1.音频录制pcm录制安卓中可使用AudioRecord进行音频录制录制的结果是pcm文件也就是音频裸数据裸流。可调用AudioRecord.startRecording进行录制不过使用前需要初始化AudioRecord。Java层构造AudioRecord,参数有音频源采样率声道数采样位深缓冲区大小通过 AudioRecord.getMinBufferSize()计算所需的最小缓冲区大小。参数最终会传递给 Native 层的 AudioRecord对象并通过AudioSystem与 Android系统的音频服务 (AudioFlinger) 进行交互申请和配置音频输入资源。初始化成功后native层的AudioRecord会拿到AudioFlinger的 Binder 代理对象之后就是使用binder进行通信。1.1 音频源//位于MediaRecorder类 public final class AudioSource { public static final int CAMCORDER 5; public static final int DEFAULT 0; public static final int MIC 1; public static final int REMOTE_SUBMIX 8; public static final int UNPROCESSED 9; public static final int VOICE_CALL 4; public static final int VOICE_COMMUNICATION 7; public static final int VOICE_DOWNLINK 3; public static final int VOICE_PERFORMANCE 10; public static final int VOICE_RECOGNITION 6; public static final int VOICE_UPLINK 2; AudioSource() { throw new RuntimeException(Stub!); } }音频源主要特点典型应用场景延迟音质DEFAULT (0)​系统默认音频源行为可能因设备而异通用录音不明确要求时使用一般一般MIC (1)​主麦克风未经特殊处理普通录音、语音备忘录低较好VOICE_CALL (4)​通话上下行音频双向录制整个通话过程双方声音最低电话音质窄频VOICE_UPLINK (2)​只录制发送给对方的声音只录自己说话不录对方低电话音质VOICE_DOWNLINK (3)​只录制从对方接收的声音只录对方声音不录自己低电话音质VOICE_COMMUNICATION (7)​VoIP 通话优化有回声消除和降噪微信/QQ 语音通话、视频会议较低语音优化VOICE_RECOGNITION (6)​语音识别优化清晰化人声语音助手、语音转文字低语音清晰CAMCORDER (5)​视频录制专用通常指向后置麦克风相机 App 录像指向性更好一般立体声/环境声UNPROCESSED (9)​原始、未加工的麦克风信号专业音频处理、声学分析低最高但含噪音REMOTE_SUBMIX (8)​录制系统播放的音频不录麦克风屏幕录制、内部音频捕获低同系统输出VOICE_PERFORMANCE (10)​高性能低延迟语音处理专业音乐/实时处理应用最低高质量语音1.2 采样率代表1s内的采样次数采样率越高越接近真实音频但是占用空间越大一般的高质量音乐会使用44.1KHz或者48KHz如果只是单纯录音听个响不要求音质可用使用8KHz或者16KHz1.3 声道数即有多少个喇叭播放声音有单声道、双声道等//对应的宏定义在AudioFormat类中 public static final int CHANNEL_INVALID 0; //无效的通道配置。 public static final int CHANNEL_IN_BACK 32; //后置麦克风输入通道。 public static final int CHANNEL_IN_BACK_PROCESSED 512; //处理后的后置麦克风输入。 public static final int CHANNEL_IN_DEFAULT 1; //默认的音频输入通道通常是主麦克风。 public static final int CHANNEL_IN_FRONT 16; //前置麦克风输入通道。 public static final int CHANNEL_IN_FRONT_PROCESSED 256;//处理后的前置麦克风输入。 public static final int CHANNEL_IN_LEFT 4; //左声道输入。 public static final int CHANNEL_IN_LEFT_PROCESSED 64; //处理后的左声道输入。 public static final int CHANNEL_IN_MONO 16; //单声道输入通常与 CHANNEL_IN_FRONT相同值但含义不同。 public static final int CHANNEL_IN_PRESSURE 1024; //压力传感器输入非音频可能是用于某些特殊传感器数据。 public static final int CHANNEL_IN_RIGHT 8; //右声道输入。 public static final int CHANNEL_IN_RIGHT_PROCESSED 128;//处理后的右声道输入。 public static final int CHANNEL_IN_STEREO 12; //立体声输入左 右即 4 8。 public static final int CHANNEL_IN_VOICE_DNLINK 32768; //下行语音通道例如通话时的听筒输入。 public static final int CHANNEL_IN_VOICE_UPLINK 16384; //上行语音通道例如通话时的麦克风输入。 public static final int CHANNEL_IN_X_AXIS 2048; //X轴运动传感器输入例如加速度计。 public static final int CHANNEL_IN_Y_AXIS 4096; //Y轴运动传感器输入。 public static final int CHANNEL_IN_Z_AXIS 8192; //Z轴运动传感器输入。