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
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 | 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
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 | 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; } }} |
1 | |
3、其他文件
AudioFileFunc.java
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 | 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
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 | 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
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 | <?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
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 | 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()+"\n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()+"\n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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