很多朋友都知道，ffmpeg是一个功能强大的多媒体处理工具，可惜它并不是java语言开发，如果需要在java项目中使用时，得自己写很多代码，幸好github上有一个开源项目jave2 把ffmpeg做了封装，很大程度上简化了开发，使用方法如下：

先添加依赖项

<dependency>
    <groupId>ws.schild</groupId>
    <artifactId>jave-all-deps</artifactId>
    <version>3.1.1</version>
</dependency>

 

以下是一些常用示例：

1、获取音频文件的编码信息

   MultimediaInfo getMediaInfo() {
        String sourceFilePath = "/Users/jimmy/Downloads/bgm.wav";
        File file = new File(sourceFilePath);
        if (file != null && file.exists()) {
            try {
                MultimediaObject multimediaObject = new MultimediaObject(file);
                MultimediaInfo m = multimediaObject.getInfo();
                return m;
            } catch (Exception e) {
                e.printStackTrace();

            }
        }
        return null;
    }

System.out.println(getMediaInfo()); 输出如下：

ws.schild.jave.info.MultimediaInfo (format=wav (metadata={encoder=Lavf58.27.103}, duration=101850, video=null, audio=ws.schild.jave.info.AudioInfo (decoder=pcm_s16le ([1][0][0][0] / 0x0001), samplingRate=44100, channels=2, bitRate=1411000))

从上面可以看出，该文件是wav格式，时长为101.850秒，编码格式为pcm_s16le，采集率为44100，双声道，bit率为1411000

 

2、wav转mp3

boolean convert2Mp3() {
        String sourceFilePath = "/Users/jimmy/Downloads/bgm.wav";
        String targetFilePath = "/Users/jimmy/Downloads/bgm.mp3";
        try {
            File source = new File(sourceFilePath);
            File target = new File(targetFilePath);

            //Audio Attributes
            AudioAttributes audio = new AudioAttributes();
            audio.setCodec("libmp3lame");
            audio.setBitRate(64000);
            audio.setChannels(2);
            audio.setSamplingRate(44100);

            //Encoding attributes
            EncodingAttributes attrs = new EncodingAttributes();
            attrs.setInputFormat("wav");
            attrs.setOutputFormat("mp3");
            attrs.setAudioAttributes(audio);

            //Encode
            Encoder encoder = new Encoder();
            encoder.encode(new MultimediaObject(source), target, attrs);

        } catch (Exception ex) {
            ex.printStackTrace();
            return false;
        }
        return true;
    }

　　

3、转换编码格式

    static boolean changeCode() {
        String sourceFilePath = "/Users/jimmy/Downloads/bgm.wav";
        String targetFilePath = "/Users/jimmy/Downloads/bgm_2.wav";

        //Audio Attributes
        AudioAttributes audio = new AudioAttributes();
        audio.setCodec("pcm_u8");
        audio.setBitRate(64000);
        audio.setChannels(2);
        audio.setSamplingRate(8000);

        //Encoding attributes
        EncodingAttributes attrs = new EncodingAttributes();
        attrs.setInputFormat("wav");
        attrs.setOutputFormat("wav");
        attrs.setAudioAttributes(audio);

        //Encode
        Encoder encoder = new Encoder();
        try {
            encoder.encode(new MultimediaObject(new File(sourceFilePath)), new File(targetFilePath), attrs);

            //辅助输出，观察编码格式的变化
            MultimediaObject srcObj = new MultimediaObject(new File(sourceFilePath));
            MultimediaObject targetObj = new MultimediaObject(new File(targetFilePath));
            System.out.println(srcObj.getInfo());
            System.out.println(targetObj.getInfo());
        } catch (Exception ex) {
            ex.printStackTrace();
            return false;
        }
        return true;
    }

第7行，设置了新的编码pcm_u8

 

4、分离左右声道

boolean splitChannel() {
        String source = "/Users/jimmy/Downloads/bgm.wav";
        String left = "/Users/jimmy/Downloads/bgm_left.wav";
        String right = "/Users/jimmy/Downloads/bgm_right.wav";
        File leftFile = new File(left);
        File rightFile = new File(right);
        if (leftFile.exists()) {
            leftFile.delete();
        }

        if (rightFile.exists()) {
            rightFile.delete();
        }
        DefaultFFMPEGLocator locator = new DefaultFFMPEGLocator();
        ProcessWrapper ffmpeg = locator.createExecutor();
        ffmpeg.addArgument("-i");
        ffmpeg.addArgument(source);
        ffmpeg.addArgument("-map_channel");
        ffmpeg.addArgument("0.0.0");
        ffmpeg.addArgument(left);
        ffmpeg.addArgument("-map_channel");
        ffmpeg.addArgument("0.0.1");
        ffmpeg.addArgument(right);
        BufferedReader br = null;
        try {
            ffmpeg.execute();
            br = new BufferedReader(new InputStreamReader(ffmpeg.getErrorStream()));
            String line;
            while ((line = br.readLine()) != null) {
                //输出处理过程中的日志（辅助观察处理过程）
                System.out.println(line);
            }
        } catch (IOException e) {
            e.printStackTrace();
            return false;
        } finally {
            try {
                if (br != null) {
                    br.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