1.4 采样位深一次采样数据使用多少个bit存放//宏定义位于AudioFormat中 public static final int ENCODING_PCM_16BIT 2; //16bit public static final int ENCODING_PCM_24BIT_PACKED 21; //24bit public static final int ENCODING_PCM_32BIT 22; //32bit public static final int ENCODING_PCM_8BIT 3; //8bit public static final int ENCODING_PCM_FLOAT 4; //32位浮点数1.5 示例代码public class MicroPhoneRecorder { private static String TAG MicroPhoneRecoder; private int mFrequency 8000; private int mChannel AudioFormat.CHANNEL_IN_MONO; private int mSampleBit AudioFormat.ENCODING_PCM_16BIT; private String mSavePath; private AudioRecord mAudioRecorder; private byte[] mBuffers null; private boolean isInit false; private boolean mIsRecording false; public MicroPhoneRecorder(int freq, int channel, int sampleBit, String savePath) { Log.d(TAG, MicroPhoneRecorder() called with: freq [ freq ] , channel [ channel ] , sampleBit [ sampleBit ] , savePath [ savePath ]); mFrequency freq; mChannel channel; mSampleBit sampleBit; mSavePath savePath; init(); } SuppressLint(MissingPermission) private void init() { //使用前需要获取音频录制权限 permission.RECORD_AUDIO if (!isInit) { int size AudioRecord.getMinBufferSize(mFrequency, mChannel, mSampleBit); mBuffers new byte[size * 4]; //如果没权限audioRecord创建会有问题后面startRecording会抛异常 mAudioRecorder new AudioRecord(MediaRecorder.AudioSource.MIC, mFrequency, mChannel, mSampleBit, size); isInit true; } } public void setSavePath(String path) { mSavePath path; } public void release() { Log.d(TAG, recorder release); mAudioRecorder.release(); mAudioRecorder null; } public boolean StartRecord() { Log.d(TAG, StartRecord); boolean result false; if (mAudioRecorder ! null) { try { mIsRecording true; //读取从AudioRecord读取pcm数据写入文件 new Thread(new Runnable() { Override public void run() { int nDataRead 0; DataOutputStream mDataOutputStream null; //注如果使用的文件存储目录不是app私有目录需要申请存储权限 try { mDataOutputStream new DataOutputStream(new BufferedOutputStream(new FileOutputStream( mSavePath, true))); } catch (Exception e) { Log.d(TAG, mDataOutputStream create fail Exception e); } while (mIsRecording) { if (mAudioRecorder.getState() AudioRecord.STATE_INITIALIZED) { Arrays.fill(mBuffers, (byte) 0); try { nDataRead mAudioRecorder.read(mBuffers, 0, mBuffers.length); } catch (Exception e) { nDataRead 0; } if (nDataRead 0) { try { // 将采集到的PCM数据写入文件 if (mDataOutputStream ! null) { mDataOutputStream.write(mBuffers, 0, nDataRead); } } catch (Exception e) { Log.e(TAG, pcm data write fail Exception e); } } } else { //AudioRecord未初始化完等待50ms try { Thread.sleep(50); } catch (InterruptedException e) { } } } if (mDataOutputStream ! null) { try { mDataOutputStream.close(); mDataOutputStream null; } catch (IOException e) { Log.e(TAG, mDataOutputStream close fail IOException e); } } } }, recorder work thread).start(); mAudioRecorder.startRecording(); result true; Log.d(TAG, recording...); } catch (Exception e) { mIsRecording false; Log.i(TAG, StartRecord: Exception e.toString()); } } else { Log.i(TAG, StartRecord: mAudioRecorder null); } return result; } public void StopRecord() { Log.d(TAG, StopRecord); if (mAudioRecorder ! null) { mAudioRecorder.stop(); } mIsRecording false; } public boolean isInitialized() { if (mAudioRecorder null) { Log.i(TAG, isInitialized: mAudioRecorder null); } else { Log.i(TAG, isInitialized: state mAudioRecorder.getState()); } return mAudioRecorder ! null mAudioRecorder.getState() ! AudioRecord.STATE_UNINITIALIZED; } }使用示例MicroPhoneRecorder microPhoneRecorder; public void startRecord() { //app私有目录 不需要存储权限 File file new File(getContext().getFilesDir(), temp.pcm); if (file.exists()) { file.delete(); } //记得获取录音权限 microPhoneRecorder new MicroPhoneRecorder( 8000, AudioFormat.CHANNEL_IN_MONO, AudioFormat.ENCODING_PCM_16BIT, file.getPath() ); boolean result microPhoneRecorder.StartRecord(); Log.d(TAG, result result); } public void stopRecord() { microPhoneRecorder.StopRecord(); } public void releaseRecorder() { microPhoneRecorder.release(); }2.