Copy (ffmpeg) .dll to fix #6

[techtonik]

This attempts to copy all .dll files in build directory,
where should be only ffmpeg .dll

[skvark]

Note that you have to add rule for copying *.dll in setup.py too so that the files are actually copied inside wheels:

https://github.com/skvark/opencv-python/blob/master/setup.py#L33

[techtonik]

Thanks for the pointer.

[techtonik]

File roller keeps crashing on my Fedora, so I am unable to inspect wheel contents.

[techtonik]

Need some sanity test for AppVeyor to ensure that it works (no Windows systems right now there).

Also need to stuff ffmpeg license somewhere..

[skvark]

You can add the license to this file in same manner as the BSD license has been added (with a note that cv2 folder contains the FFmpeg dll): https://github.com/skvark/opencv-python/blob/master/LICENSE-3RD-PARTY.txt

And it could be useful add a unit test for video reading. If there's e.g. some short mp4 public domain clip it could be added to the test folder and then run simple unit test:

import cv2

cap = cv2.videoCapture("filename.mp4")
self.assertTrue(cap.isOpened())

[skvark]

Wheels contain now both dlls, wildcard pattern needs to be modifed.

[techtonik]

I used Chromium test files when I discovered these issues - https://chromium.googlesource.com/chromium/src/+/master/media/test/data/

[techtonik]

Seems like I am out of time to finish this, so feel free to put the final touches here.

[skvark]

I did some testing, the video files open fine if the cv2 folder is in Windows PATH. I'll try to solve this...

[techtonik]

@skvark thanks! I am still unable to get more time for OpenCV.

Now people will have less trouble trying to follow https://www.youtube.com/watch?v=MC00XWdl-ms =)