I am trying to install the boost library on windows 10, the first few steps are working:
Downloading the library
Unzipping
Bootstrapping
But then when trying to run b2.exe or bjam.exe there is nothing happening (except high CPU load), but no console output whatsoever, not even an error.
I can't find any explanation or help on the internet, maybe some of you got an idea
Since you've mentioned you're working on Windows, maybe Visual Studio is appropriate for your choice. In such case, you can use vcpkg tool to install boost. Check this link.
Once the tool is installed, it's really easy to install various libraries and they will automatically be detected in your Visual Studio projects. To install boost simply run vcpkg install boost:x64-windows.
I installed OpenCV 2.4.13 after installing the required dependencies and I'm running it with Qt Creator 5.7 for programming in C++. Following some tutorials I managed to load still images, process them and so on. But when I try to use the cv::VideoCapture, for example:
cv::VideoCapture cap;
cap.open("<File location/file name>");
or:
cv::VideoCapture("<File location/file name");
cap.isOpened() always return false. Even if I try to ignore this and go further with Mat, read, imshow and so on, the program crashes. I've already tried everything about loading the file: giving a std::string as argument, giving a *char, putting the video file on easier locations, in the project directory and nothing works. I tried with two different .mp4, with a .mov and with the cube4.avi file given in the "samples" folder (from openCV examples). All these files are perfectly played by my VLC. I've already tried in Qt with a QtWidgets project and with a plainCpp project. It never works. After searching about it, I've seen that this bug is very recurrent, but I've just found solutions for Windows, regarding on adding a .dll file to the project. But what should I do on Ubuntu, since Linux uses no dlls?
I figured out how to solve this and I'm here to share with everyone who encounter similar problems. First of all, my FFmpeg installation was for any unknown reason ignored on the OpenCV compilation. Since FFmpeg is needed to read and write videos, OpenCV wasn't able to do these jobs and displayed no error or warning messages about that. Anyway I decided to try everything again from the beginning. Keep in mind: if you just reinstall FFmpeg, it's not going to solve your problems; after that you have to do cmake, compile and install OpenCV again. I downloaded the most recent version of FFmpeg from the repository, compiled and installed it again. I tried to compile OpenCV again, but it was always stuck at about 15% when processing a FFmpeg (Libav) .h file with the message:
<file_name.h> can not be used when making a shared object; recompile with -fPIC
So I searched for it and with some effort I found out that it was necessary to compile the FFmpeg with the following configure line before doing the make:
.\configure --enable-pic --enable-shared
Some ffmpeg installation tutorials include even more commands after "configure". Then I compiled and reinstalled FFmpeg and compiled and reinstalled OpenCV. After that, I was able to load videos (the cap.isOpened() was no longer false), but nonetheless I was getting the following error for any video and they weren't being read:
Assertion desc failed at libswscale/swscale_internal.h:674
The way I found to solve this was downloading the newest stable FFmpeg version instead of the newest on, compiling it again, compiling OpenCV again and then it was successful! Now I can both load and write video files (I haven't tested it with multiple codecs yet). I wonder why they don't launch pre-compiled versions of OpenCV with everything so that we don't need to deal with all these stuffs...
Summarizing everything:
Download the last stable release of FFmpeg. If it doesn't work, try an older one. (I'm using the 2.8.6, the last stable right now).
Unpack it, open the terminal from the ffmpeg folder, compile and install it typing:
.\configure --enable-pic --enable-shared
make
sudo make install
Download OpenCV (if you haven't done it yet), unpack and install it following the official linux installation tutorial:
http://docs.opencv.org/2.4/doc/tutorials/introduction/linux_install/linux_install.html#linux-installation
I solve the problem by install "opencv3.2.0-dev" instead "opencv3.2.0";
pip install opencv-python is not enough to install OPENCV.
I'm using Qt Creator 5.2 and want to integrate libVLC in my own project. So I downloaded the source of libVLC (for Qt) and also the VLC player itself. I think that I have to build the libVLC source to transform into a libary. But I don't know how to do this. I see that there's a CMakeLists.txt, but as far as I know I can not use CMake to build pro file for QT Creator, but only a sln file for Microsoft VS (which I don't use). Can anybody tell me how to build libVLC?
Thank you
Qt Creator has support for CMake projects
You may build the library using CMake itself
If you're on Linux, then your distribution likely has libvlc and its development headers built and packaged, just search for it in a software center or command-line meta-package manager like apt or yum. If you're on Windows, bad luck :) , you have to build it yourself from sources :)
I would like to create a gui application with Qt, using opencv on Windows XP. I used both Qt and opencv before, but never together. Long story short, I'm unable to get opencv work with Qt.
As on all the forums I searched there are just little pieces of information scattered around, usually with no answer, I summarize here all the steps I've taken.
