Android MP3录音实现

给APP做语音功能，必须考虑到IOS和Android平台的通用性。wav录音质量高，文件太大，AAC和AMR格式在IOS平台却不支持，所以采用libmp3lame把AudioRecord音频流直接转换成MP3格式。

声明一下，代码参考了http://blog.csdn.net/cboy017/article/details/8455629，这里只是借花献佛，把整个流程写得更详细。

这里采用的是最新的lame-3.99.5.tar。

可以去Lame官网下载，博文最后也有CSDN下载地址。官网地址：http://lame.sourceforge.net/

如果你对JNI和NDK完全不熟悉的话，请看前一篇博文 Android NDK开发之入门教程

先看一下项目文件目录：

开始Coding吧！

1 新建项目AndroidLameMP3。

2 创建JNI目录。

3 下载lame-3.99.5.tar。

解压，把子文件夹libmp3lame中的非.h和.c格式的文件删除后的剩余的所有文件和include下的lame.h放进一个新建的lame-3.99.5_libmp3lame文件夹中，最后把整个lame-3.99.5_libmp3lame文件夹拷贝到JNI目录下。

4 在com.example.lamemp3下创建MP3Recorder.class：

MP3Recorder.class

public class MP3Recorder {
private String mFilePath = null;
private int sampleRate = 0;
private boolean isRecording = false;
private boolean isPause = false;
private Handler handler = null;
/**
* 开始录音
*/
public static final int MSG_REC_STARTED = 1;
/**
* 结束录音
*/
public static final int MSG_REC_STOPPED = 2;
/**
* 暂停录音
*/
public static final int MSG_REC_PAUSE = 3;
/**
* 继续录音
*/
public static final int MSG_REC_RESTORE = 4;
/**
* 缓冲区挂了,采样率手机不支持
*/
public static final int MSG_ERROR_GET_MIN_BUFFERSIZE = -1;
/**
* 创建文件时扑街了
*/
public static final int MSG_ERROR_CREATE_FILE = -2;
/**
* 初始化录音器时扑街了
*/
public static final int MSG_ERROR_REC_START = -3;
/**
* 录音的时候出错
*/
public static final int MSG_ERROR_AUDIO_RECORD = -4;
/**
* 编码时挂了
*/
public static final int MSG_ERROR_AUDIO_ENCODE = -5;
/**
* 写文件时挂了
*/
public static final int MSG_ERROR_WRITE_FILE = -6;
/**
* 没法关闭文件流
*/
public static final int MSG_ERROR_CLOSE_FILE = -7;
public MP3Recorder() {
this.sampleRate = 8000;
}
/**
* 开片
*/
public void start() {
if (isRecording) {
return;
}
new Thread() {
@Override
public void run() {
String fileDir = StorageUtil.getSDPath() + "LameMP3/Voice/";
File dir = new File(fileDir);
if (!dir.exists()) {
dir.mkdirs();
}
mFilePath = StorageUtil.getSDPath() + "LameMP3/Voice/"
+ System.currentTimeMillis() + ".mp3";
System.out.println(mFilePath);
android.os.Process
.setThreadPriority(android.os.Process.THREAD_PRIORITY_URGENT_AUDIO);
// 根据定义好的几个配置，来获取合适的缓冲大小
final int minBufferSize = AudioRecord.getMinBufferSize(
sampleRate, AudioFormat.CHANNEL_IN_MONO,
AudioFormat.ENCODING_PCM_16BIT);
if (minBufferSize < 0) {
if (handler != null) {
handler.sendEmptyMessage(MSG_ERROR_GET_MIN_BUFFERSIZE);
}
return;
}
AudioRecord audioRecord = new AudioRecord(
MediaRecorder.AudioSource.MIC, sampleRate,
AudioFormat.CHANNEL_IN_MONO,
AudioFormat.ENCODING_PCM_16BIT, minBufferSize * 2);
// 5秒的缓冲
short[] buffer = new short[sampleRate * (16 / 8) * 1 * 5];
byte[] mp3buffer = new byte[(int) (7200 + buffer.length * 2 * 1.25)];
FileOutputStream output = null;
try {
output = new FileOutputStream(new File(mFilePath));
} catch (FileNotFoundException e) {
if (handler != null) {
handler.sendEmptyMessage(MSG_ERROR_CREATE_FILE);
}
return;
}
MP3Recorder.init(sampleRate, 1, sampleRate, 32);
isRecording = true; // 录音状态
isPause = false; // 录音状态
try {
try {
audioRecord.startRecording(); // 开启录音获取音频数据
} catch (IllegalStateException e) {
// 不给录音...
if (handler != null) {
handler.sendEmptyMessage(MSG_ERROR_REC_START);