音频试听pcm播放安卓中可以使用AudioTrack进行pcm的播放但是此类不支持解码所以不能播放mp3等编码后的音频。AudioTrack它是Audio系统对外提供的APIMediaPlayer在播放音乐时最终用到的也是它它是最基本的音频数据输出类。在java层构造函数需要传音频流类型采样率声道数缓冲区大小数据加载模式。2.1 音频流类型一般用music即可//宏定义位于AudioManager public static final int STREAM_ACCESSIBILITY 10; public static final int STREAM_ALARM 4; public static final int STREAM_DTMF 8; public static final int STREAM_MUSIC 3; public static final int STREAM_NOTIFICATION 5; public static final int STREAM_RING 2; public static final int STREAM_SYSTEM 1; public static final int STREAM_VOICE_CALL 0;流类型常量值用途说明音量控制特点STREAM_VOICE_CALL​0语音通话通话音量最高优先级通话时其他音频会被暂停/降低STREAM_SYSTEM​1系统声音系统音量按键音、锁屏音、UI反馈音STREAM_RING​2来电铃声铃声音量来电、消息铃声STREAM_MUSIC​3媒体播放媒体音量最常用音乐、视频、游戏音效STREAM_ALARM​4闹钟闹钟音量优先级高即使静音也会响STREAM_NOTIFICATION​5通知音通知音量短信、推送通知声音STREAM_DTMF​8拨号音DTMF音量电话拨号键盘音0-9, *, #STREAM_ACCESSIBILITY​10无障碍媒体音量屏幕阅读器等API 262.2 加载模式其中加载模式有流式和静态。流式通过write一次次把音频数据写到AudioTrack中也就是先写进去多少AudioTrack就播放多少后面再继续写继续播放这种工作方式由于每次都需要把数据从用户提供的Buffer中拷贝到AudioTrack内部的Buffer中这在一定程度上会引起延时静态在播放之前就把所有的数据通过一次write调用传递到AudioTrack的内部缓冲区中后续就不必再传递数据了。基于此区别流式适合长音频、实时音频、占用内存空间小但是延迟较高静态适合短音频延迟较低占用空间较多。//宏定义位于AudioTrack类中 public static final int MODE_STATIC 0; //静态 public static final int MODE_STREAM 1; //流式2.3 示例代码public class PcmPlayer { private static String TAG PcmPlayer; private int mChannel AudioFormat.CHANNEL_OUT_MONO; private int mSampleBit AudioFormat.ENCODING_PCM_16BIT; private int mFrequency 8000; private String mFilePath; private AudioTrack audioTrack; private int mPausePosition 0; //暂停的位置 private FileInputStream fileInputStream null; //播放文件的输入流 public PcmPlayer( String filePath, int frequency, int channel, int sampleBit) { Log.d(TAG, PcmPlayer call with filePath[ filePath ] , frequency[ frequency ] , channel[ channel ] , sampleBit[ sampleBit ]); mFilePath filePath; mFrequency frequency; mChannel channel; mSampleBit sampleBit; init(); } private void init() { int minBufSize AudioTrack.getMinBufferSize(mFrequency, mChannel, mSampleBit); audioTrack new AudioTrack( AudioManager.STREAM_MUSIC, mFrequency, mChannel, mSampleBit, minBufSize * 4, AudioTrack.MODE_STREAM ); //如果使用static加载模式buffer至少要能存储整个pcm文件 } //修改要播放的文件路径 public void setFilePath(String filePath) { mFilePath filePath; } //播放pcm public void playPcm(){ Thread playThrad new Thread(new Runnable() { Override public void run() { Log.d(TAG, playPcm); if (audioTrack null) { Log.d(TAG, audioTrack null); return; } try { //如果不是app私有目录需要先获取存储权限 File recordFile new File(mFilePath); if (!recordFile.exists()) { Log.e(TAG, file not exist); audioTrack.stop(); return; } //如果是暂停状态不重新创建文件流因为需要恢复播放 if (audioTrack.getPlayState() ! AudioTrack.PLAYSTATE_PAUSED) { fileInputStream new FileInputStream(recordFile); } byte[] buffer