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
代码语言：javascript复制<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
代码语言：javascript复制 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
代码语言：javascript复制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
代码语言：javascript复制 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
代码语言：javascript复制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）
代码语言：javascript复制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
代码语言：javascript复制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
代码语言：javascript复制 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);
}