        try {
            //辅助输出，观察编码格式的变化
            MultimediaObject srcObj = new MultimediaObject(leftFile);
            MultimediaObject targetObj = new MultimediaObject(rightFile);
            System.out.println(srcObj.getInfo());
            System.out.println(targetObj.getInfo());
        } catch (Exception ex) {
            ex.printStackTrace();
        }

        return true;
    }

 声道分离后，会生成2个文件，分别对应于左右声道。

　　

5、拼接音频（比如：把某段音频重复N次，合成1个新音频）

boolean mergeAudio() {
//        ffmpeg -i bullet.wav -i bullet.wav -i bullet.wav -filter_complex '[0:0] [1:0] concat=n=3:v=0:a=1 [a]' -map [a] bullet_3.wav

        //先生成要拼接的音频清单
        int times = 5;

        String src = "/Users/jimmy/Downloads/bullet.wav";
        String target = "/Users/jimmy/Downloads/bullet_" + times + ".wav";

        File targetFile = new File(target);
        if (targetFile.exists()) {
            targetFile.delete();
        }

        DefaultFFMPEGLocator locator = new DefaultFFMPEGLocator();
        ProcessWrapper ffmpeg = locator.createExecutor();
        for (int i = 1; i <= times; i++) {
            ffmpeg.addArgument("-i");
            ffmpeg.addArgument(src);
        }
        ffmpeg.addArgument("-filter_complex");
        ffmpeg.addArgument("[0:0] [1:0] concat=n=" + times + ":v=0:a=1 [a]");
        ffmpeg.addArgument("-map");
        ffmpeg.addArgument("[a]");

        ffmpeg.addArgument(target);
        BufferedReader br = null;
        try {
            ffmpeg.execute();
            br = new BufferedReader(new InputStreamReader(ffmpeg.getErrorStream()));
            String line;
            while ((line = br.readLine()) != null) {
                //输出处理过程中的日志（辅助观察处理过程）
                System.out.println(line);
            }
        } catch (IOException e) {
            e.printStackTrace();
            return false;
        } finally {
            try {
                if (br != null) {
                    br.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return true;
    }

　　

6、截取音频中的某一段

void cut() throws EncoderException {
        String src = "/Users/jimmy/Downloads/bgm.wav";
        String target = "/Users/jimmy/Downloads/bgm_1_3.wav";

        File targetFile = new File(target);
        if (targetFile.exists()) {
            targetFile.delete();
        }

        File srcFile = new File(src);
        MultimediaObject srcMultiObj = new MultimediaObject(srcFile);
        MultimediaInfo srcMediaInfo = srcMultiObj.getInfo();

        Encoder encoder = new Encoder();


        EncodingAttributes encodingAttributes = new EncodingAttributes();
        //设置起始偏移量(秒)
        encodingAttributes.setOffset(1.0F);
        //设置切片的音频长度(秒)
        encodingAttributes.setDuration(2.0F);

        //设置音频属性
        AudioAttributes audio = new AudioAttributes();
        audio.setBitRate(srcMediaInfo.getAudio().getBitRate());
        audio.setSamplingRate(srcMediaInfo.getAudio().getSamplingRate());
        audio.setChannels(srcMediaInfo.getAudio().getChannels());

        //如果截取的时候，希望同步调整编码，可以设置不同的编码
//        audio.setCodec("pcm_u8");
        audio.setCodec(srcMediaInfo.getAudio().getDecoder().split(" ")[0]);
        encodingAttributes.setInputFormat("wav");
        encodingAttributes.setAudioAttributes(audio);

        //写文件
        encoder.encode(srcMultiObj, new File(target), encodingAttributes);

    }

　　

最后说一个可能会存在的问题：默认情况下，jave2在执行时，会把ffmpeg可执行文件释放到"java.io.tmpdir"临时目录下，但在tomcat等容器下执行时，如果启用tomcat的用户，与java应用的执行用户不同，可能会存在无写入权限的问题。遇到这种情况，可以先用代码把java.io.tmpdir这个系统变量，指到其它有权限的目录，执行完后，再还原回来

 String oldTmpDir = System.getProperty("java.io.tmpdir");
        try {
            System.setProperty("java.io.tmpdir", "有权限写入的新临时目录");
            // todo （jave2的其它处理）
        }  finally {
            System.setProperty("java.io.tmpdir", oldTmpDir);
        }