Android提供了两个API用于实现录音功能：android.media.AudioRecord、android.media.MediaRecorder。
网上有很多谈论这两个类的资料。现在大致总结下：
1、AudioRecord
主要是实现边录边播（AudioRecord+AudioTrack）以及对音频的实时处理（如会说话的汤姆猫、语音）
优点：语音的实时处理，可以用代码实现各种音频的封装
缺点：输出是PCM语音数据，如果保存成音频文件，是不能够被播放器播放的，所以必须先写代码实现数据编码以及压缩
示例：
使用AudioRecord类录音，并实现WAV格式封装。录音20s，输出的音频文件大概为3.5M左右（已写测试代码）
2、MediaRecorder
已经集成了录音、编码、压缩等，支持少量的录音音频格式，大概有.aac（API = 16） .amr .3gp
优点：大部分以及集成，直接调用相关接口即可，代码量小
缺点：无法实时处理音频；输出的音频格式不是很多，例如没有输出mp3格式文件
示例：
使用MediaRecorder类录音，输出amr格式文件。录音20s，输出的音频文件大概为33K（已写测试代码）
3、音频格式比较
WAV格式：录音质量高，但是压缩率小，文件大
AAC格式：相对于mp3，AAC格式的音质更佳，文件更小；有损压缩；一般苹果或者Android SDK4.1.2（API 16）及以上版本支持播放
AMR格式：压缩比比较大，但相对其他的压缩格式质量比较差，多用于人声，通话录音
至于常用的mp3格式，使用MediaRecorder没有该视频格式输出。一些人的做法是使用AudioRecord录音，然后编码成wav格式，再转换成mp3格式
再贴上一些测试工程。
功能描述：
1、点击“录音WAV文件”，开始录音。录音完成后，生成文件/sdcard/FinalAudio.wav
2、点击“录音AMR文件”，开始录音。录音完成后，生成文件/sdcard/FinalAudio.amr
3、点击“停止录音”，停止录音，并显示录音输出文件以及该文件大小。
大致代码如下：
1、AudioRecord录音，封装成WAV格式
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package com.example.audiorecordtest;import java.io.File;import java.io.FileInputStream;import java.io.FileNotFoundException;import java.io.FileOutputStream;import java.io.IOException;import android.media.AudioFormat;import android.media.AudioRecord;public class AudioRecordFunc { // 缓冲区字节大小 private int bufferSizeInBytes = 0; //AudioName裸音频数据文件 ，麦克风 private String AudioName = ""; //NewAudioName可播放的音频文件 private String NewAudioName = ""; private AudioRecord audioRecord; private boolean isRecord = false;// 设置正在录制的状态 private static AudioRecordFunc mInstance; private AudioRecordFunc(){ } public synchronized static AudioRecordFunc getInstance() { if(mInstance == null) mInstance = new AudioRecordFunc(); return mInstance; } public int startRecordAndFile() { //判断是否有外部存储设备sdcard if(AudioFileFunc.isSdcardExit()) { if(isRecord) { return ErrorCode.E_STATE_RECODING; } else { if(audioRecord == null) creatAudioRecord(); audioRecord.startRecording(); // 让录制状态为true isRecord = true; // 开启音频文件写入线程 new Thread(new AudioRecordThread()).start(); return ErrorCode.SUCCESS; } } else { return ErrorCode.E_NOSDCARD; } } public void stopRecordAndFile() { close(); } public long getRecordFileSize(){ return AudioFileFunc.getFileSize(NewAudioName); } private void close() { if (audioRecord != null) { System.out.println("stopRecord"); isRecord = false;//停止文件写入 audioRecord.stop(); audioRecord.release();//释放资源 audioRecord = null; } } private void creatAudioRecord() { // 获取音频文件路径 AudioName = AudioFileFunc.getRawFilePath(); NewAudioName = AudioFileFunc.getWavFilePath(); // 获得缓冲区字节大小 bufferSizeInBytes = AudioRecord.getMinBufferSize(AudioFileFunc.AUDIO_SAMPLE_RATE, AudioFormat.CHANNEL_IN_STEREO, AudioFormat.ENCODING_PCM_16BIT); // 创建AudioRecord对象 audioRecord = new AudioRecord(AudioFileFunc.AUDIO_INPUT, AudioFileFunc.AUDIO_SAMPLE_RATE, AudioFormat.CHANNEL_IN_STEREO, AudioFormat.ENCODING_PCM_16BIT, bufferSizeInBytes); } class AudioRecordThread implements Runnable { @Override public void run() { writeDateTOFile();//往文件中写入裸数据 copyWaveFile(AudioName, NewAudioName);//给裸数据加上头文件 } } /** * 这里将数据写入文件，但是并不能播放，因为AudioRecord获得的音频是原始的裸音频， * 如果需要播放就必须加入一些格式或者编码的头信息。但是这样的好处就是你可以对音频的 裸数据进行处理，比如你要做一个爱说话的TOM * 猫在这里就进行音频的处理，然后重新封装 所以说这样得到的音频比较容易做一些音频的处理。 */ private void writeDateTOFile() { // new一个byte数组用来存一些字节数据，大小为缓冲区大小 byte[] audiodata = new byte[bufferSizeInBytes]; FileOutputStream fos = null; int readsize = 0; try { File file = new File(AudioName); if (file.exists()) { file.delete(); } fos = new FileOutputStream(file);// 建立一个可存取字节的文件 } catch (Exception e) { e.printStackTrace(); } while (isRecord == true) { readsize = audioRecord.read(audiodata, 0, bufferSizeInBytes); if (AudioRecord.ERROR_INVALID_OPERATION != readsize && fos!=null) { try { fos.write(audiodata); } catch (IOException e) { e.printStackTrace(); } } } try { if(fos != null) fos.close();// 关闭写入流 } catch (IOException e) { e.printStackTrace(); } } // 这里得到可播放的音频文件 private void copyWaveFile(String inFilename, String outFilename) { FileInputStream in = null; FileOutputStream out = null; long totalAudioLen = 0; long totalDataLen = totalAudioLen + 36; long longSampleRate = AudioFileFunc.AUDIO_SAMPLE_RATE; int channels = 2; long byteRate = 16 * AudioFileFunc.AUDIO_SAMPLE_RATE * channels / 8; byte[] data = new byte[bufferSizeInBytes]; try { in = new FileInputStream(inFilename); out = new FileOutputStream(outFilename); totalAudioLen = in.getChannel().size(); totalDataLen = totalAudioLen + 36; WriteWaveFileHeader(out, totalAudioLen, totalDataLen, longSampleRate, channels, byteRate); while (in.read(data) != -1) { out.write(data); } in.close(); out.close(); } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } } /** * 这里提供一个头信息。插入这些信息就可以得到可以播放的文件。 * 为我为啥插入这44个字节，这个还真没深入研究，不过你随便打开一个wav * 音频的文件，可以发现前面的头文件可以说基本一样哦。每种格式的文件都有 * 自己特有的头文件。 */ private void WriteWaveFileHeader(FileOutputStream out, long totalAudioLen, long totalDataLen, long longSampleRate, int channels, long byteRate) throws IOException { byte[] header = new byte[44]; header[0] = 'R'; // RIFF/WAVE header header[1] = 'I'; header[2] = 'F'; header[3] = 'F'; header[4] = (byte) (totalDataLen & 0xff); header[5] = (byte) ((totalDataLen >> 8) & 0xff); header[6] = (byte) ((totalDataLen >> 16) & 0xff); header[7] = (byte) ((totalDataLen >> 24) & 0xff); header[8] = 'W'; header[9] = 'A'; header[10] = 'V'; header[11] = 'E'; header[12] = 'f'; // 'fmt ' chunk header[13] = 'm'; header[14] = 't'; header[15] = ' '; header[16] = 16; // 4 bytes: size of 'fmt ' chunk header[17] = 0; header[18] = 0; header[19] = 0; header[20] = 1; // format = 1 header[21] = 0; header[22] = (byte) channels; header[23] = 0; header[24] = (byte) (longSampleRate & 0xff); header[25] = (byte) ((longSampleRate >> 8) & 0xff); header[26] = (byte) ((longSampleRate >> 16) & 0xff); header[27] = (byte) ((longSampleRate >> 24) & 0xff); header[28] = (byte) (byteRate & 0xff); header[29] = (byte) ((byteRate >> 8) & 0xff); header[30] = (byte) ((byteRate >> 16) & 0xff); header[31] = (byte) ((byteRate >> 24) & 0xff); header[32] = (byte) (2 * 16 / 8); // block align header[33] = 0; header[34] = 16; // bits per sample header[35] = 0; header[36] = 'd'; header[37] = 'a'; header[38] = 't'; header[39] = 'a'; header[40] = (byte) (totalAudioLen & 0xff); header[41] = (byte) ((totalAudioLen >> 8) & 0xff); header[42] = (byte) ((totalAudioLen >> 16) & 0xff); header[43] = (byte) ((totalAudioLen >> 24) & 0xff); out.write(header, 0, 44); } } |
2、MediaRecorder录音，输出amr格式音频
