DLL load fails on Anaconda/Windows install (python3.dll) #36
Description
After doing a simple pip install opencv-python or pip install opencv-contrib-python and trying to import the library, I ran into this issue:
λ python Python 3.5.2 |Anaconda 4.2.0 (64-bit)| (default, Jul 5 2016, 11:41:13) [MSC v.1900 64 bit (AMD64)] on win32 Type "help", "copyright", "credits" or "license" for more information. >>> import cv2 Traceback (most recent call last): File "<stdin>", line 1, in <module> File "C:\Anaconda3\lib\site-packages\cv2\__init__.py", line 7, in <module> from . import cv2 ImportError: DLL load failed: The specified module could not be found. The readme suggests installing the Visual C++ Redistributable for Visual Studio 2015
but I already had it installed (actually had Visual Studio itself installed as well).
Checking the dependencies of the pyd binary in this package (using dumpbin which comes with Visual Studio):
λ dumpbin.exe C:\Anaconda3\Lib\site-packages\cv2\cv2.cp35-win_amd64.pyd /IMPORTS | grep dll python3.dll python35.dll MSVFW32.dll AVIFIL32.dll AVICAP32.dll KERNEL32.dll USER32.dll GDI32.dll ole32.dll OLEAUT32.dll COMDLG32.dll ADVAPI32.dll After checking if these were in the PATH I was surprised to find that python3.dll was the only one that wasn't!
Although python3.dll comes with the standard CPython install, it's not packaged with Anaconda for some reason. ContinuumIO/anaconda-issues#1394 references this and it seems like it's just not supported(?).
As a workaround suggested in that thread, I solved this by just copying python3.dll from the official CPython 3.5.2 binaries (specifically from the Windows x86-64 embeddable zip file) into C:\Anaconda3, although I imagine it would work being anywhere in your PATH.
I thought I'd share this bit of troubleshooting since Anaconda is a popular distribution among academics and so is OpenCV, so I figure I might not be the only one running into this issue. Maybe a note in the readme might help others until Anaconda resolves this?
Alternatively, the menpo/opencv3 Anaconda package would also work but I don't think it supports ffmpeg nor opencv-contrib.
For reference, I'm running on Python 3.5.2 which came with Anaconda 4.2.0 (official installer), although conda info reports a slightly newer version:
λ conda info Current conda install: platform : win-64 conda version : 4.3.16 conda is private : False conda-env version : 4.3.16 conda-build version : 2.0.2 python version : 3.5.2.final.0 requests version : 2.12.4 root environment : C:\Anaconda3 (writable) default environment : C:\Anaconda3 envs directories : C:\Anaconda3\envs C:\Users\Talmo\AppData\Local\conda\conda\envs C:\Users\Talmo\.conda\envs package cache : C:\Anaconda3\pkgs C:\Users\Talmo\AppData\Local\conda\conda\pkgs channel URLs : https://repo.continuum.io/pkgs/free/win-64 https://repo.continuum.io/pkgs/free/noarch https://repo.continuum.io/pkgs/r/win-64 https://repo.continuum.io/pkgs/r/noarch https://repo.continuum.io/pkgs/pro/win-64 https://repo.continuum.io/pkgs/pro/noarch https://repo.continuum.io/pkgs/msys2/win-64 https://repo.continuum.io/pkgs/msys2/noarch config file : None offline mode : False user-agent : conda/4.3.16 requests/2.12.4 CPython/3.5.2 Windows/10 Windows/10.0.15063 Cheers and thanks for all the work you put into this repo!