new byte[1024]; // 使用合适的缓冲区大小 int bytesRead; audioTrack.play(); // 读取并播放PCM数据 while (audioTrack.getPlayState() AudioTrack.PLAYSTATE_PLAYING (bytesRead fileInputStream.read(buffer)) 0) { audioTrack.write(buffer, 0, bytesRead); // 直接播放读取的数据 } Log.d(TAG, audioTrack.getPlayState() audioTrack.getPlayState()); if (audioTrack.getPlayState() AudioTrack.PLAYSTATE_PLAYING) { LogUtil.d(TAG, 正常播放完没有被外部取消); fileInputStream.close(); fileInputStream null; //listener.onfinished(); //如果需要在播放后执行一些逻辑可以setListener进来 } else if (audioTrack.getPlayState() AudioTrack.PLAYSTATE_STOPPED) { LogUtil.d(TAG, 外部停止播放); fileInputStream.close(); fileInputStream null; //listener.onStop(); } else if (audioTrack.getPlayState() AudioTrack.PLAYSTATE_PAUSED) { LogUtil.d(TAG, 外部暂停播放); //listener.onPause(); } } catch (IOException e) { Log.e(TAG, FileInputStream fail IOException e); } } }, pcmPlayer thread); playThrad.start(); } //停止pcm播放,下次调用playPcm时从头开始播 public void stopPcm() { Log.d(TAG, stopPcm); if (audioTrack ! null) { audioTrack.stop(); mPausePosition 0; try { if (fileInputStream ! null) { fileInputStream.close(); fileInputStream null; } } catch (IOException e) { Log.e(TAG, fileInputStream.close fail IOException e); } } } //暂停播放pcm, 下次调用playPcm时从暂停地方继续 public void pausePcm() { Log.d(TAG, pausePcm); if (audioTrack ! null) { audioTrack.pause(); mPausePosition audioTrack.getPlaybackHeadPosition(); Log.d(TAG, mPausePosition mPausePosition); } } //释放资源 public void releasePlayer() { Log.d(TAG, releasePlayer); if (audioTrack ! null) { audioTrack.stop(); audioTrack.release(); audioTrack null; try { if (fileInputStream ! null) { fileInputStream.close(); fileInputStream null; } } catch (IOException e) { Log.e(TAG, fileInputStream.close fail IOException e); } } } //设置播放结束的listener // public void setListener(Listener listener) { // // } }使用示例PcmPlayer pcmPlayer; //播放pcm public void startPlayPcm() { //app私有目录 不需要存储权限 File file new File(getContext().getFilesDir(), temp.pcm); pcmPlayer new PcmPlayer(file.getPath(), 8000, AudioFormat.CHANNEL_OUT_MONO, AudioFormat.ENCODING_PCM_16BIT); pcmPlayer.playPcm(); } //暂停 public void pausePcm() { pcmPlayer.pausePcm(); } //停止播放 public void stopPcm() { pcmPlayer.stopPcm(); } //恢复播放, 如果之前是停止播放那么这里从头开始播放 public void resumePcm() { pcmPlayer.playPcm(); } //释放资源 public void releasePlayer() { pcmPlayer.releasePlayer(); }3. 音频试听mp3等编码格式播放播放已经编码的音频文件需要播放器支持解码一般使用MediaPlayer即可MediaPlayer支持播放视频和音频可以自动识别文件类型解码支持网络流播放。使用MediaPlayer需要注意状态的变化特别是涉及暂停恢复重新播放切换文件等因为MediaPlayer使用状态机实现状态不对的话会抛异常3.1 示例代码public class AudioPlayer { private static String TAG AudioPlayer; private MediaPlayer mPlayer; private boolean isPaused false; //是否处于暂停状态 private PlayStateListener listener; //外部传入的监听器用于将播放状态通知外部调用 public interface PlayStateListener { void onPrepared(); void onCompletion(); void onError(int what, int extra); } public AudioPlayer() { mPlayer new MediaPlayer(); mPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC); // 设置音频流类型 } //设置MediaPlayer播放状态的监听器 private void initPlayerListener() { Log.d(TAG, initPlayerListener); if (mPlayer null) { Log.e(TAG, mPlayer null); return; } // 准备完成监听器 mPlayer.setOnPreparedListener(new