}
return;
}
try {
// 开始录音
if (handler != null) {
handler.sendEmptyMessage(MSG_REC_STARTED);
}
int readSize = 0;
boolean pause = false;
while (isRecording) {
/*--暂停--*/
if (isPause) {
if (!pause) {
handler.sendEmptyMessage(MSG_REC_PAUSE);
pause = true;
}
continue;
}
if (pause) {
handler.sendEmptyMessage(MSG_REC_RESTORE);
pause = false;
}
/*--End--*/
/*--实时录音写数据--*/
readSize = audioRecord.read(buffer, 0,
minBufferSize);
if (readSize < 0) {
if (handler != null) {
handler.sendEmptyMessage(MSG_ERROR_AUDIO_RECORD);
}
break;
} else if (readSize == 0) {
;
} else {
int encResult = MP3Recorder.encode(buffer,
buffer, readSize, mp3buffer);
if (encResult < 0) {
if (handler != null) {
handler.sendEmptyMessage(MSG_ERROR_AUDIO_ENCODE);
}
break;
}
if (encResult != 0) {
try {
output.write(mp3buffer, 0, encResult);
} catch (IOException e) {
if (handler != null) {
handler.sendEmptyMessage(MSG_ERROR_WRITE_FILE);
}
break;
}
}
}
/*--End--*/
}
/*--录音完--*/
int flushResult = MP3Recorder.flush(mp3buffer);
if (flushResult < 0) {
if (handler != null) {
handler.sendEmptyMessage(MSG_ERROR_AUDIO_ENCODE);
}
}
if (flushResult != 0) {
try {
output.write(mp3buffer, 0, flushResult);
} catch (IOException e) {
if (handler != null) {
handler.sendEmptyMessage(MSG_ERROR_WRITE_FILE);
}
}
}
try {
output.close();
} catch (IOException e) {
if (handler != null) {
handler.sendEmptyMessage(MSG_ERROR_CLOSE_FILE);
}
}
/*--End--*/
} finally {
audioRecord.stop();
audioRecord.release();
}
} finally {
MP3Recorder.close();
isRecording = false;
}
if (handler != null) {
handler.sendEmptyMessage(MSG_REC_STOPPED);
}
}
}.start();
}
public void stop() {
isRecording = false;
}
public void pause() {
isPause = true;
}
public void restore() {
isPause = false;
}
public boolean isRecording() {
return isRecording;
}
public boolean isPaus() {
if (!isRecording) {
return false;
}
return isPause;
}
public String getFilePath() {
return mFilePath;
}
/**
* 录音状态管理
*
* @see RecMicToMp3#MSG_REC_STARTED
* @see RecMicToMp3#MSG_REC_STOPPED
* @see RecMicToMp3#MSG_REC_PAUSE
* @see RecMicToMp3#MSG_REC_RESTORE
* @see RecMicToMp3#MSG_ERROR_GET_MIN_BUFFERSIZE
* @see RecMicToMp3#MSG_ERROR_CREATE_FILE
* @see RecMicToMp3#MSG_ERROR_REC_START
* @see RecMicToMp3#MSG_ERROR_AUDIO_RECORD
* @see RecMicToMp3#MSG_ERROR_AUDIO_ENCODE
* @see RecMicToMp3#MSG_ERROR_WRITE_FILE
* @see RecMicToMp3#MSG_ERROR_CLOSE_FILE
*/
public void setHandle(Handler handler) {
this.handler = handler;
}
/*--以下为Native部分--*/
static {
System.loadLibrary("mp3lame");
}
/**
* 初始化录制参数
*/
public static void init(int inSamplerate, int outChannel,
int outSamplerate, int outBitrate) {
init(inSamplerate, outChannel, outSamplerate, outBitrate, 7);
}
/**
* 初始化录制参数 quality:0=很好很慢 9=很差很快
*/
public native static void init(int inSamplerate, int outChannel,
int outSamplerate, int outBitrate, int quality);
/**
* 音频数据编码(PCM左进,PCM右进,MP3输出)
*/
public native static int encode(short[] buffer_l, short[] buffer_r,
int samples, byte[] mp3buf);
/**
* 刷干净缓冲区
*/
public native static int flush(byte[] mp3buf);
/**
* 结束编码
*/
public native static void close();
}