Downloaded the Qt SDK (4.6.3) for Windows, and used it for some time, successfully.
Downloaded the opencv 2.3.1 megapack for Windows, complete with binaries. I managed to compile my Qt project including opencv successfully, but any opencv function call resulted in a crash. I read on some forums that the binaries in the Windows megapack don't support Qt, and I have to build opencv myself
I downloaded the latest version of CMake (2.8).
I downloaded the source of opencv from here: http://code.opencv.org/svn/opencv/branches/2.3/
I downloaded the source for the version of Qt I had (4.6.3)
I found my old version of visual Studio 2005
I created a VS2005 project with CMake, checking the support for Qt. (WITH_QT checked)
I built opencv in VS2005. It created most of the libraries, but not all. Highgui was among the failed ones. The problem: Qt\4.6.3\src\corelib\global\qconfig.h was not found. There was no qconfig.h at all in the source I downloaded! I found some templates qconfig-large.h, qconfig-small.h etc., so I renamed one of them to qconfig.h. Now I got a screen full of linker errors.
I downloaded the latest Qt source instead (4.8.1). Now there is a source file qbenchmark.h that includes QtTest/qbenchmarkmetric.h which cannot be found.
I gave up, and tried MinGW.
I downloaded the latest MinGW (2011.11.18)
I set CMake to generate a MinGW makefile, but I got the following error:
.
CMake Error at C:/Program Files/CMake 2.8/share/cmake-2.8/Modules/Platform/Windows-g++.cmake:1 (INCLUDE):
include could not find load file:
C:/Program Files/CMake 2.8/share/cmake-2.8/Modules/Platform/Windows-gcc.cmake
Call Stack (most recent call first):
C:/Program Files/CMake 2.8/share/cmake-2.8/Modules/CMakeCXXInformation.cmake:59 (INCLUDE)
True, there is a Windows-g++.cmake file in the Modules/Platform directory, but it references Windows-gcc.cmake which does not exist!
Is there anyone who managed to build opencv with Qt support on Windows, and if yes, how?
Edit:
The problem is definitely with the Qt source. I managed to generate a MinGW makefile, and the build went all OK until it stopped in src/testlib/qtestsystem.h because there was an include for QtCore/qelapsedtimer.h which file is in a completely different directory! Does Qt release incomplete sources, or did I do something wrong?
Edit2
My torment continues. I cleaned everything and started anew. This time without even trying Visual Studio.
I downloaded the latest Qt libs with source (4.8.1)
I downloaded the latest MinGW (2011.11.18)
With CMake I successfully created a Makefile, and built it with MinGW. I got some shiny new libs (libopencv_core231, etv.). I was very happy, but how wrong I was to celebrate that soon!!
I downloaded the latest Qt SDK (strangely, it was 4.8.0, so I set Qt Creator to use the 4.8.1) and created a test program without opencv to see if it works. It worked!
I tried using opencv, just reading and displaying an image. It didn't work. exited with code -1073741511
I tried running the .exe directly, outside of Qt Creator. It complained of a missing libstdc++-6.dll
I did a search for it, and found on in my MinGW install (c:\mingw\bin, 958 KB), and one in my Qt install (c:\qt\mingw\bin, 793 KB) - this mingw came bundled with Qt.
I tried both, by copying them in the same folder where my .exe is, but neither worked. I got "The procedure entry point _ZNSt9exceptionD2Ev could not be located in the dynamic link library libstdc++-6.dll." with both. This was in debug, so I tried release, and I got a similar error, with some other entry point not found.
I searched the forums, and I found suggestions that I should link libstdc++ statically. I inserted -static-libgcc -static-libstdc++ at the lines QMAKE_LFLAGS = and QMAKE_LFLAGS_DEBUG = in the file c:\Qt\mkspecs\win32-g++\qmake.conf. This had no effect at all, even after restarting Qt Creator and rebuilding. If I don't copy the libstdc++-6.dll, it still requires it.
Of course, my simple test program without opencv runs from the exe without needing any libstdc++-6.dll, so that means my opencv build is responsible? I wanted to build opencv anew, but I cannot find any CMake settings referring to libstdc++ !
It might be a clue:
When using one of the libstdc++-6.dll files, the error about a missing entrypoint mentions QtGui4.dll. I have a debug build, so it should be QtGui*d*4.dll, shouldn't it? Are there different libstdc++s for debug and release? Either way, I tried to build release, but it didn't work either, same error
Is there no single person on this planet who tried using Qt with QtCreator and opencv 2.3 together on Windows xp, and succeeded? From searching all the forums and Qt archives, I could not find anyone. I'm ready to do the development in Linux, but I'll need a Windows release sooner or later anyway.