MediaPlayer.OnPreparedListener() { Override public void onPrepared(MediaPlayer mp) { LogUtil.d(TAG, 准备完成开始播放); mp.start(); // 准备完成后开始播放 if (listener ! null) { listener.onPrepared(); //回调通知外部已经准备完成开始播放 } } }); // 播放完成监听器 mPlayer.setOnCompletionListener(new MediaPlayer.OnCompletionListener() { Override public void onCompletion(MediaPlayer mp) { LogUtil.d(TAG, 播放完成); if (listener ! null) { listener.onCompletion(); //通知外部播放完成 } } }); // 播放错误监听器 mPlayer.setOnErrorListener(new MediaPlayer.OnErrorListener() { Override public boolean onError(MediaPlayer mp, int what, int extra) { LogUtil.e(TAG, 播放发生错误); LogUtil.e(TAG, MediaPlayer error: what what , extra extra); if (listener ! null) { listener.onError(what, extra); //通知外部播放器错误 } releasePlayer(); return true; // 返回true表示错误已被处理 } }); LogUtil.d(TAG, 监听器设置完成); } //设置音频文件路径 public void setFilePath(String filePath) { Log.d(TAG, setFilePath filePath filePath); if (mPlayer null) { Log.e(TAG, mPlayer null); return; } //正在播放先停止并重置 if (mPlayer.isPlaying()) { stopPlay(); mPlayer.reset(); } //如果播放的音频不在app私有目录需要存储权限 try { mPlayer.setDataSource(filePath); // 设置音频文件路径 initPlayerListener(); //重新设置监听setDataSource监听器会被清除 isPaused false; } catch (IOException e) { Log.e(TAG, setDataSource fail IOException e); releasePlayer(); } } //设置回调用于获取播放状态 public void setPlayStateListener(PlayStateListener listener) { this.listener listener; } //开始播放 public void startPlay() { LogUtil.d(TAG, startPlay); if (mPlayer null) { Log.e(TAG, mPlayer null); return; } // 异步准备防止阻塞UI线程 mPlayer.prepareAsync(); } //停止播放 public void stopPlay() { LogUtil.d(TAG, stopPlay); if (mPlayer null) { Log.e(TAG, mPlayer null); return; } mPlayer.stop(); isPaused false; } //暂停播放 public void pausePlay() { LogUtil.d(TAG, pausePlay); if (mPlayer null) { Log.e(TAG, mPlayer null); return; } mPlayer.pause(); isPaused true; Log.d(TAG, 当前播放的时间ms mPlayer.getCurrentPosition() mPlayer.getCurrentPosition()); } //恢复播放 public void resumePlay() { LogUtil.d(TAG, resumePlay); if (mPlayer null) { Log.e(TAG, mPlayer null); return; } if (isPaused) { Log.d(TAG, 继续播放); mPlayer.start(); isPaused false; } else { Log.d(TAG, 不在暂停状态重新开始播放); startPlay(); } } //释放资源 public void releasePlayer() { LogUtil.d(TAG, releasePlayer); if (mPlayer ! null) { mPlayer.stop(); mPlayer.release(); mPlayer null; } } }使用示例AudioPlayer audioPlayer new AudioPlayer(); public void startPlayAudio() { //app私有目录 不需要存储权限 File file new File(getContext().getFilesDir(), sample.mp3); //设置播放路径 audioPlayer.setFilePath(file.getPath()); //设置播放状态监听 audioPlayer.setPlayStateListener(new AudioPlayer.PlayStateListener() { Override public void onPrepared() { //播放器准备完成开始播放了 Log.d(TAG, onPrepared 播放器准备完成开始播放了); } Override public void onCompletion() { //已经播放完成 Log.d(TAG, onCompletion 播放完成); } Override public void onError(int what, int extra) { //播放过程发生错误 Log.e(TAG, onError 播放错误 what what , extra extra); } }); //播放 audioPlayer.startPlay(); } public void stopPlayAudio() { audioPlayer.stopPlay(); } public void pasuePlayAudio() { audioPlayer.pausePlay(); } public void resumePlayAudio() { auidoPlayer.resumePlay(); } public void releasePlayer() { audioPlayer.releasePlayer(); }