OpenCV 3.0 with Java cannot open video file, but it woks with camera. Before I was using OpenCV 3.0-beta it was working well in both, but in OpenCV 3.0 which is released on 2015-04-24 doesn't work with video file.
If anyone know about this problem of OpenCV 3, please tell me the reason and how to solve this.
I solved my problem like this: Copy the C:\opencv\build\x64\vc12\bin to the system path and restart the Eclipse.
Hope this help someone that may has this problem with OpenCV 3.0.
Even after adding C:\opencv\build\x64\vc12\bin to SYSTEM path, if you cannot open VideoCapture then you could also try coping opencv_ffmpegXXX_64.dll from opencv/build/java/x64 or from opencv\build\x64\vc14\bin. I don't know why this works but it worked for me after trying:
https://stackoverflow.com/a/29920295/677185 and https://github.com/opencv/opencv/issues/4974
来源：https://stackoverflow.com/questions/29899471/opencv-3-0-videocapture-doesnt-open-video-file-in-java