Java使用OpenCV3.2实现视频读取与播放

Java使用OpenCV3.2实现视频读取与播放

OpenCV从3.x版本开始其JAVA语言的SDK支持视频文件读写，这样就极大的方便了广大Java语言开发者学习与使用OpenCV，通过摄像头或者视频文件读取帧的内容与播放，完成视频内容分析与对象跟踪等各种应用开发任务。可以说OpenCV C++ SDK可以做到绝大多数事情，在OpenCV3.x版本上用Java都可以完成，这样就为很多Java开发者学习OpenCV打开了方便之门。

实现思路

首先用OpenCV相关API读取视频流或者视频文件的每一帧，然后通过Swing JComponent组件实现视频每一帧的更新显示，我模仿了C++的HIGHGUI里面创建窗口与显示图像接口，基于Swing实现了一个视频播放窗口类，把读取到的每一帧都传给它就可以实现连续显示即播放。每帧之间相隔100毫秒，我是通过Java线程Sleep方法实现。

运行效果 - USB摄像头读取每帧

运行效果 - 视频文件读取每帧

代码实现

视频文件读取

package com.gloomyfish.video.demo;

import java.awt.Dimension;
import java.awt.image.BufferedImage;

import org.opencv.core.Core;
import org.opencv.core.Mat;
import org.opencv.videoio.VideoCapture;

public class VideoDemo {

    public static void main(String[] args) {
        System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
        // 打开摄像头或者视频文件
        VideoCapture capture = new VideoCapture();
        //capture.open(0);
        capture.open("D:/vcprojects/images/768x576.avi");
        if(!capture.isOpened()) {
            System.out.println("could not load video data...");
            return;
        }
        int frame_width = (int)capture.get(3);
        int frame_height = (int)capture.get(4);
        ImageGUI gui = new ImageGUI();
        gui.createWin("OpenCV + Java视频读与播放演示", new Dimension(frame_width, frame_height));
        Mat frame = new Mat();
        while(true) {
            boolean have = capture.read(frame);
            Core.flip(frame, frame, 1);// Win上摄像头
            if(!have) break;
            if(!frame.empty()) {
                gui.imshow(conver2Image(frame));
                gui.repaint();
            }
            try {
                Thread.sleep(100);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }

    }

    public static BufferedImage conver2Image(Mat mat) {
        int width = mat.cols();
        int height = mat.rows();
        int dims = mat.channels();
        int[] pixels = new int[width*height];
        byte[] rgbdata = new byte[width*height*dims];
        mat.get(0, 0, rgbdata);
        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);
        int index = 0;
        int r=0, g=0, b=0;
        for(int row=0; row<height; row++) {
            for(int col=0; col<width; col++) {
                if(dims == 3) {
                    index = row*width*dims + col*dims;
                    b = rgbdata[index]&0xff;
                    g = rgbdata[index+1]&0xff;
                    r = rgbdata[index+2]&0xff;
                    pixels[row*width+col] = ((255&0xff)<<24) | ((r&0xff)<<16) | ((g&0xff)<<8) | b&0xff;
                }
                if(dims == 1) {
                    index = row*width + col;
                    b = rgbdata[index]&0xff;
                    pixels[row*width+col] = ((255&0xff)<<24) | ((b&0xff)<<16) | ((b&0xff)<<8) | b&0xff;
                }
            }
        }
        setRGB( image, 0, 0, width, height, pixels);
        return image;
    }

    /**
     * A convenience method for setting ARGB pixels in an image. This tries to avoid the performance
     * penalty of BufferedImage.setRGB unmanaging the image.
     */
    public static void setRGB( BufferedImage image, int x, int y, int width, int height, int[] pixels ) {
        int type = image.getType();
        if ( type == BufferedImage.TYPE_INT_ARGB || type == BufferedImage.TYPE_INT_RGB )
            image.getRaster().setDataElements( x, y, width, height, pixels );
        else
            image.setRGB( x, y, width, height, pixels, 0, width );
    }

}

视频与图像显示窗口类

package com.gloomyfish.video.demo;

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;

import javax.swing.JComponent;
import javax.swing.JDialog;

public class ImageGUI extends JComponent {
    /**
     *
     */
    private static final long serialVersionUID = 1L;
    private BufferedImage image;

    public ImageGUI() {

    }

    @Override
    protected void paintComponent(Graphics g) {
        Graphics2D g2d = (Graphics2D)g;
        if(image == null)  {
            g2d.setPaint(Color.BLACK);
            g2d.fillRect(0, 0, this.getWidth(), this.getHeight());
        } else {
            g2d.drawImage(image, 0, 0, this.getWidth(), this.getHeight(), null);
            System.out.println("show frame...");
        }
    }

    public void createWin(String title) {
        JDialog ui = new JDialog();
        ui.setTitle(title);
        ui.getContentPane().setLayout(new BorderLayout());
        ui.getContentPane().add(this, BorderLayout.CENTER);
        ui.setSize(new Dimension(330, 240));
        ui.setVisible(true);
    }

    public void createWin(String title, Dimension size) {
        JDialog ui = new JDialog();
        ui.setTitle(title);
        ui.getContentPane().setLayout(new BorderLayout());
        ui.getContentPane().add(this, BorderLayout.CENTER);
        ui.setSize(size);
        ui.setVisible(true);
    }

    public void imshow(BufferedImage image) {
        this.image = image;
        this.repaint();
    }

}

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