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package com.example.audiorecordtest;import java.io.File;import java.io.IOException;import android.media.MediaRecorder;public class MediaRecordFunc { private boolean isRecord = false; private MediaRecorder mMediaRecorder; private MediaRecordFunc(){ } private static MediaRecordFunc mInstance; public synchronized static MediaRecordFunc getInstance(){ if(mInstance == null) mInstance = new MediaRecordFunc(); return mInstance; } public int startRecordAndFile(){ //判断是否有外部存储设备sdcard if(AudioFileFunc.isSdcardExit()) { if(isRecord) { return ErrorCode.E_STATE_RECODING; } else { if(mMediaRecorder == null) createMediaRecord(); try{ mMediaRecorder.prepare(); mMediaRecorder.start(); // 让录制状态为true isRecord = true; return ErrorCode.SUCCESS; }catch(IOException ex){ ex.printStackTrace(); return ErrorCode.E_UNKOWN; } } } else { return ErrorCode.E_NOSDCARD; } } public void stopRecordAndFile(){ close(); } public long getRecordFileSize(){ return AudioFileFunc.getFileSize(AudioFileFunc.getAMRFilePath()); } private void createMediaRecord(){ /* ①Initial：实例化MediaRecorder对象 */ mMediaRecorder = new MediaRecorder(); /* setAudioSource/setVedioSource*/ mMediaRecorder.setAudioSource(AudioFileFunc.AUDIO_INPUT);//设置麦克风 /* 设置输出文件的格式：THREE_GPP/MPEG-4/RAW_AMR/Default * THREE_GPP(3gp格式，H263视频/ARM音频编码)、MPEG-4、RAW_AMR(只支持音频且音频编码要求为AMR_NB) */ mMediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.DEFAULT); /* 设置音频文件的编码：AAC/AMR_NB/AMR_MB/Default */ mMediaRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.DEFAULT); /* 设置输出文件的路径 */ File file = new File(AudioFileFunc.getAMRFilePath()); if (file.exists()) { file.delete(); } mMediaRecorder.setOutputFile(AudioFileFunc.getAMRFilePath()); } private void close(){ if (mMediaRecorder != null) { System.out.println("stopRecord"); isRecord = false; mMediaRecorder.stop(); mMediaRecorder.release(); mMediaRecorder = null; } }} |
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3、其他文件
AudioFileFunc.java
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package com.example.audiorecordtest;import java.io.File;import android.media.MediaRecorder;import android.os.Environment;public class AudioFileFunc { //音频输入-麦克风 public final static int AUDIO_INPUT = MediaRecorder.AudioSource.MIC; //采用频率 //44100是目前的标准，但是某些设备仍然支持22050，16000，11025 public final static int AUDIO_SAMPLE_RATE = 44100; //44.1KHz,普遍使用的频率 //录音输出文件 private final static String AUDIO_RAW_FILENAME = "RawAudio.raw"; private final static String AUDIO_WAV_FILENAME = "FinalAudio.wav"; public final static String AUDIO_AMR_FILENAME = "FinalAudio.amr"; /** * 判断是否有外部存储设备sdcard * @return true | false */ public static boolean isSdcardExit(){ if (Environment.getExternalStorageState().equals(android.os.Environment.MEDIA_MOUNTED)) return true; else return false; } /** * 获取麦克风输入的原始音频流文件路径 * @return */ public static String getRawFilePath(){ String mAudioRawPath = ""; if(isSdcardExit()){ String fileBasePath = Environment.getExternalStorageDirectory().getAbsolutePath(); mAudioRawPath = fileBasePath+"/"+AUDIO_RAW_FILENAME; } return mAudioRawPath; } /** * 获取编码后的WAV格式音频文件路径 * @return */ public static String getWavFilePath(){ String mAudioWavPath = ""; if(isSdcardExit()){ String fileBasePath = Environment.getExternalStorageDirectory().getAbsolutePath(); mAudioWavPath = fileBasePath+"/"+AUDIO_WAV_FILENAME; } return mAudioWavPath; } /** * 获取编码后的AMR格式音频文件路径 * @return */ public static String getAMRFilePath(){ String mAudioAMRPath = ""; if(isSdcardExit()){ String fileBasePath = Environment.getExternalStorageDirectory().getAbsolutePath(); mAudioAMRPath = fileBasePath+"/"+AUDIO_AMR_FILENAME; } return mAudioAMRPath; } /** * 获取文件大小 * @param path,文件的绝对路径 * @return */ public static long getFileSize(String path){ File mFile = new File(path); if(!mFile.exists()) return -1; return mFile.length(); }} |
