I'm trying to get VideoCapture working with OpenCV. The video I'm trying to load is in XVID format (checked it with VideoCapture::get(CV_CAP_PROP_FOURCC)). It works fine, but whenever I try to get the video framerate (VideoCapture::get(CV_CAP_PROP_FPS)) I get -nan.
I've used the same video and the same code on another computer (at uni, they have a custom Debian installation) and I can confirm that the framerate info is there (it works fine there). I read somewhere that Ubuntu recently removed ffmpeg from their repositories (I use Linux Mint 17.2), so I installed the ffmpeg package from the ppa:kirillshkrogalev/ffmpeg-next repositories. After that I recompiled OpenCV and installed again, without any change.
I'm using OpenCV 2.4.11 with C++ under Linux Mint 17.2.
Probably XVID is missing on your linux machine which is required by ffmpeg. Try installing XVID as below, it may help you.
cd /opt
wget http://downloads.xvid.org/downloads/xvidcore-1.3.2.tar.gz
tar xzvf xvidcore-1.3.2.tar.gz
cd xvidcore/build/generic
./configure --prefix="$HOME/ffmpeg_build"
make
make install
Related
I´m trying to create named windows and show an image from them using OpenCV in c++. When I try it, I will get an error saying:
The function is not implemented. Rebuild the library with Windows,
GTK+2.x or Cocoa support. If you are on Ubuntu or Debian, install
libgtk2.0-dev and pkg-config, then re-run cmake or configure script in
function 'cvNamedWindow'.
I´m on a raspberry pi using Ubuntu MATE and I didnt have this problem when I was testing on my laptop using Ubuntu. I have checked that all neccessary libraries are installed. So I run cmake again to recompile it, but it still doesn t work.
Is there something different I need to do for Ubuntu MATE? Or is there something else I should try?
I had installed opencv 2.4.9 it worked fine but I was not able to use imgproc header and drawMarker functions so I decided to install opencv 4.1.0 and I ran the cmake and everything but when I check the opencv version using pkg-config --modversion opencv it shows 2.4.9.
by the way, I use ubuntu 14.04 and want to use c++ with opencv.
This is a common mistake. People are installing opencv from the first link and it is generally installing opencv 2.4.9 automatically they do not decide the version while installing.
First thing you need to do is to uninstall opencv. There is a post in this link how to uninstall opencv. The way I prefered:
sudo apt-get autoremove opencv-doc opencv-data libopencv-dev libopencv2.4-java libopencv2.4-jni python-opencv libopencv-core2.4 libopencv-gpu2.4 libopencv-ts2.4 libopencv-photo2.4 libopencv-contrib2.4 libopencv-imgproc2.4 libopencv-superres2.4 libopencv-stitching2.4 libopencv-ocl2.4 libopencv-legacy2.4 libopencv-ml2.4 libopencv-video2.4 libopencv-videostab2.4 libopencv-objdetect2.4 libopencv-calib3d2.4
Then you need to install opencv again. I strongly recommend you this link. Read that article carefully and do the steps. You can decide the opencv version in the line for example version 3.4.3:
git checkout 3.4.3
Ok, just got my first Raspberry pi (3). Went on to install Opencv 3.1.0 using Adrian's guide:
How to Install Opencv 3 on Raspbian Jessie
Installed OpenCV WITH CONTRIB packages as I knew I would need them.
So OpenCV is working fine now. The issue is when I try to use SIFT:
"'module' object has no attribute 'xfeatures2d'"
I did and still do everything by the book, including working on 'cv' environment etc.
I tried checking the site-packages dir of both the python dir and the 'cv' env dir and couldn't find any mention of 'contrib' or 'xfeatures2d'.
Maybe that's the problem? How can I check that the contrib packages were actually compiled with OpenCV?
Thanks in advance.
Because u installed the latest version in OpenCV where they removed sift and surf, I am not sure how they substitute them, anyway u have to install older version of opencv 3.4.2.16 also make sure that opencv contrib of the same version is installed, thats the last working version working with sift/surf not sure if there are special versions for raspberry pi
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've been googling and trying for days now, trying to figure out how to get 32-bit OpenCV working on OS X Lion, but can just find 64-bit version.
So i have the following questions:
OpenCV libraries come in 32-bit or 64-bit arch, is that correct?
How do I get 32-bit OpenCV working on Lion? I've trying the following ways:
- Install OpenCV via MacPorts: nope, MacPorts installs a 64-bit version.BI removed OpenCV and MacPorts.
Install OpenCV 2.4.1 via Homebrew, using the following command:
brew install opencv --build32
but looks like they are 64-bit too. Removed OpenCV and Homebrew.
Install OpenCV 2.4.1 by myself using standard unix makefiles. Nope, they still look like 64-bit.
I've written "they look like 64-bit" because i have to replace OpenC in a Xcode project made under OS X Snow Leopard, targeted for 32-bit Mac, and I always get tons of errors like:
ld: warning: ignoring file /usr/local/Cellar/opencv/2.4.1/lib/libopencv_calib3d.2.4.1.dylib, file was built for unsupported file format which is not the architecture being linked (i386)
so i suppose that the OpenCV stuff is 64-bit. If i force the project to run in 64-bit, it rubs but doesn't work properly and gets stuck.
Is there a standard way to check if my OpenCV libraries are 64-bit or 32-bit?
Where can i get 32-bit OpenCV?
Solved the problem.
Recap: it is possible to have 32-bit OpenCV libraries on 64-bit Mac OSX Lion.
How?
Step 1: Download OpenCV 2.4.0
Step 2: Download and install CMake.
Step 3: Untar the OpenCV package.
Step 4: Make a separate directory inside the OpenCV package for building
mkdir build
cd build
cmake -G "Unix Makefiles" -D CMAKE_OSX_ARCHITECTURES=i386 -D CMAKE_C_FLAGS=-m32 -D CMAKE_CXX_FLAGS=-m32 ..
(this will force the 32-bit compile)
make -j8
sudo make install
Step 5: Enjoy!
For forther reference please visit Mac OS X OpenCV Port Page
Thanks all for putting me on the right track:
#karlphilip: I tried to do as you suggested, but without the make options the compile phase fails, because the architectures are incoherent.
#hamstergene: MacPorts got stuck after the new installation, maybe I have some remains of the older install :( (strange, i followed the official instrusctions to remove it).
#Adrien: That's what I've done, but i had to merge 2 approaches :)
I ve had a hard time configuring OpenCv libraries on a number od different OSs. Turns out that the thing is auto-generating a sample project and then bulding business logic inside it.
See the installation instructions here
The web site of the OpenCV project has been significantly upgraded in the last year.
A new tutorial section is avaiable, i was able to install OpenCV on my 32-bit core Mac OS Lion.
A very cool tutorial is also available at Sadeep's Tech Blog, covering an interesting range of details.
Hope this helps!
Here's something you can try: download OpenCV 2.4 sources and edit the CMakeLists.txt in the root directory. Around line 242 you will see:
# ----------------------------------------------------------------------------
# Path for build/platform -specific headers
# ----------------------------------------------------------------------------
set(OPENCV_CONFIG_FILE_INCLUDE_DIR "${CMAKE_BINARY_DIR}/" CACHE PATH "Where to create the platform-dependant cvconfig.h")
add_definitions(-DHAVE_CVCONFIG_H)
ocv_include_directories(${OPENCV_CONFIG_FILE_INCLUDE_DIR})
below the add_definitions() call, add this one:
add_definitions(-m32)