java多线程下的视频转码

前言

      上一篇文章中介绍了linux下的java调用ffmpeg进行视频转码，完成之后发现存在一个问题：因为转码在服务器上需要很长时间，而当前页面需要等转码结束后才能响应跳转到视频列表页面，这个当然是不合理的了。所以，我采用了多线程进行处理，把视频的转码过程放在一个新的线程中完成，这样用户在上传页面的等待时间就会小很多了。关于java多线程的知识，这个博主总结的非常详细，http://blog.youkuaiyun.com/evankaka/article/details/44153709。

代码部分

//新开一个线程，去完成转码工作
		ExecutorService service = Executors.newSingleThreadExecutor();
		Runnable runnable = new Transcoding(absolutePath, filePath, mediaPicPath, storeName, userName, messageService, projectPath);
		service.submit(runnable);

这里是使用 ExecutorService 新建了一个线程，然后实现了Runnable接口，实例化了该方法，给Transcoding构造方法传了以上参数，下面看Transcoding类的代码。

import java.io.BufferedReader;
import java.io.File;
import java.io.InputStream;
import java.io.InputStreamReader;

import cn.xaut.video.domain.Message;
import cn.xaut.video.service.MessageService;

public class Transcoding implements Runnable{
	private String absolutePath;
	private String filePath;
	private String mediaPicPath;
	private String storeName;
	private String userName;
	private MessageService messageService = null;
	private String projectPath;
	

	public Transcoding(String absolutePath, String filePath,
			String mediaPicPath, String storeName, String userName, MessageService messageService, String projectPath) {
		super();
		this.absolutePath = absolutePath;
		this.filePath = filePath;
		this.mediaPicPath = mediaPicPath;
		this.storeName = storeName;
		this.userName = userName;
		this.messageService = messageService;
		this.projectPath = projectPath;
	}

	
	/**
	 * 视频格式转换方法，把其他视频转换为.mp4格式
	 * 
	 * @param absolutePath
	 *            输入文件
	 * @param filePath
	 *            输出文件
	 * @param mediaPicPath
	 *            截图保存地址
	 * @return
	 */
	public void executeCodecs(String absolutePath, String filePath,
			String mediaPicPath, String storeName,String userName, String projectPath) {
		String videoCommend = "ffmpeg -i "
				+ absolutePath
				+ " -vcodec libx264 -r 29.97 -b 768k -ar 24000 -ab 64k -s 1280x720 "
				+ filePath;
		String picCommend = "ffmpeg -ss 00:02:06 -i " + absolutePath
				+ " -f image2 -y " + mediaPicPath;
		boolean flag = false;
		flag = runCmd(videoCommend);
		System.out.println("videoCommend successful");
		flag = runCmd(picCommend);
		System.out.println("picCommend successful");
		String destPath = projectPath + File.separator + ".."
				+ File.separator + "tempVideo" + File.separator;
		String url = destPath + storeName;
		System.out.println(url);
		new File(url).delete();
		System.out.println("删除成功");
	}

	/**
	 * 运行命令
	 * 
	 * @param command
	 */
	public boolean runCmd(String command) {
		try {
			Runtime rt = Runtime.getRuntime();
			Process proc = rt.exec(command);
			InputStream stderr = proc.getErrorStream();
			InputStreamReader isr = new InputStreamReader(stderr);
			BufferedReader br = new BufferedReader(isr);
			String line = null;
			while ((line = br.readLine()) != null){
				System.out.println(line);
			}
			int exitVal = proc.waitFor();
			System.out.println("Process exitValue: " + exitVal);
			return true;
		} catch (Throwable t) {
			System.out.println(t);
			t.printStackTrace();
			return false;
		}

	}
	
	@Override
	public void run() {
		executeCodecs(absolutePath, filePath, mediaPicPath, storeName, userName, projectPath);
		Message msg = new Message();
		msg.setState("0");
		msg.setReceiver(0);
		msg.setUrl("videoAction_checkList.action"); 
		String content="有一个新的视频需要审核！";
		msg.setContent(content);
		messageService.save(msg);
		System.out.println("转码结束！");

	}
	
}

以上就是新建立一个线程处理视频转码的过程了。