OpenCVSharp: Unable to load DLL 'OpenCvSharpExtern'

Question

I have installed the latest OpenCVSharp 2 (2.4.10.201...) with the NuGet manager in my project. Everything concerning OpenCVSharp.CvMat is working OK (loading, manipulation etc) so I am sure the installation is correct.

However I cannot use OpenCVSharp.CPlusPlus at all! The problem is that it doesn't load OpenCvSharpExtern.dll.

Error shown from try-catch block:

try
{
    Mat mat = new Mat();
} catch (Exception err)
{
    Console.WriteLine( err );
}

System.TypeInitializationException: The type initializer for 'OpenCvSharp.CPlusPlus.Mat' threw an exception. ---> System.DllNotFoundException: Unable to load DLL 'OpenCvSharpExtern': The specified module could not be found. (Exception from HRESULT: 0x8007007E)
   at OpenCvSharp.CPlusPlus.NativeMethods.core_Mat_sizeof()
   at OpenCvSharp.CPlusPlus.Mat..cctor()
   --- End of inner exception stack trace ---
   at OpenCvSharp.CPlusPlus.Mat..ctor()
   at MainClass.Main() in C:\Users\kotsias\Documents\Visual Studio 2015\Projects\MyCVSharp\ConsoleApplication1\Test.cs:line 14

The OpenCvSharpExtern.dll IS deployed alongside my .exe inside the following subfolders:

..\dll\x86

&

..\dll\x64

If I manually copy the x64 .dll in the same folder as my .exe, I still get the same error above. If I copy the x86 .dll, I get a different error:

System.TypeInitializationException: The type initializer for 'OpenCvSharp.CPlusPlus.Mat' threw an exception. ---> System.BadImageFormatException: An attempt was made to load a program with an incorrect format. (Exception from HRESULT: 0x8007000B)
   at OpenCvSharp.CPlusPlus.NativeMethods.core_Mat_sizeof()
   at OpenCvSharp.CPlusPlus.Mat..cctor()
   --- End of inner exception stack trace ---
   at OpenCvSharp.CPlusPlus.Mat..ctor()
   at MainClass.Main() in C:\Users\kotsias\Documents\Visual Studio 2015\Projects\MyCVSharp\ConsoleApplication1\Test.cs:line 14

score 20 · Answer 1 · answered Oct 22 '20 at 10:29

20

It is not enough installing the "OpencvSharp{version} nuget" package. You also have to install the "OpencvSharp{version}.runtime.{operating_system}" package.

For example, in my case I had to install the following Nuget pacages:

OpencvSharp4
OpencvSharp4.runtime.win

answered Oct 22 '20 at 10:29

Pablo Iñigo Blasco

544
5
8

Installing `OpenCVSharp4.runtime.*` solved the problem for me. – taylorswiftfan Nov 20 '22 at 20:11
That solved my problem. Thanks – Zimo Jul 26 '23 at 15:23

score 4 · Answer 2 · answered Jun 17 '21 at 14:41

4

Another issue that some may be hitting:

OpenCvSharpExtern.dll requires mfplat.dll that is part of the Media Feature Pack. Windows 'N' editions do not include this by default.

It can be installed from Apps and Features->Optional features->Add a feature.

answered Jun 17 '21 at 14:41

GazTheDestroyer

20,722
9
70
103

1

Also, on Server Core I fixed this with `Install-WindowsFeature -Name Server-Media-Foundation` – Peter Wishart Jun 29 '21 at 20:50
2

This answer probably saved a few hours of my life. – Kaan C. Fidan Oct 12 '21 at 15:06

score 1 · Accepted Answer · edited Jun 20 '20 at 09:12

1

Probably you don't have correct version of Visual C++ Redistributable package installed.

OpenCvSharp 2.4.10 uses Visual C++ 2013 Redistributable Package. However, OpenCvSharp 2.4.10 is deprecated and author recommends to use OpenCvSharp 3.2:

#OpenCvSharp 2.4.10 Cross platform wrapper of OpenCV 2.4.10 for .NET Framework.

This project is deprecated. The latest release is available in OpenCvSharp.

For more information check:

edited Jun 20 '20 at 09:12

Community

1
1

answered May 22 '17 at 10:56

Leonid Vasilev

11,910
4
36
50

I need to use 3.5 framework, so I'm probably stuck with the older version. I tried the latest one but it wouldn't work with anything less than 4.0. – Bill Kotsias May 22 '17 at 11:29
1

Project README.md states that .NET Framework 2.0 and newer is supported. I created corresponding [issue](https://github.com/shimat/opencvsharp/issues/352) on GitHub. – Leonid Vasilev May 22 '17 at 14:27

score 1 · Answer 4 · edited Oct 03 '19 at 12:43

1

Use this code on Package manager :

Install-Package OpenCvSharp4.Windows -Version 4.0.0.20190108

edited Oct 03 '19 at 12:43

Dharman

30,962
25
85
135

answered Oct 03 '19 at 12:39

hossein andarkhora

740
10
23

score 1 · Answer 5 · answered Oct 03 '22 at 08:03

I was having this problem in production (After Creating the Setup File and Installing it). I've solved it by doing the following steps

Installed the OpenCVSharp Through NuGet Packages
Setting the Platform Target to X64 in Project Properties
Creating the Setup File with the same Platform
Manually Copying the "packages\OpenCvSharp4.runtime.win.4.5.3.20210817\runtimes\win-x64\native\OpenCvSharpExtern.dll" file into the installation directory.

OpenCVSharp: Unable to load DLL 'OpenCvSharpExtern'

5 Answers5

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