How to capture and record video from webcam using JavaCV

Question

I'm new to JavaCV and I have difficult time finding good tutorials about different issues on the topics that I'm interested in. I've succeed to implement some sort of real time video streaming from my webcam but the problem is that I use this code snippet which I found on the net :

@Override
    public void run() {

        FrameGrabber grabber = new VideoInputFrameGrabber(0); // 1 for next
                                                                // camera
        int i = 0;
        try {
            grabber.start();
            IplImage img;
            while (true) {
                img = grabber.grab();
                if (img != null) {
                    cvFlip(img, img, 1);// l-r = 90_degrees_steps_anti_clockwise
                    cvSaveImage((i++) + "-aa.jpg", img);
                    // show image on window
                    canvas.showImage(img);
                }

that results in multiple jpg files.

What I really want to do is capture my webcam input and along with showing it I want to save it in a proper video file. I find out about FFmpegFrameRecorder but don't know how to implement it. Also I've been wondering what are the different options for the format of the video file, because flv maybe would be more useful for me.

Answer 1

It's been quite a journey. Still a few things that I'm not sure what's the meaning behind them, but here is a working example for capturing and recording video from a webcam using JavaCV:

import com.googlecode.javacv.CanvasFrame;
import com.googlecode.javacv.FFmpegFrameRecorder;
import com.googlecode.javacv.OpenCVFrameGrabber;
import com.googlecode.javacv.cpp.avutil;
import com.googlecode.javacv.cpp.opencv_core.IplImage;

public class CameraTest {

    public static final String FILENAME = "output.mp4";

    public static void main(String[] args) throws Exception {
        OpenCVFrameGrabber grabber = new OpenCVFrameGrabber(0);
        grabber.start();
        IplImage grabbedImage = grabber.grab();

        CanvasFrame canvasFrame = new CanvasFrame("Cam");
        canvasFrame.setCanvasSize(grabbedImage.width(), grabbedImage.height());

        System.out.println("framerate = " + grabber.getFrameRate());
        grabber.setFrameRate(grabber.getFrameRate());
        FFmpegFrameRecorder recorder = new FFmpegFrameRecorder(FILENAME,  grabber.getImageWidth(),grabber.getImageHeight());

        recorder.setVideoCodec(13);
        recorder.setFormat("mp4");
        recorder.setPixelFormat(avutil.PIX_FMT_YUV420P);
        recorder.setFrameRate(30);
        recorder.setVideoBitrate(10 * 1024 * 1024);

        recorder.start();
        while (canvasFrame.isVisible() && (grabbedImage = grabber.grab()) != null) {
            canvasFrame.showImage(grabbedImage);
            recorder.record(grabbedImage);
        }
        recorder.stop();
        grabber.stop();
        canvasFrame.dispose();
    }
}

It was somewhat hard for me to make this work so in addition to those that may have the same issue, if you follow the official guide about how to setup JavaCV on Windows 7/64bit and want to capture video using the code above you should create a new directory in C:\ : C:\ffmpeg and extract the files from the ffmped release that you've been told to download in the official guide. Then you should add C:\ffmpeg\bin to your Enviorment variable PATH and that's all. About this step all credits go to karlphillip

and his post here