need solution for "libopencv not found"

[facebook]

need solution for "libopencv not found"

[sjuxax]

I started getting this too on ArchLinux. It's caused by OpenCV 3.4.1. This release apparently started using C++ namespaces, which cause ffmpeg's configure script to fail the build. ffmpeg is happy again after downgrading to OpenCV 3.4.0.

Described in more depth at opencv/opencv#10963 . This is going to affect a lot of projects that depend on ffmpeg and opencv.

I got it to compile locally installing opencv 2:
git clone --branch 2.4 https://github.com/opencv/opencv.git
mkdir opencv/build && cd opencv/build
cmake -D CMAKE_BUILD_TYPE=Release -D CMAKE_INSTALL_PREFIX=/usr/local ..
make
sudo make install

Then you have to clean/rebuild Transform360 in order to pick up this opencv version before building ffmpeg.

[andreanobile]

it works with opencv 3.4.2, install locally then set PKG_CONFIG_PATH to your local opencv installation.
for example in my case: export PKG_CONFIG_PATH=/home/andrea/opencv3.4.2/lib/pkgconfig:$PKG_CONFIG_PATH

[kcircnc]

Sounds like you have problem with opencv installation, not transform360.
Can you confirm that opencv works in your environment? If not you can probably find help here: https://opencv.org/

[sjuxax]

Incomplete attempt to get the OpenCV filter building as a C++ module here: https://github.com/sjuxax/FFmpeg/tree/cpp_opencv . Note that in the issue referenced above, OpenCV contributors indicate that even if one can successfully build against OpenCV as C (as one can in versions 3.4.0 or earlier), there will probably be substantial issues with such builds.

[sjuxax]

I raised this issue on the ffmpeg-devel mailing list this morning (see http://ffmpeg.org/pipermail/ffmpeg-devel/2018-March/226872.html ). Though it's not settled yet, the consensus seems to be leaning toward dropping support for the OpenCV filter altogether.

I haven't looked into the code to see how heavily Transform360 leans on ffmpeg's OpenCV filter, but it seems like that may be a dependency that will need to be dropped soon, if possible.

[adamjgrant]

I ended up solving this dependency by running this shell script: https://milq.github.io/install-opencv-ubuntu-debian/

Then following the rest of the instructions on the transform360 readme worked like a charm.

[dioptre]

I got sick of how many bad options for building there were so built a fail-safe fork (hopefully) here https://github.com/dioptre/transform360