4、其他文件
ErrorCode.java
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package com.example.audiorecordtest;import android.content.Context;import android.content.res.Resources.NotFoundException;public class ErrorCode { public final static int SUCCESS = 1000; public final static int E_NOSDCARD = 1001; public final static int E_STATE_RECODING = 1002; public final static int E_UNKOWN = 1003; public static String getErrorInfo(Context vContext, int vType) throws NotFoundException { switch(vType) { case SUCCESS: return "success"; case E_NOSDCARD: return vContext.getResources().getString(R.string.error_no_sdcard); case E_STATE_RECODING: return vContext.getResources().getString(R.string.error_state_record); case E_UNKOWN: default: return vContext.getResources().getString(R.string.error_unknown); } }} |
5、string.xml
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<?xml version="1.0" encoding="utf-8"?><resources> <string name="app_name">AudioRecordTest</string> <string name="hello_world">测试AudioRecord，实现录音功能</string> <string name="menu_settings">Settings</string> <string name="view_record_wav">录音WAV文件</string> <string name="view_record_amr">录音AMR文件</string> <string name="view_stop">停止录音</string> <string name="error_no_sdcard">没有SD卡，无法存储录音数据</string> <string name="error_state_record">正在录音中，请先停止录音</string> <string name="error_unknown">无法识别的错误</string></resources> |
6、主程序MainActivity
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package com.example.audiorecordtest; import android.app.Activity;import android.os.Bundle;import android.os.Handler;import android.os.Message;import android.util.Log;import android.view.Menu;import android.view.View;import android.widget.Button;import android.widget.TextView; public class MainActivity extends Activity { private final static int FLAG_WAV = 0; private final static int FLAG_AMR = 1; private int mState = -1; //-1:没再录制，0：录制wav，1：录制amr private Button btn_record_wav; private Button btn_record_amr; private Button btn_stop; private TextView txt; private UIHandler uiHandler; private UIThread uiThread; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); findViewByIds(); setListeners(); init(); } @Override public boolean onCreateOptionsMenu(Menu menu) { // Inflate the menu; this adds items to the action bar if it is present. getMenuInflater().inflate(R.menu.activity_main, menu); return true; } private void findViewByIds(){ btn_record_wav = (Button)this.findViewById(R.id.btn_record_wav); btn_record_amr = (Button)this.findViewById(R.id.btn_record_amr); btn_stop = (Button)this.findViewById(R.id.btn_stop); txt = (TextView)this.findViewById(R.id.text); } private void setListeners(){ btn_record_wav.setOnClickListener(btn_record_wav_clickListener); btn_record_amr.setOnClickListener(btn_record_amr_clickListener); btn_stop.setOnClickListener(btn_stop_clickListener); } private void init(){ uiHandler = new UIHandler(); } private Button.OnClickListener btn_record_wav_clickListener = new Button.OnClickListener(){ public void onClick(View v){ record(FLAG_WAV); } }; private Button.OnClickListener btn_record_amr_clickListener = new Button.OnClickListener(){ public void onClick(View v){ record(FLAG_AMR); } }; private Button.OnClickListener btn_stop_clickListener = new Button.OnClickListener(){ public void onClick(View v){ stop(); } }; /** * 开始录音 * @param mFlag，0：录制wav格式，1：录音amr格式 */ private void record(int mFlag){ if(mState != -1){ Message msg = new Message(); Bundle b = new Bundle();// 存放数据 b.putInt("cmd",CMD_RECORDFAIL); b.putInt("msg", ErrorCode.E_STATE_RECODING); msg.setData(b); uiHandler.sendMessage(msg); // 向Handler发送消息,更新UI return; } int mResult = -1; switch(mFlag){ case FLAG_WAV: AudioRecordFunc mRecord_1 = AudioRecordFunc.getInstance(); mResult = mRecord_1.startRecordAndFile(); break; case FLAG_AMR: MediaRecordFunc mRecord_2 = MediaRecordFunc.getInstance(); mResult = mRecord_2.startRecordAndFile(); break; } if(mResult == ErrorCode.SUCCESS){ uiThread = new UIThread(); new Thread(uiThread).start(); mState = mFlag; }else{ Message msg = new Message(); Bundle b = new Bundle();// 存放数据 b.putInt("cmd",CMD_RECORDFAIL); b.putInt("msg", mResult); msg.setData(b); uiHandler.sendMessage(msg); // 向Handler发送消息,更新UI } } /** * 停止录音 */ private void stop(){ if(mState != -1){ switch(mState){ case FLAG_WAV: AudioRecordFunc mRecord_1 = AudioRecordFunc.getInstance(); mRecord_1.stopRecordAndFile(); break; case FLAG_AMR: MediaRecordFunc mRecord_2 = MediaRecordFunc.getInstance(); mRecord_2.stopRecordAndFile(); break; } if(uiThread != null){ uiThread.stopThread(); } if(uiHandler != null) uiHandler.removeCallbacks(uiThread); Message msg = new Message(); Bundle b = new Bundle();// 存放数据 b.putInt("cmd",CMD_STOP); b.putInt("msg", mState); msg.setData(b); uiHandler.sendMessageDelayed(msg,1000); // 向Handler发送消息,更新UI mState = -1; } } private final static int CMD_RECORDING_TIME = 2000; private final static int CMD_RECORDFAIL = 2001; private final static int CMD_STOP = 2002; class UIHandler extends Handler{ public UIHandler() { } @Override public void handleMessage(Message msg) { // TODO Auto-generated method stub Log.d("MyHandler", "handleMessage......"); super.handleMessage(msg); Bundle b = msg.getData(); int vCmd = b.getInt("cmd"); switch(vCmd) { case CMD_RECORDING_TIME: int vTime = b.getInt("msg"); MainActivity.this.txt.setText("正在录音中，已录制："+vTime+" s"); break; case CMD_RECORDFAIL: int vErrorCode = b.getInt("msg"); String vMsg = ErrorCode.getErrorInfo(MainActivity.this, vErrorCode); MainActivity.this.txt.setText("录音失败："+vMsg); break; case CMD_STOP: int vFileType = b.getInt("msg"); switch(vFileType){ case FLAG_WAV: AudioRecordFunc mRecord_1 = AudioRecordFunc.getInstance(); long mSize = mRecord_1.getRecordFileSize(); MainActivity.this.txt.setText("录音已停止.录音文件:"+AudioFileFunc.getWavFilePath()+"
文件大小："+mSize); break; case FLAG_AMR: MediaRecordFunc mRecord_2 = MediaRecordFunc.getInstance(); mSize = mRecord_2.getRecordFileSize(); MainActivity.this.txt.setText("录音已停止.录音文件:"+AudioFileFunc.getAMRFilePath()+"
文件大小："+mSize); break; } break; default: break; } } }; class UIThread implements Runnable { int mTimeMill = 0; boolean vRun = true; public void stopThread(){ vRun = false; } public void run() { while(vRun){ try { Thread.sleep(1000); } catch (InterruptedException e) { // TODO Auto-generated catch block e.printStackTrace(); } mTimeMill ++; Log.d("thread", "mThread........"+mTimeMill); Message msg = new Message(); Bundle b = new Bundle();// 存放数据 b.putInt("cmd",CMD_RECORDING_TIME); b.putInt("msg", mTimeMill); msg.setData(b); MainActivity.this.uiHandler.sendMessage(msg); // 向Handler发送消息,更新UI } } } } |
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