java 调用ffmpeg_使用java调用FFMPEG进行转码

使用java调用FFMPEG进行转码

import java.io.BufferedReader;

import java.io.IOException;

import java.io.InputStream;

import java.io.InputStreamReader;

import java.io.OutputStream;

public class TestFFmpeg {

static String ffmpeg_cmd = "/home/andrew/Work/FFmpeg/ffmpeg-3.2/ffmpeg";

//static String in = "/home/andrew/Work/FFmpeg/ffmpeg-3.2/test_2200kbps.flv";

//static String out = "/home/andrew/Work/FFmpeg/ffmpeg-3.2/test_out.flv";

static String in = "rtmp://223.203.1.34:1936/live?vhost=cc.com/stream1_1";

static String out = "rtmp://223.203.1.34:1936/live?vhost=cc.com/stream2";

static Process p;

public static void main(String[] args) {

Runtime rt = Runtime.getRuntime() ;

int r = -1;

Thread stoppingThread;

Thread errorStream;

Thread inputStream;

System.out.println(in);

System.out.println(out);

String[] cmd1 = new String[] {ffmpeg_cmd, "-re", "-i", in, "-acodec", "aac", "-ar", "44100", "-vcodec", "copy", "-report" , "-y", "-f", "flv", out};

//String cmd1 = ffmpeg_cmd + " -re" + " -i " + in + " -acodec", " aac", " -ar" + " 44100" + " -vcodec" + " copy" + " -report" + " -y"," -f" + " flv " + out;

try {

System.out.println(cmd1);

p = rt.exec(cmd1);

StopTranscoder stopRunnable = new StopTranscoder(p);

stoppingThread = new Thread(stopRunnable);

stoppingThread.start();

final InputStream is1 = p.getErrorStream ();

final InputStream is2 = p.getInputStream ();

//启动两个线程，一个线程负责读标准输出流，另一个负责读标准错误流

GetStream streamErr = new GetStream(is1);

errorStream = new Thread(streamErr);

errorStream.start();

GetStream streamIn = new GetStream(is2);

inputStream = new Thread(streamIn);

inputStream.start();

System.out.println("waiting for");

try {

r = p.waitFor();

} catch (InterruptedException e) {

e.printStackTrace();

}

} catch (Exception e) {

e.printStackTrace();

}

System.out.println(r);

p.destroy();

}

}

class StopTranscoder implements Runnable {

private Process process = null;

public StopTranscoder(Process proc){

this.process = proc;

}

public void run() {

try {

System.out.println("kill before sleep");

Thread.sleep(10000);

System.out.println("kill after sleep");

this.process.destroy();

} catch (Exception e) {

e.printStackTrace();

}

}

}

class GetStream implements Runnable {

private InputStream is;

public GetStream(InputStream stream) {

is = stream;

}

public void run() {

BufferedReader br = new BufferedReader(new InputStreamReader(is));

try {

String line = null;

while ((line = br.readLine()) != null) {

if (line != null){

System.out.println(line);

}

}

} catch (IOException e) {

e.printStackTrace();

}

finally{

try {

is.close();

} catch (IOException e) {

e.printStackTrace();

}

}

}

}

执行FFMPEG

启动FFMPEG进程，Runtime.getRuntime().exec(cmd)

启动两个线程，一个线程负责读标准输出流，另一个负责读标准错误流

当Runtime对象调用exec(cmd)后，JVM会启动一个子进程，该进程会与JVM进程建立三个管道连接：标准输入，标准输出和标准错误流。假设该程序不断在向标准输出流和标准错误流写数据，而JVM不读取的话，当缓冲区满之后将无法继续写入数据，最终造成阻塞在waitfor()这里。

注释：

之前遇到过调用process.destroy()有可能无法使FFMPEG退出的情况，所以增加了类StopTranscoder()进行测试，但是没有复现之前的问题。