Android5.1 录音机 MediaRecorder、微信 AudioRecord

 

Android提供了两个对象用于录音的实现：MediaRecorder 和AudioRecord

1.MediaRecorder：录制的音频文件是经过压缩后的，需要设置编码器 并且录制的音频文件可以用系统自带的Music播放器播放 MediaRecorder已经集成了录音、编码、压缩等，并支持少量的录音音频格式，但是这也是他的缺点，支持的格式过少并且无法实时处理音频数据
2.AudioRecord：主要实现对音频实时处理以及边录边播功能，相对MediaRecorder比较专业，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

 

一.录音机

1.1.packages\apps\SoundRecorder\src\com\android\soundrecorder\Recorder.java

mRecorder.prepare(); //准备

mRecorder.start();//开始

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public void startRecording(int outputfileformat, int recordingType,String extension, Context context) {    stop();    if (mSampleFile == null) {        String myExtension = extension + TEMP_SUFFIX;        File sampleDir = Environment.getExternalStorageDirectory();        if (!sampleDir.canWrite()) // Workaround for broken sdcard support on the device.            sampleDir = new File("/sdcard/sdcard");        String sampleDirPath = null;        if (sampleDir != null) {            sampleDirPath = sampleDir.getAbsolutePath() + File.separator                    + RECORD_FOLDER;        }        if (sampleDirPath != null) {            sampleDir = new File(sampleDirPath);        }        if (sampleDir != null && !sampleDir.exists()) {            if (!sampleDir.mkdirs()) {                Log.i(TAG, "<startRecording> make dirs fail");            }        }        try {            if (null != sampleDir) {                Log.i(TAG, "SR sampleDir  is:" + sampleDir.toString());            }            SimpleDateFormat simpleDateFormat = new SimpleDateFormat(                    "yyyyMMddHHmmss");            String time = simpleDateFormat.format(new Date(System                    .currentTimeMillis()));            StringBuilder stringBuilder = new StringBuilder();            stringBuilder.append(SAMPLE_PREFIX).append("_"+time)                    .append(myExtension);            String name = stringBuilder.toString();            mSampleFile = new File(sampleDir, name);            boolean result = mSampleFile.createNewFile();            if (result) {                Log.i(TAG, "creat file success");            }        } catch (IOException e) {            setError(SDCARD_ACCESS_ERROR);            return;        }    }         mRecorder = new MediaRecorder();    mRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);    mRecorder.setOutputFormat(outputfileformat);    mRecorder.setOutputFile(mSampleFile.getAbsolutePath());      mRecorder.setAudioSamplingRate(mSamplingRate);

1.2.frameworks\base\media\java\android\media\MediaRecorder.java

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1 2	public native void start() throws IllegalStateException; public native void stop() throws IllegalStateException;

1.3.frameworks\base\media\jni\android_media_MediaCodec.cpp

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static void android_media_MediaCodec_start(JNIEnv *env, jobject thiz) {     ALOGV("android_media_MediaCodec_start");       sp<JMediaCodec> codec = getMediaCodec(env, thiz);       if (codec == NULL) {         throwExceptionAsNecessary(env, INVALID_OPERATION);         return;     }       status_t err = codec->start();       throwExceptionAsNecessary(env, err, ACTION_CODE_FATAL, "start failed"); }   static void android_media_MediaCodec_stop(JNIEnv *env, jobject thiz) {     ALOGV("android_media_MediaCodec_stop");       sp<JMediaCodec> codec = getMediaCodec(env, thiz);       if (codec == NULL) {         throwExceptionAsNecessary(env, INVALID_OPERATION);         return;     }       status_t err = codec->stop();       throwExceptionAsNecessary(env, err); }

 二.微信

2.1.AudioRecord

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/**  * 开始录音  *  * @param listener 音频流的监听  */ public void startRecord(final RecordStreamListener listener) {       if (status == Status.STATUS_NO_READY || TextUtils.isEmpty(fileName)) {         throw new IllegalStateException("录音尚未初始化,请检查是否禁止了录音权限~");     }     if (status == Status.STATUS_START) {         throw new IllegalStateException("正在录音");     }     Log.d("AudioRecorder", "===startRecord===" + audioRecord.getState());     audioRecord.startRecording();       new Thread(new Runnable() {         @Override         public void run() {             writeDataTOFile(listener);         }     }).start(); }

2.2.frameworks\base\media\java\android\media\AudioRecord.java

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/**  * Starts recording from the AudioRecord instance.  * @throws IllegalStateException  */ public void startRecording() throws IllegalStateException {     if (mState != STATE_INITIALIZED) {         throw new IllegalStateException("startRecording() called on an "                 + "uninitialized AudioRecord.");     }       // start recording     synchronized(mRecordingStateLock) {         if (native_start(MediaSyncEvent.SYNC_EVENT_NONE, 0) == SUCCESS) {             handleFullVolumeRec(true);             mRecordingState = RECORDSTATE_RECORDING;         }         mFileObserver.startWatching();     } }   /**  * Starts recording from the AudioRecord instance when the specified synchronization event  * occurs on the specified audio session.  * @throws IllegalStateException  * @param syncEvent event that triggers the capture.  * @see MediaSyncEvent  */ public void startRecording(MediaSyncEvent syncEvent) throws IllegalStateException {     if (mState != STATE_INITIALIZED) {         throw new IllegalStateException("startRecording() called on an "                 + "uninitialized AudioRecord.");     }       // start recording     synchronized(mRecordingStateLock) {         if (native_start(syncEvent.getType(), syncEvent.getAudioSessionId()) == SUCCESS) {             handleFullVolumeRec(true);             mRecordingState = RECORDSTATE_RECORDING;         }     }     mFileObserver.startWatching(); }