Build fails on OSX with latest FFMPEG release

[goulash1971]

Hi there - this is more of an FYI / PSA than an issue :)

I have been experiencing a build error on OSX Mojave ...

[ 87%] Building CXX object modules/calib3d/CMakeFiles/opencv_calib3d.dir/src/calibinit.cpp.o
In file included from /Users/stuart/Workspaces/GITHUB/opencv4nodejs/node_modules/opencv-build/opencv/opencv_contrib/modules/text/src/erfilter.cpp:43:
/Users/stuart/Workspaces/GITHUB/opencv4nodejs/node_modules/opencv-build/opencv/opencv_contrib/modules/text/src/precomp.hpp:54:10: fatal error:
      'tesseract/baseapi.h' file not found
#include <tesseract/baseapi.h>
         ^~~~~~~~~~~~~~~~~~~~~

Looking at a bunch of other issues that have been raised and mostly solved, it appears that this is in part due to the presences of tesseract on my machine (see issue #179). Prior to this change the the brew formula for ffmpeg ...

Homebrew/homebrew-core@3e99e5d#diff-8f4deb87ce96b9c5efe97be3288bb406

.. tesseract was not automatically installed and therefore when the auto-build executed the tesseract library was not found etc.

I've checked that the tesseract header files are installed correctly by brew, and these seem to be in the right place (/usr/local/include/tesseract), so I am guessing that there is a problem with the opencv build scripts.

I haven't got time to start debugging all of that so my work around is (horribly) to rollback the ffmpeg install for the time being.

UPDATE

Whilst the build goes through I have 'amused' myself by digging into the CMake files for OpenCV and I think that the problem I am getting is related to this change ...

opencv/opencv_contrib@fdb575d#diff-cad4fd9d74cc81b36a9dc481ed253200

.. it looks like the Tesseract_INCLUDE_DIRS should be set (see https://github.com/opencv/opencv_contrib/blob/3.4/modules/text/cmake/FindTesseract.cmake).

Anyway, there is a 'switch' that can block the inclusion of the tesseract OCR (OPENCV_FIND_TESSERACT) ... just not sure where it could be set ... any ideas @justadudewhohacks

[goulash1971]

UPDATE

Spent a little longer looking at this and, the fix or Tesseract_INCLUDE_DIRS (i.e opencv/opencv_contrib@fdb575d#diff-cad4fd9d74cc81b36a9dc481ed253200) hasn't been included in any of the releases yet (either v3.x or v4.x of opencv_contrib).

The fix was committed to the master branch on 7th January 2019, long after 3.4.3 was released on the 28th August 2018.

Also, I set OPENCV_FIND_TESSERACT=NO using the OPENCV4NODEJS_AUTOBUILD_FLAGS option that was added recently in the hope that it would skip all of the tesseract stuff, but that didn't work.

Debugging the cmake files, and since the CMAKE_CROSSCOMPILING flag defaults to FALSE line #4 in opencv_contrib/modules/text/CMakeLists.txt ...

if(NOT CMAKE_CROSSCOMPILING OR OPENCV_FIND_TESSERACT)

This means that, irrespective of what I set OPENCV_FIND_TESSERACT to it goes and finds tesseract and lep using pkg_check_modules (on my machine) and then, because the commit isn't in the release blows up because Tesseract_INCLUDE_DIR is not set.

I have absolutely no idea whether the NOT CMAKE_CROSSCOMPILING OR OPENCV_FIND_TESSERACT condition is correct, but I rather wish whomever had coded it had added some brackets in there, or perhaps event a comment >>shock<<, to try and give some direction !!.

My naive view is that the build should not go looking for tesseract if the OPENCV_FIND_TESSERACT is any thing other than YES/TRUE/ON etc.

However, I patched setup-opencv.js in npm-opencv-build to merge the missing commit into the 3.4.3 release ...

