OpenCV 2.4 VideoCapture not working on Windows

Question

I'm using Python bindings to OpenCV 2.4 installed with following instructions.

My problem is similar to this one, but I need Windows machine solution.

Problem: when I try to use

cap = cv2.VideoCapture(0) print cap.grab() 

it works fine, but the following code

cap = cv2.VideoCapture(filename) print cap.grab() 

always return False.

Path to the file is correct, absolute and has no spaces.

I tried on two machines with Windows XP and Windows 7 with similar results. On Linux (Ubuntu) it works fine for me.

Answer 1

Add C:\OpenCV\3rdparty\ffmpeg\ to the Windows PATH environment variable or copy opencv_ffmpeg.dll from that directory to C:\Python27\ or to a directory that is in the PATH. Alternatively, use the OpenCV binaries from http://www.lfd.uci.edu/~gohlke/pythonlibs/#opencv.

Renaming the opencv_ffmpeg.dll file may also be necessary.

For OpenCV version X.Y.Z
opencv_ffmpeg.dll ==> opencv_ffmpegXYZ.dll

For 64-bit OpenCV version X.Y.Z
opencv_ffmpeg.dll ==> opencv_ffmpegXYZ_64.dll

Answer 2

Copying opencv_ffmpeg.dll wasn't enough for me - I had to rename it to opencv_ffmpeg246.dll, when I used OpenCV 2.4.6 with Python 2.7.5