通过javacv对视频每隔1秒钟截取1张图片

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byte01 2022-12-19 16:54:03 ©著作权

文章标签 javacv ffmpeg java System List 文章分类 虚拟化云计算

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Exception in thread "main" java.lang.NoClassDefFoundError: Could not initialize class org.bytedeco.javacpp.avutil
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:274)
at org.bytedeco.javacpp.Loader.load(Loader.java:385)
at org.bytedeco.javacpp.Loader.load(Loader.java:353)
at org.bytedeco.javacpp.avformat$AVFormatContext.<clinit>(avformat.java:2249)
at org.bytedeco.javacv.FFmpegFrameGrabber.startUnsafe(FFmpegFrameGrabber.java:346)
at org.bytedeco.javacv.FFmpegFrameGrabber.start(FFmpegFrameGrabber.java:340)

http://stackoverflow.com/questions/27733142/could-not-initialize-class-org-bytedeco-javacpp-avutil-on-os-x-along-with-maven

<dependency>
    <groupId>org.bytedeco</groupId>
    <artifactId>javacv</artifactId>
    <version>1.0</version>
</dependency>

FFmpegFrameGrabber g = new FFmpegFrameGrabber("textures/video/anim.mp4");
g.start();

for (int i = 0 ; i < 50 ; i++) {
    ImageIO.write(g.grab().getBufferedImage(), "png", new File("frame-dump/video-frame-" + System.currentTimeMillis() + ".png"));
}

g.stop();

http://stackoverflow.com/questions/15735716/how-can-i-get-a-frame-sample-jpeg-from-a-video-mov

https://github.com/bytedeco/javacv/

JavaCV 随机获取视频中的某些帧的图片

package com.egova.ffmpeg.java;
 
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
 
import javax.imageio.ImageIO;
 
import org.bytedeco.javacv.FFmpegFrameGrabber;
import org.bytedeco.javacv.Frame;
import org.bytedeco.javacv.FrameGrabber.Exception;
import org.bytedeco.javacv.Java2DFrameConverter;
 
public abstract class FrameGrabberKit {
 
    public static void main(String[] args) throws Exception {
        randomGrabberFFmpegImage("F:/CodeSpace/java/ffmpeg_java/resource/月赋情长.mp4", "./target", "月赋情长", 10);
    }
 
     
    public static void randomGrabberFFmpegImage(String filePath, String targerFilePath, String targetFileName, int randomSize)
            throws Exception {
        FFmpegFrameGrabber ff = FFmpegFrameGrabber.createDefault(filePath);
        ff.start();
        int ffLength = ff.getLengthInFrames();
        List<Integer> randomGrab = random(ffLength, randomSize);
        int maxRandomGrab = randomGrab.get(randomGrab.size() - 1);
        Frame f;
        int i = 0;
        while (i < ffLength) {
            f = ff.grabImage();
            if (randomGrab.contains(i)) {
                doExecuteFrame(f, targerFilePath, targetFileName, i);
            }
            if (i >= maxRandomGrab) {
                break;
            }
            i++;
        }
        ff.stop();
    }
 
    public static void doExecuteFrame(Frame f, String targerFilePath, String targetFileName, int index) {
        if (null == f || null == f.image) {
            return;
        }
         
        Java2DFrameConverter converter = new Java2DFrameConverter();
 
        String imageMat = "jpg";
        String FileName = targerFilePath + File.separator + targetFileName + "_" + index + "." + imageMat;
        BufferedImage bi = converter.getBufferedImage(f);
        File output = new File(FileName);
        try {
            ImageIO.write(bi, imageMat, output);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
 
    public static List<Integer> random(int baseNum, int length) {
 
        List<Integer> list = new ArrayList<>(length);
        while (list.size() < length) {
            Integer next = (int) (Math.random() * baseNum);
            if (list.contains(next)) {
                continue;
            }
            list.add(next);
        }
        Collections.sort(list);
        return list;
    }
}

之前每一秒钟截取一张图片，发现有些图片报了“[mpeg4 @ 05938aa0] warning: first frame is no keyframe”这个警告，而且截出的图片都是灰屏，根本没有图片。后来在网上找了很久，终于弄明白了，原来是ffmpeg它有“关键帧”这个说法，所以如果设置的帧的位置不是关键帧的位置的话，就可能截出的图片有问题。后来经过改进，终于搞定了。

public static void main(String[] args) {
    System.out.println(System.getProperty("java.library.path"));
//     System.out.println("Welcome to OpenCV " + Core.VERSION);
//     System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
//     Mat m = Mat.eye(3, 3, CvType.CV_8UC1);
//     System.out.println("m = " + m.dump());

    // 加载本地的OpenCV库，这样就可以用它来调用Java API
    System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
    Test t = new Test();
//    t.test();
//    t.run();
//    t.run2();
    t.run3();
//    System.out.println(t.CmpPic("d:/img/219.jpg"));
  }

public void run3() {
    CvCapture capture = opencv_highgui.cvCreateFileCapture("D:/085402.crf");
    
    //帧率
    int fps = (int) opencv_highgui.cvGetCaptureProperty(capture, opencv_highgui.CV_CAP_PROP_FPS);
    System.out.println("帧率:"+fps);
    
    IplImage frame = null;
    double pos1 = 0;
    
    int rootCount = 0;

    while (true) {
      
      //读取关键帧
      frame = opencv_highgui.cvQueryFrame(capture);
      
      rootCount = fps;
      while(rootCount > 0 ){
        //这一段的目的是跳过每一秒钟的帧数,也就是说fps是帧率(一秒钟有多少帧),在读取一帧后,跳过fps数量的帧就相当于跳过了1秒钟。
        frame = opencv_highgui.cvQueryFrame(capture);
        rootCount--;
      }

      //获取当前帧的位置
      pos1 = opencv_highgui.cvGetCaptureProperty(capture,opencv_highgui.CV_CAP_PROP_POS_FRAMES);
      System.out.println(pos1);

      if (null == frame)
        break;
      
      opencv_highgui.cvSaveImage("d:/img/" + pos1 + ".jpg",frame);
      
    }

    opencv_highgui.cvReleaseCapture(capture);
  }