5 在JNI文件夹下创建com_example_lamemp3_MP3Recorder.h头文件，在里面定义几个方法，然后在
com_example_lamemp3_MP3Recorder.c中实现。

com_example_lamemp3_MP3Recorder.h：

/* DO NOT EDIT THIS FILE - it is machine generated */
#include <jni.h>
/* Header for class com_kubility_demo_MP3Recorder */
#ifndef _Included_com_example_lamemp3_MP3Recorder
#define _Included_com_example_lamemp3_MP3Recorder
#ifdef __cplusplus
extern "C" {
#endif
/*
* Class: com_kubility_demo_MP3Recorder
* Method: init
* Signature: (IIIII)V
*/
JNIEXPORT void JNICALL Java_com_example_lamemp3_MP3Recorder_init
(JNIEnv *, jclass, jint, jint, jint, jint, jint);
/*
* Class: com_kubility_demo_MP3Recorder
* Method: encode
* Signature: ([S[SI[B)I
*/
JNIEXPORT jint JNICALL Java_com_example_lamemp3_MP3Recorder_encode
(JNIEnv *, jclass, jshortArray, jshortArray, jint, jbyteArray);
/*
* Class: com_kubility_demo_MP3Recorder
* Method: flush
* Signature: ([B)I
*/
JNIEXPORT jint JNICALL Java_com_example_lamemp3_MP3Recorder_flush
(JNIEnv *, jclass, jbyteArray);
/*
* Class: com_kubility_demo_MP3Recorder
* Method: close
* Signature: ()V
*/
JNIEXPORT void JNICALL Java_com_example_lamemp3_MP3Recorder_close
(JNIEnv *, jclass);
#ifdef __cplusplus
}
#endif
#endif

com_example_lamemp3_MP3Recorder.c：

#include "lame-3.99.5_libmp3lame/lame.h"
#include "com_example_lamemp3_MP3Recorder.h"
static lame_global_flags *glf = NULL;
JNIEXPORT void JNICALL Java_com_example_lamemp3_MP3Recorder_init(
JNIEnv *env, jclass cls, jint inSamplerate, jint outChannel,
jint outSamplerate, jint outBitrate, jint quality) {
if (glf != NULL) {
lame_close(glf);
glf = NULL;
}
glf = lame_init();
lame_set_in_samplerate(glf, inSamplerate);
lame_set_num_channels(glf, outChannel);
lame_set_out_samplerate(glf, outSamplerate);
lame_set_brate(glf, outBitrate);
lame_set_quality(glf, quality);
lame_init_params(glf);
}
JNIEXPORT jint JNICALL Java_com_example_lamemp3_MP3Recorder_encode(
JNIEnv *env, jclass cls, jshortArray buffer_l, jshortArray buffer_r,
jint samples, jbyteArray mp3buf) {
jshort* j_buffer_l = (*env)->GetShortArrayElements(env, buffer_l, NULL);
jshort* j_buffer_r = (*env)->GetShortArrayElements(env, buffer_r, NULL);
const jsize mp3buf_size = (*env)->GetArrayLength(env, mp3buf);
jbyte* j_mp3buf = (*env)->GetByteArrayElements(env, mp3buf, NULL);
int result = lame_encode_buffer(glf, j_buffer_l, j_buffer_r,
samples, j_mp3buf, mp3buf_size);
(*env)->ReleaseShortArrayElements(env, buffer_l, j_buffer_l, 0);
(*env)->ReleaseShortArrayElements(env, buffer_r, j_buffer_r, 0);
(*env)->ReleaseByteArrayElements(env, mp3buf, j_mp3buf, 0);
return result;
}
JNIEXPORT jint JNICALL Java_com_example_lamemp3_MP3Recorder_flush(
JNIEnv *env, jclass cls, jbyteArray mp3buf) {
const jsize mp3buf_size = (*env)->GetArrayLength(env, mp3buf);
jbyte* j_mp3buf = (*env)->GetByteArrayElements(env, mp3buf, NULL);
int result = lame_encode_flush(glf, j_mp3buf, mp3buf_size);
(*env)->ReleaseByteArrayElements(env, mp3buf, j_mp3buf, 0);
return result;
}
JNIEXPORT void JNICALL Java_com_example_lamemp3_MP3Recorder_close(
JNIEnv *env, jclass cls) {
lame_close(glf);
glf = NULL;
}

