Cannot open ".mp4" video files using OpenCV 2.4.3, Python 2.7 in Windows 7 machine


I am currently working on a project that involves reading mp4 video files. The problem I encountered is that it using Python 2.7 (32 bit), OpenCV 2.4.3 (cv2.pyd) in a Windows 7 machine.

The code snippet is as follows:

        video = cv2.VideoCapture("video.mp4")
        print "Could not open video file"
print video.grab()

"video.grab()" always returns false: meaning it doesn't read the file "video.mp4" But when we try this:

        video = cv2.VideoCapture("video.avi")
        print "Could not open video file"
print video.grab()

"video.grab()" returns true: meaning it is able to read ".avi" files.

Another is we have tried this same snippet on Linux and Mac and it seems to work fine, meaning it is able to read both mp4 files and avi files.

This problem is similar to this problem and this problem. Both still don't have a clear and workable answer.

I would appreciate any help or workaround aside from just using Linux or Mac for programming this as I need this to work on all three systems.

12/12/2012 6:54:50 AM

I have had the same issue before, solved by this step:

Check your OpenCV python version

>>> from cv2 import __version__
>>> __version__

Then Copy your opencv_ffmpeg.dll to C:\Python27\ and rename it to relevant your OpenCV Python Version. In my case I had to rename it to opencv_ffmpeg240.dll.

Update: On Windows, you can find the opencv_ffmpeg DLL inside of the build folder of your OpenCV installation. For example: C:\dev\opencv\build\x86\vc12\bin

Then, just copy and paste the opencv_ffmpeg<version>.dll file into the root folder of your Python installation.

9/9/2017 8:39:39 PM

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