module.exports = function() {
  const opencvRepo = 'https://github.com/opencv/opencv.git'
  const opencvContribRepo = 'https://github.com/opencv/opencv_contrib.git'
  return getMsbuildIfWin().then(msbuild =>
    exec(getMkDirCmd('opencv'), { cwd: rootDir })
      .then(() => exec(getRmDirCmd('build'), { cwd: opencvRoot }))
      .then(() => exec(getMkDirCmd('build'), { cwd: opencvRoot }))
      .then(() => exec(getRmDirCmd('opencv'), { cwd: opencvRoot }))
      .then(() => exec(getRmDirCmd('opencv_contrib'), { cwd: opencvRoot }))
      // start - modified to include a 'hotfix' for the Tesseract_INCLUDE_DIRS
      .then(() => spawn('git', ['clone', '-b', `${tag}`, '--single-branch', '--depth',  1, '--progress', opencvContribRepo], { cwd: opencvRoot }))
      .then(() => spawn('git', ['remote', 'add', 'master', opencvContribRepo], { cwd: `${opencvRoot}/opencv_contrib` }))
      .then(() => spawn('git', ['fetch', 'master'], { cwd: `${opencvRoot}/opencv_contrib` }))
      .then(() => spawn('git', ['cherry-pick', 'fdb575d'], { cwd: `${opencvRoot}/opencv_contrib` }))
      // end - modified to include a 'hotfix' for the Tesseract_INCLUDE_DIRS
      .then(() => spawn('git', ['clone', '-b', `${tag}`, '--single-branch', '--depth',  1, '--progress', opencvRepo], { cwd: opencvRoot }))
      .then(() => spawn('cmake', getCmakeArgs(isWin() ? getWinCmakeFlags(msbuild.version) : getSharedCmakeFlags()), { cwd: opencvBuild }))
      .then(getRunBuildCmd(isWin() ? msbuild.path : undefined))
      .then(() => exec(getRmDirCmd('opencv'), { cwd: opencvRoot }))
      .then(() => exec(getRmDirCmd('opencv_contrib'), { cwd: opencvRoot }))
  )
}

And gave that a go ...

1. it found tesseract
2. it correctly set the Tesseract_INCLUDE_DIRS
3. it correctly resolved the #include <tesseract/baseline.api>

.. but ...

[ 88%] Building CXX object modules/tracking/CMakeFiles/opencv_tracking.dir/src/trackerMIL.cpp.o
In file included from /Users/stuart/Workspaces/GITHUB/npm-opencv-build/opencv/opencv_contrib/modules/text/src/erfilter.cpp:43:
In file included from /Users/stuart/Workspaces/GITHUB/npm-opencv-build/opencv/opencv_contrib/modules/text/src/precomp.hpp:54:
In file included from /usr/local/Cellar/tesseract/4.0.0/include/tesseract/baseapi.h:27:
In file included from /usr/local/Cellar/tesseract/4.0.0/include/tesseract/apitypes.h:23:
/usr/local/Cellar/tesseract/4.0.0/include/tesseract/publictypes.h:33:1: error: unknown type name 'constexpr'
constexpr int kPointsPerInch = 72;
^

And about another 20 errors - so obviously merely resolving the original problem (i.e. getting the build to find the appropriate header files, libraries etc) isn't going to work.

FYI. I also changed the tag to 3.4 so that the head for the 3.4 branch was the one cloned (which includes the commit) and had the same errors.

As I mentioned in my original post on this issue, my current work around-is to rollback ffmpeg (or unlink tesseract) when doing the build/install but I find that "annoying" and unfortunately I don't have the available time (and skills) to jump into debugging the opencv_contrib build further (obviously it's something do with versions of tesseract, so hopefully someone that needs that code will take a look at some point - I will add an Issue to opencv_contrib).

So what I am going to do is fork opencv and opencv_contrib and then modify the 3.4 branch to change the NOT CMAKE_CROSSCOMPILING OR OPENCV_FIND_TESSERACT to remove the CMAKE_CROSSCOMPILING clause, since all I want to do is avoid using tesseract and then see whether that build works.

I believe that what would be useful for opencv4nodejs is to be able to specify the git repos (including. tag/branch) for opencv and opencv_contrib as environment variables so that the AUTOBUILD can still be used but against specific OpenCv repos.

Obviously this will be useful for my particular situation, but I also think it will be useful for cases where there is a need/desire to have a custom opencv or opencv_contrib build that retains ABI compatibility with the version of opencv and opencv_contrib supported by opencv4nodejs.

So I will fork, change it, and put in a pull request - I completely understand if the @justadudewhohacks and the other maintainers reject it.

As I mentioned at the beginning this was more of an FYI / PSA :)

[clarsen]

@goulash1971 Did workaround in the meantime until your patch lands:

brew uninstall ffmpeg
brew uninstall tesseract
npm install opencv4nodejs

[Xen0phobe]

@clarsen Thanks. Your workaround got things compiling.

[isonic1]

@clarsen Thanks. This was a major PITA for me.

[phlahut]

@clarsen Thanks，it really works

[clarsen]

Thanks to @goulash1971 ! 👍

[igorms-pro]

I installed successfuly but i have this issue : Error: Cannot find module '...node_modules/opencv4nodejs/build/Release/opencv4nodejs' Im getting crazy

when i launched a program with const cv = require('opencv4nodejs');