MacOS Unable to load shared library 'OpenCvSharpExtern' or one of its dependencies.

MacOS Unable to load shared library ‘OpenCvSharpExtern’ or one of its dependencies.

Environment

macOS Big Sur 11.6.1

<PackageReference Include="OpenCvSharp4" Version="4.5.5.20211231" />
<PackageReference Include="OpenCvSharp4.runtime.osx.10.15-x64" Version="4.5.5.20211231" />

What did you do when you faced the problem?

1. Copied libOpenCvSharpExtern.dylib from runtimes/osx-x64/native to bin/debug/net5.0.
2. Installed required dependencies manually:

brew install wget pkg-config mono-libgdiplus gtk+ ffmpeg glog yasm harfbuzz jpeg libpng libtiff openjpeg metis openblas opencore-amr protobuf tbb webp

Output:

Warning: wget 1.21.2 is already installed and up-to-date.
To reinstall 1.21.2, run:
  brew reinstall wget
Warning: pkg-config 0.29.2_3 is already installed and up-to-date.
To reinstall 0.29.2_3, run:
  brew reinstall pkg-config
Warning: mono-libgdiplus 6.1 is already installed and up-to-date.
To reinstall 6.1, run:
  brew reinstall mono-libgdiplus
Warning: gtk+ 2.24.33 is already installed and up-to-date.
To reinstall 2.24.33, run:
  brew reinstall gtk+
Warning: ffmpeg 4.4.1_5 is already installed and up-to-date.
To reinstall 4.4.1_5, run:
  brew reinstall ffmpeg
Warning: glog 0.5.0 is already installed and up-to-date.
To reinstall 0.5.0, run:
  brew reinstall glog
Warning: yasm 1.3.0_2 is already installed and up-to-date.
To reinstall 1.3.0_2, run:
  brew reinstall yasm
Warning: harfbuzz 3.2.0 is already installed and up-to-date.
To reinstall 3.2.0, run:
  brew reinstall harfbuzz
Warning: jpeg 9e is already installed and up-to-date.
To reinstall 9e, run:
  brew reinstall jpeg
Warning: libpng 1.6.37 is already installed and up-to-date.
To reinstall 1.6.37, run:
  brew reinstall libpng
Warning: libtiff 4.3.0 is already installed and up-to-date.
To reinstall 4.3.0, run:
  brew reinstall libtiff
Warning: openjpeg 2.4.0 is already installed and up-to-date.
To reinstall 2.4.0, run:
  brew reinstall openjpeg
Warning: metis 5.1.0 is already installed and up-to-date.
To reinstall 5.1.0, run:
  brew reinstall metis
Warning: openblas 0.3.19 is already installed and up-to-date.
To reinstall 0.3.19, run:
  brew reinstall openblas
Warning: opencore-amr 0.1.5 is already installed and up-to-date.
To reinstall 0.1.5, run:
  brew reinstall opencore-amr
Warning: protobuf 3.19.3 is already installed and up-to-date.
To reinstall 3.19.3, run:
  brew reinstall protobuf
Warning: tbb 2021.5.0 is already installed and up-to-date.
To reinstall 2021.5.0, run:
  brew reinstall tbb
Warning: webp 1.2.2 is already installed and up-to-date.
To reinstall 1.2.2, run:
  brew reinstall webp

1. Checked dependencies for libOpenCvSharpExtern.dylib, everything is available.

otool -L libOpenCvSharpExtern.dylib

Output

libOpenCvSharpExtern.dylib:
	@rpath/libOpenCvSharpExtern.dylib (compatibility version 0.0.0, current version 0.0.0)
	/usr/local/opt/freetype/lib/libfreetype.6.dylib (compatibility version 25.0.0, current version 25.1.0)
	/usr/local/opt/harfbuzz/lib/libharfbuzz.0.dylib (compatibility version 30200.0.0, current version 30200.0.0)
	/usr/local/opt/tesseract/lib/libtesseract.4.dylib (compatibility version 5.0.0, current version 5.1.0)
	/usr/lib/libcurl.4.dylib (compatibility version 7.0.0, current version 9.0.0)
	/usr/local/opt/ffmpeg/lib/libavcodec.58.dylib (compatibility version 58.0.0, current version 58.134.100)
	/usr/local/opt/ffmpeg/lib/libavformat.58.dylib (compatibility version 58.0.0, current version 58.76.100)
	/usr/local/opt/ffmpeg/lib/libavutil.56.dylib (compatibility version 56.0.0, current version 56.70.100)
	/usr/local/opt/ffmpeg/lib/libswscale.5.dylib (compatibility version 5.0.0, current version 5.9.100)
	/usr/local/opt/ffmpeg/lib/libavresample.4.dylib (compatibility version 4.0.0, current version 4.0.0)
	/System/Library/Frameworks/Cocoa.framework/Versions/A/Cocoa (compatibility version 1.0.0, current version 23.0.0)
	/System/Library/Frameworks/Accelerate.framework/Versions/A/Accelerate (compatibility version 1.0.0, current version 4.0.0)
	/System/Library/Frameworks/AVFoundation.framework/Versions/A/AVFoundation (compatibility version 1.0.0, current version 2.0.0)
	/System/Library/Frameworks/CoreGraphics.framework/Versions/A/CoreGraphics (compatibility version 64.0.0, current version 1463.2.1)
	/System/Library/Frameworks/CoreMedia.framework/Versions/A/CoreMedia (compatibility version 1.0.0, current version 1.0.0)
	/System/Library/Frameworks/CoreVideo.framework/Versions/A/CoreVideo (compatibility version 1.2.0, current version 1.5.0)
	/System/Library/Frameworks/QuartzCore.framework/Versions/A/QuartzCore (compatibility version 1.2.0, current version 1.11.0)
	/usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 1292.60.1)
	/System/Library/Frameworks/AppKit.framework/Versions/C/AppKit (compatibility version 45.0.0, current version 2022.20.117)
	/System/Library/Frameworks/OpenCL.framework/Versions/A/OpenCL (compatibility version 1.0.0, current version 1.0.0)
	/usr/lib/libc++.1.dylib (compatibility version 1.0.0, current version 904.4.0)
	/System/Library/Frameworks/CoreFoundation.framework/Versions/A/CoreFoundation (compatibility version 150.0.0, current version 1770.255.0)
	/System/Library/Frameworks/Foundation.framework/Versions/C/Foundation (compatibility version 300.0.0, current version 1770.255.0)
	/usr/lib/libobjc.A.dylib (compatibility version 1.0.0, current version 228.0.0)

