1.准备

      有可连接的摄像头，例如大华、海康

   ffmpeg下载：https://blog.csdn.net/qq_16855077/article/details/89839708

   例如下面rtsp各个品牌的url不同，这里就不过多的说明

   rtsp://admin:[email protected]:554/Streaming/Channels/101?transportmode=unicast

 

 2.截图

package com.qihui.qxj.services.system;

import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;

import org.junit.Test;

public class Test1 {
	@Test
	public void test1() {
		List commend = new ArrayList();
		commend.add("c:/bin/ffmpeg.exe");
		commend.add("-i");
		commend.add("rtsp://admin:[email protected]:554/Streaming/Channels/101?transportmode=unicast");
		commend.add("-s");
		commend.add("4096*1800");
		commend.add("-b");
		commend.add("4M");
		commend.add("-y");
		commend.add("-f");
		commend.add("image2");
		commend.add("-an");
		commend.add("-loglevel");
		commend.add("8");
	
		commend.add("d:/project/direct/40/a1.jpg");
		Process p = null;
		try {
			ProcessBuilder builder = new ProcessBuilder(commend);
			builder.command(commend);
			p = builder.start();
			p.getOutputStream().close();
			doWaitFor(p);
			p.destroy();
			System.out.println(1122);
		} catch (Exception e) {
			PrintCatchErrorMsg.Print(e, "Part", "getRSTPPicture.catch", "Exception");
			p.destroy();
		}
	}
	
   
   public static int doWaitFor(Process p) {
	      InputStream in = null;
	      InputStream err = null;
	      int exitValue = -1;

	      try {
	         in = p.getInputStream();
	         err = p.getErrorStream();
	         boolean finished = false;

	         while(!finished) {
	            try {
	               Character c;
	               while(in.available() > 0) {
	                  c = new Character((char)in.read());
	                  System.out.print(c);
	               }

	               while(err.available() > 0) {
	                  c = new Character((char)err.read());
	                  System.out.print(c);
	               }

	               exitValue = p.exitValue();
	               finished = true;
	            } catch (IllegalThreadStateException var19) {
	               Thread.currentThread();
	               Thread.sleep(500L);
	            }
	         }
	      } catch (Exception var20) {
	      } finally {
	         try {
	            if (in != null) {
	               in.close();
	            }
	         } catch (IOException var18) {
	         }

	         if (err != null) {
	            try {
	               err.close();
	            } catch (IOException var17) {
	            }
	         }

	      }

	      return exitValue;
	   }
}

 c:/bin/ffmpeg.exe  ffmepeg的位置

 -i  地址

-s  分辨率

-b 码率

-y 如果文件存在，再替换