用java小例题说明更直观：(可以直接编译运行)

环境我在windows平台下测试的。。。

需要在e:/下有ffmpeg.exe;mencoder.exe;drv43260.dll;pncrt.dll共4个文件。

如何得到这4个文件参考文章http://blog.sina.com.cn/u/4a424eca010005kb

还要在e:/input下放各种文件名为a的以下各种视频文件；还要e:/output；java程序执行后能得到一个a.flv的已转换的文件。

ffmpeg.exe能解析的格式：(asx，asf，mpg，wmv，3gp，mp4，mov，avi，flv等)

对ffmpeg.exe无法解析的文件格式(wmv9，rm，rmvb等),

可以先用别的工具(mencoder)转换为avi(ffmpeg能解析的)格式；

mencoder.exe;drv43260.dll;pncrt.dll这3个文件是为文件格式(wmv9，rm，rmvb等)

转换为avi(ffmpeg能解析的)格式准备的；再把转换好的avi文件再用ffmpeg.exe转换成flv格式的视频文件。。。

package com.jh.test;

import java.io.File;

import java.io.IOException;

import java.util.ArrayList;

import java.util.List;

public class ConvertVideo {

private static String inputPath = "";

private static String outputPath = "";

private static String ffmpegPath = "";

public static void main(String args[]) throws IOException {

getPath();

if (!checkfile(inputPath)) {

System.out.println(inputPath + " is not file");

return;

}

if (process()) {

System.out.println("ok");

}

}

public static void getPath(){

// 先获取当前项目路径，在获得源文件、目标文件、转换器的路径

File diretory = new File("");

try {

String currPath = diretory.getAbsolutePath();

//视频的地址

inputPath = "C:\\平行四边形面积.flv";

//视频转完格式存放地址

outputPath = "E:\\mp4\\";

//转换视频的插件位置

ffmpegPath = "G:\\工具类\\ffmpeg-20171225-be2da4c-win64-static\\ffmpeg-20171225-be2da4c-win64-static\\bin\\";

System.out.println(currPath);

}

catch (Exception e) {

System.out.println("getPath出错");

}

}

public static boolean process() {

int type = checkContentType();

boolean status = false;

System.out.println("直接转成mp4格式");

status = processMp4(inputPath);// 直接转成mp4格式

return status;

}

private static int checkContentType() {

String type = inputPath.substring(inputPath.lastIndexOf(".") + 1, inputPath.length())

.toLowerCase();

// ffmpeg能解析的格式：(asx，asf，mpg，wmv，3gp，mp4，mov，avi，flv等)

if (type.equals("avi")) {

return 0;

} else if (type.equals("mpg")) {

return 0;

} else if (type.equals("wmv")) {

return 0;

} else if (type.equals("3gp")) {

return 0;

} else if (type.equals("mov")) {

return 0;

} else if (type.equals("mp4")) {

return 0;

} else if (type.equals("asf")) {

return 0;

} else if (type.equals("asx")) {

return 0;

} else if (type.equals("flv")) {

return 0;

}

// 对ffmpeg无法解析的文件格式(wmv9，rm，rmvb等),

// 可以先用别的工具(mencoder)转换为avi(ffmpeg能解析的)格式.

else if (type.equals("wmv9")) {

return 1;

} else if (type.equals("rm")) {

return 1;

} else if (type.equals("rmvb")) {

return 1;

}

return 9;

}

private static boolean checkfile(String path) {

File file = new File(path);

if (!file.isFile()) {

return false;

}

return true;

}

// 对ffmpeg无法解析的文件格式(wmv9，rm，rmvb等), 可以先用别的工具(mencoder)转换为avi(ffmpeg能解析的)格式.

private static String processAVI(int type) {

Listcommend = new ArrayList();

commend.add(ffmpegPath + "mencoder");

commend.add(inputPath);

commend.add("-oac");

commend.add("lavc");

commend.add("-lavcopts");

commend.add("acodec=mp3:abitrate=64");

commend.add("-ovc");

commend.add("xvid");

commend.add("-xvidencopts");

commend.add("bitrate=600");

commend.add("-of");

commend.add("mp4");

commend.add("-o");

commend.add(outputPath + "a.AVI");

try {

ProcessBuilder builder = new ProcessBuilder();

Process process = builder.command(commend).redirectErrorStream(true).start();

new PrintStream(process.getInputStream());

new PrintStream(process.getErrorStream());

process.waitFor();

return outputPath + "a.AVI";

} catch (Exception e) {

e.printStackTrace();

return null;

}

}

// ffmpeg能解析的格式：(asx，asf，mpg，wmv，3gp，mp4，mov，avi，flv等)

private static boolean processFlv(String oldfilepath) {

if (!checkfile(inputPath)) {

System.out.println(oldfilepath + " is not file");

return false;

}

Listcommand = new ArrayList();

command.add(ffmpegPath + "ffmpeg");

command.add("-i");

command.add(oldfilepath);

command.add("-ab");

command.add("56");

command.add("-ar");

command.add("22050");

command.add("-qscale");

command.add("8");

command.add("-r");

command.add("15");

command.add("-s");

command.add("600x500");

command.add(outputPath + "a.flv");

try {

// 方案1

// Process videoProcess = Runtime.getRuntime().exec(ffmpegPath + "ffmpeg -i " + oldfilepath

// + " -ab 56 -ar 22050 -qscale 8 -r 15 -s 600x500 "

// + outputPath + "a.flv");

// 方案2

Process videoProcess = new ProcessBuilder(command).redirectErrorStream(true).start();

new PrintStream(videoProcess.getErrorStream()).start();

new PrintStream(videoProcess.getInputStream()).start();

videoProcess.waitFor();

return true;

} catch (Exception e) {

e.printStackTrace();

return false;

}

}

private static boolean processMp4(String oldfilepath) {

if (!checkfile(inputPath)) {

System.out.println(oldfilepath + " is not file");

return false;

}

Listcommand = new ArrayList();

command.add(ffmpegPath + "ffmpeg");

command.add("-i");

command.add(oldfilepath);

command.add("-c:v");

command.add("libx264");

command.add("-mbd");

command.add("0");

command.add("-c:a");

command.add("aac");

command.add("-strict");

command.add("-2");

command.add("-pix_fmt");

command.add("yuv420p");

command.add("-movflags");

command.add("faststart");

command.add(outputPath + "a.mp4");

try {

// 方案1

// Process videoProcess = Runtime.getRuntime().exec(ffmpegPath + "ffmpeg -i " + oldfilepath

// + " -ab 56 -ar 22050 -qscale 8 -r 15 -s 600x500 "

// + outputPath + "a.flv");

// 方案2

Process videoProcess = new ProcessBuilder(command).redirectErrorStream(true).start();

new PrintStream(videoProcess.getErrorStream()).start();

new PrintStream(videoProcess.getInputStream()).start();

videoProcess.waitFor();

return true;

} catch (Exception e) {

e.printStackTrace();

return false;

}

}

}

class PrintStream extends Thread

{

java.io.InputStream is = null;

public PrintStream(java.io.InputStream is)

{is = is;

}

public void run()

{

try

{

while(this != null)

{

int _ch = __is.read();

if(_ch != -1)

System.out.print((char)_ch);

else break;

}

}

catch (Exception e)

{

e.printStackTrace();

}

}

}