1. Ensured project is running under 64 bit architecture:

<PropertyGroup Condition=" '$(Configuration)' == 'Debug' ">
    <PlatformTarget>x64</PlatformTarget>
</PropertyGroup>

1. Installed opencv via Homebrew.
2. Looked into other closed issues, did not find solution to my problem.

Example code:

Console.WriteLine(Cv2.GetVersionString());

Output:

System.TypeInitializationException: The type initializer for 'OpenCvSharp.Internal.NativeMethods' threw an exception.
 ---> System.DllNotFoundException: Unable to load shared library 'OpenCvSharpExtern' or one of its dependencies. In order to help diagnose loading problems, consider setting the DYLD_PRINT_LIBRARIES environment variable: dlopen(libOpenCvSharpExtern, 1): image not found
   at OpenCvSharp.Internal.NativeMethods.redirectError(CvErrorCallback errCallback, IntPtr userdata, IntPtr& prevUserdata)
   at OpenCvSharp.Internal.ExceptionHandler.RegisterExceptionCallback()
   at OpenCvSharp.Internal.NativeMethods.LoadLibraries(IEnumerable`1 additionalPaths)
   at OpenCvSharp.Internal.NativeMethods..cctor()
   --- End of inner exception stack trace ---
   at OpenCvSharp.Internal.NativeMethods.core_getVersionString(Byte* buf, Int32 maxLength)
   at OpenCvSharp.Cv2.GetVersionString()

What did you intend to be?

Library works and outputs version correctly.

[liviaerxin]

As @obie73 said, the OpenCvSharp of version 4.5.5.2021.1213 is not compatible with the installed ffmpeg version 5.x.x. It has to install ffmpeg with version 4.x.x.

There is a cue from loading libOpenCvSharpExtern.dylib test.

❯ ./dyld_open_test /Users/siyao/Documents/astri-workspace/ART340/AstriEndoFormat/cli/bin/Debug/net6.0/runtimes/osx-x64/native/libOpenCvSharpExtern.dylib
dlopen(/Users/siyao/Documents/astri-workspace/ART340/AstriEndoFormat/cli/bin/Debug/net6.0/runtimes/osx-x64/native/libOpenCvSharpExtern.dylib, 
1): Library not loaded: /usr/local/opt/ffmpeg/lib/libavcodec.58.dylib
  Referenced from: /Users/siyao/Documents/astri-workspace/ART340/AstriEndoFormat/cli/bin/Debug/net6.0/runtimes/osx-x64/native/libOpenCvSharpExtern.dylib
  Reason: image not found
dlopen sample%          
                                                                                                                                                
❯ ll /usr/local/opt/ffmpeg/lib/
total 85168
-rw-r--r--   1 siyao  admin    11M Jul  6 17:08 libavcodec.59.18.100.dylib
lrwxr-xr-x   1 siyao  admin    26B Apr  4 22:40 libavcodec.59.dylib -> libavcodec.59.18.100.dylib

After brew install ffmpeg@4, it works out. (Remember link such as ln -s /usr/local/Cellar/ffmpeg@4/4.4.2_3/ /usr/local/opt/ffmpeg)

❯ ll /usr/local/Cellar/ffmpeg@4/4.4.2_3/lib
total 84720
-rw-r--r--   1 siyao  admin    11M Jul  6 17:13 libavcodec.58.134.100.dylib
lrwxr-xr-x   1 siyao  admin    27B Apr 15 04:13 libavcodec.58.dylib -> libavcodec.58.134.100.dylib

[reo-1963]

I was getting this problem and one of the errors referred to: could not find /usr/local/opt/tesseract/lib/tesseract.5.dylib I did a homebrew install of tesseract brew install tesseract and now it works. Only working on a AMD64 (x64) Mac and tested on Monterey and building within “Visual Studio for Mac”

<PackageReference Include="OpenCvSharp4" Version="4.7.0.20230115" />
<PackageReference Include="OpenCvSharp4.runtime.osx.10.15-x64" Version="4.6.0.20230105" />
<PackageReference Include="OpenCvSharp4.runtime.win" Version="4.7.0.20230115" />

FYI: https://www.oreilly.com/library/view/building-computer-vision/9781838644673/95de5b35-436b-4668-8ca2-44970a6e2924.xhtml