs/armeabi-v7a/libopencv_core.a
>>> referenced by trace.cpp
>>>               trace.cpp.o:(cv::utils::trace::details::traceArg(cv::utils::trace::details::TraceArg const&, long long)) in archive F:/Asztal/VP/new/OpenCV-android-sdk/sdk/native/staticlibs/armeabi-v7a/libopencv_core.a
>>> referenced 1 more times

ld: error: undefined symbol: __itt_task_end_ptr__3_0
>>> referenced by trace.cpp
>>>               trace.cpp.o:(cv::utils::trace::details::Region::Impl::leaveRegion(cv::utils::trace::details::TraceManagerThreadLocal&)) in archive F:/Asztal/VP/new/OpenCV-android-sdk/sdk/native/staticlibs/armeabi-v7a/libopencv_core.a

ld: error: undefined symbol: __itt_region_begin_ptr__3_0
>>> referenced by trace.cpp
>>>               trace.cpp.o:(cv::utils::trace::details::TraceManager::TraceManager()) in archive F:/Asztal/VP/new/OpenCV-android-sdk/sdk/native/staticlibs/armeabi-v7a/libopencv_core.a

ld: error: undefined symbol: __itt_region_end_ptr__3_0
>>> referenced by trace.cpp
>>>               trace.cpp.o:(cv::utils::trace::details::TraceManager::~TraceManager()) in archive F:/Asztal/VP/new/OpenCV-android-sdk/sdk/native/staticlibs/armeabi-v7a/libopencv_core.a

ld: error: undefined symbol: __itt_relation_add_ptr__3_0
>>> referenced by trace.cpp
>>>               trace.cpp.o:(cv::utils::trace::details::parallelForAttachNestedRegion(cv::utils::trace::details::Region const&)) in archive F:/Asztal/VP/new/OpenCV-android-sdk/sdk/native/staticlibs/armeabi-v7a/libopencv_core.a

ld: error: undefined symbol: __itt_metadata_str_add_ptr__3_0
>>> referenced by trace.cpp
>>>               trace.cpp.o:(cv::utils::trace::details::traceArg(cv::utils::trace::details::TraceArg const&, char const*)) in archive F:/Asztal/VP/new/OpenCV-android-sdk/sdk/native/staticlibs/armeabi-v7a/libopencv_core.a
clang++: error: linker command failed with exit code 1 (use -v to see invocation)
make: *** [Makefile:121: libPoorMans_thatsyou_client_armeabi-v7a.so] Error 1
15:40:32: The process "C:\Users\Kaguro\AppData\Local\Android\Sdk\ndk\23.1.7779620\prebuilt\windows-x86_64\bin\make.exe" exited with code 2.
15:40:33: Error while building/deploying project PoorMans_thatsyou_client (kit: Android Qt 6.4.2 Clang armeabi-v7a)
15:40:33: When executing step "Make"

The opencv and the Qt use the same armeabi-v7a.

Kaguro

Somebody tried to use OpenCV with Qt c++ android with armeabi-v7a? I am very beginner in this kind of project, so I dont know what is the most correct way to use OpenCV with Qt Android. Has anyone tried it and succeeded?

jsulm

@Kaguro Please post whole build log.