opencv: VideoCapture cannot open video file in Java

You are missing the loading ffmpeg dll. If use 64 add opencv_ffmpeg300_64.dll. If you use 32 add opencv_ffmpeg300.dll. Add this the your code.

System.loadLibrary("opencv_ffmpeg300_64");

System.loadLibrary is not required. Just put opencv_ffmpeg*.dll file(s) near opencv_java*.dll or update PATH environment variable which should point to opencv_ffmpeg*.dll

Using OpenCV 3.0 on windows:

        Mat matOrig = new Mat();
        VideoCapture capture = new VideoCapture("resources/Hummingbird.MP4");
        if( capture.isOpened()){
            while (true){  
                capture.read(matOrig);  
                // get some meta data about frame.              
                double fps = capture.get(Videoio.CAP_PROP_FPS);
                double frameCount = capture.get(Videoio.CAP_PROP_FRAME_COUNT);
                double h = capture.get(Videoio.CAP_PROP_FRAME_HEIGHT);
                double w = capture.get(Videoio.CAP_PROP_FRAME_WIDTH);
                double posFrames = capture.get(Videoio.CAP_PROP_POS_FRAMES);
                double posMsec = capture.get(Videoio.CAP_PROP_POS_MSEC);
                double speed = capture.get(Videoio.CAP_PROP_SPEED);
                if( !matOrig.empty() ) {
                    // do stuff
                }
            }
        }

I have same issue on Ubuntu. I’ve tried to compile ffmpeg from source as shared lib. It creates some libav*.so, but OpenCV Java code still cannot open the mp4/avi file with no errror or warning. What should I do?