I'm trying to resist the temptation of the dark side, which whispers into my ears to forget Qt, MinGW, g++, opencv and try to hack together something in Visual Basic. Oh, the horrors!
Just FYI, I went basically through the same nightmare of combining Qt and OpenCV. This was my experience:
I downloaded the Qt SDK 4.7.4 with Qt Creator 2.4.1 and installed it, no problem.
I downloaded and installed OpenCV 2.4.2 and not knowing that it already came with MinGW...
I downloaded the MinGW compiler which of course had a different version than the one which came already with Qt
This completely messed up my CMake, even when I explicitly told CMake to use the Qt gcc.exe and g++.exe it also used some stuff from my freshly installed MinGW. Probably because I eagerly added every directory to my PATH variable. What a fool I was!
CMake was not able to generate any useful files, so I gave up and installed the OpenCV superpack, hoping this would make things easier.
6.I spent hours wondering, why Qt and OpenCV from the superpack didnt work properly together. I never quite understood. I had the same errors that other users describe here, like console programs crashing as soon as some OpenCV was included. The strange thing is, that I could start the executable manually from FileExplorer (I added all .dlls you could think of to the project folder: opencv_core242.dll, opencv_highgui242.dll, QtCore4.dll, QtGui4.dll and so on...) BUT I could not launch my little test program from within the Qt Creator environment.
I analysed if there was a problem with my DLLs using depends.exe and found out that even though I configured everything to be in DEBUG using the MinGW compiler, my program still tried to use QtCore4.dll and not QtCore4d.dll... So my best guess was, that it was mixing debug and release version.
I gave up using the superpack and again tried to use CMAKE first and then build OpenCV using the Qt MinGW version AND making sure to setup everything for Debug mode and enable the QT option. But no luck with that so far
I stopped using MinGW and switched over to MSVC2010, which works better. However I am still not able to debug the program since the MSVC2010 debugger engine seems to be missing. I dont really know how to manually add this but I am still working on it
So what I can definitely tell is that using Qt and OpenCV for somebody who has little experience is far from trivial!
You should build OpenCV from source, as you already did, it is no hassle. Note that recent versions of OpenCV can be built with and w/o Qt. Highgui optionally uses Qt! It is your choice if you build with or without Qt.
I used Qt libraries together with OpenCV for long time now. I never went for the SDK, instead I used the libs which are built for corresponding VS version. See here: http://qt.nokia.com/downloads/downloads#qt-lib
You can have it for VS2008 and VS2010, but earlier versions are also available built for VS2005. Old versions of Visual Studio suck so hard, why use them anyway.
Then I never had problems pulling it together in a CMake project. It goes along the lines of:
find_package(OpenCV)
find_package(Qt4 ${VOLE_MINIMUM_QT_VERSION} COMPONENTS QtCore QtGui)
find_package(Qt4 ${VOLE_MINIMUM_QT_VERSION} COMPONENTS QtOpenGL)
...
qt4_wrap_cpp(moc_sources ${vole_module_moc_sources})
qt4_wrap_ui(uic_sources ${vole_module_ui_sources})
qt4_add_resources(rcc_sources ${vole_module_rcc_sources})
You know, the usual stuff.
Five man weeks later you may probably get it run under Windows, while under GNU/Linux it is three commands in the shell.
You might have an easier time configuring Qt Creator with OpenCV. This post shows how to achieve that, step-by-step! It displays several screenshots to aid in the process too.
I am trying to set up a development environment to play around with developing Qt apps for Symbian devices. I have succesfully set up the environment and am able to create simple apps such as HelloWorld and get them to run on my device. I would now like to try using the QtMobility package, but I am struggling to get it to work in QtCreator.
I got some sample code for using the camera (initially I only had QtMobility 1.0.2, but I have now downloaded the 1.1.0 technology preview version). I followed the instructions in the help file to install it, here is what I did:
Extracted the zip file to C:\QtMobility
Opened a Qt Command prompt and ran configure (in the QtMobility directory)
Ran mingw32-make
Ran mingw32-make install
Finally I updated my PATH variable to include C:\QtMobility\lib
I went back to QtCreator (restarted it) and looked at the cpp file that first calls the macro QTM_USE_NAMESPACE but it is still underlined in red, because it can't find the qmobilityglobal.h file.
Does anyone know if I have missed anything out during the installation that will tell the QtCreator where to find the QtMobility header files?
mingw32-make suggests you're building for win32-mingw target environment. To work with Symbian SDKs, you should be building for e.g. symbian-abld instead. The configure.bat script will auto-detect the target you are building for. Just make sure that QT_PATH environment variable points to a location where you have a Symbian build of the Qt toolchain.
(Also note that make install is unnecessary with symbian-abld - the build step already puts everything in place in Symbian SDK directories.)