6 创建Android.mk，注意把com_example_lamemp3_MP3Recorder.c添加进去。

LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
LAME_LIBMP3_DIR := lame-3.99.5_libmp3lame
LOCAL_MODULE := mp3lame
LOCAL_SRC_FILES := $(LAME_LIBMP3_DIR)/bitstream.c $(LAME_LIBMP3_DIR)/fft.c $(LAME_LIBMP3_DIR)/id3tag.c $(LAME_LIBMP3_DIR)/mpglib_interface.c $(LAME_LIBMP3_DIR)/presets.c $(LAME_LIBMP3_DIR)/quantize.c $(LAME_LIBMP3_DIR)/reservoir.c $(LAME_LIBMP3_DIR)/tables.c $(LAME_LIBMP3_DIR)/util.c $(LAME_LIBMP3_DIR)/VbrTag.c $(LAME_LIBMP3_DIR)/encoder.c $(LAME_LIBMP3_DIR)/gain_analysis.c $(LAME_LIBMP3_DIR)/lame.c $(LAME_LIBMP3_DIR)/newmdct.c $(LAME_LIBMP3_DIR)/psymodel.c $(LAME_LIBMP3_DIR)/quantize_pvt.c $(LAME_LIBMP3_DIR)/set_get.c $(LAME_LIBMP3_DIR)/takehiro.c $(LAME_LIBMP3_DIR)/vbrquantize.c $(LAME_LIBMP3_DIR)/version.c com_example_lamemp3_MP3Recorder.c
include $(BUILD_SHARED_LIBRARY)

7 AndroidManifest.xml添加权限。

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.RECORD_AUDIO" />

8 创建Builder后（上篇中有详细介绍，这里不赘述），Clean，报错：

In file included from jni/lame-3.99.5_libmp3lame/bitstream.c:36:0:
jni/lame-3.99.5_libmp3lame/util.h:574:5: error: unknown type name 'ieee754_float32_t'
jni/lame-3.99.5_libmp3lame/util.h:574:40: error: unknown type name 'ieee754_float32_t'
make.exe: *** [obj/local/armeabi/objs/mp3lame/lame-3.99.5_libmp3lame/bitstream.o] Error 1

打开util.h
把 574行的 extern ieee754_float32_t fast_log2(ieee754_float32_t x);替换成extern float fast_log2(float x);

再次Clean，又报错：

jni/lame-3.99.5_libmp3lame/fft.c:47:32: fatal error: vector/lame_intrin.h: No such file or directory
compilation terminated.
make.exe: *** [obj/local/armeabi/objs/mp3lame/lame-3.99.5_libmp3lame/fft.o] Error 1

打开fft.c删除47行#include "vector/lame_intrin.h"

Clean还报错：

In file included from jni/lame-3.99.5_libmp3lame/presets.c:29:0:
jni/lame-3.99.5_libmp3lame/set_get.h:24:18: fatal error: lame.h: No such file or directory
compilation terminated.
make.exe: *** [obj/local/armeabi/objs/mp3lame/lame-3.99.5_libmp3lame/presets.o] Error 1

打开set_get.h，删除24行，#include <lame.h>

再次Clean，成功：

[armeabi] Compile thumb : mp3lame <= version.c
[armeabi] Compile thumb : mp3lame <= com_example_lamemp3_MP3Recorder.c
[armeabi] SharedLibrary : libmp3lame.so
[armeabi] Install : libmp3lame.so => libs/armeabi/libmp3lame.so