Android 录音AudioRecord

AudioRecord是安卓多媒体框架中用于录制音频的工具。它支持录制原始音频数据，即PCM数据，PCM数据不能被播放器直接播放，需要编码压缩成常见音频格式才能被播放器识别。通常生成PCM文件之后可将PCM文件转成WAV文件一般的播放器便可直接播放了。

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接下来处理AudioRecord操作。

1.初始化AudioRecord

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先了解几个概念：

audioSource：音频来源sampleRateInHz：采样率，以赫兹为单位。目前，只有44100Hz是保证在所有设备上都可以使用的速率(最适合人耳的)，但是其他速率（例如22050、16000和11025）可能在某些设备上可以使用；如果用于语音识别的话根据不同厂商需要采用不同的采样率channelConfig：音频通道的配置audioFormat：音频数据的格式bufferSizeInBytes：在录制期间写入音频数据的缓冲区的总大小（以字节为单位）

初始化操作：

int mBufferSize = AudioRecord.getMinBufferSize(16000, AudioFormat.CHANNEL_IN_MONO, AudioFormat.ENCODING_PCM_16BIT)*2;AudioRecord mAudioRecord = new AudioRecord(MediaRecorder.AudioSource.MIC,        16000,        AudioFormat.CHANNEL_IN_MONO,//双声道        AudioFormat.ENCODING_PCM_16BIT,        mBufferSize);

 2.开始录音

 /**     * 录制pcm文件     * @param pcmFilePath pcm文件路径     */    public void startRecord(String pcmFilePath) {        if (isRecord) {            return;        }        this.mPcmFilePath=pcmFilePath;        isRecord = true;        RecordThread recordThread = new RecordThread();        mExecutorService.execute(recordThread);    } class RecordThread implements Runnable {        @Override        public void run() {            mAudioRecord.startRecording();            FileOutputStream fos = null;            try {                Log.i(TAG, "文件地址: " + mPcmFilePath);                fos = new FileOutputStream(mPcmFilePath);                byte[] bytes = new byte[mBufferSize];                while (isRecord) {                    mAudioRecord.read(bytes, 0, bytes.length);                    fos.write(bytes, 0, bytes.length);                    fos.flush();                }                Log.i(TAG, "停止录制");                mAudioRecord.stop();                fos.flush();            } catch (IOException e) {                e.printStackTrace();            } finally {                if (fos != null) {                    try {                        fos.close();                    } catch (IOException e) {                        e.printStackTrace();                    }                }            }        }    }

3.结束录音

/**     * 停止录制     */    public void stopRecord() {        isRecord = false;    }

4.将录音生成的pcm文件转成wav文件

/**     * pcm文件转wav文件     * @param pcmFile pcm文件     * @param wavFile wav文件     */    public void pcm2Wav(File pcmFile, File wavFile) {        if (!pcmFile.exists()){            throw new RuntimeException(pcmFile.getAbsolutePath()+",there is no pcm file");        }        mExecutorService.execute(new PcmToWavThread(pcmFile,wavFile));    }    class PcmToWavThread implements Runnable {        File pcmFile;        File wavFile;        public PcmToWavThread(File pcmFile, File wavFile) {            this.pcmFile = pcmFile;            this.wavFile = wavFile;        }        @Override        public void run() {            if (!wavFile.exists()){                try {                    wavFile.createNewFile();                    PcmToWavUtil util=new PcmToWavUtil(mSampleRate,mChannel,mFormat);                    util.pcmToWav(pcmFile.getAbsolutePath(),wavFile.getAbsolutePath());                } catch (IOException e) {                    e.printStackTrace();                }            }        }    }

 pcm文成wav文件方法如下：

/**     * pcm文件转wav文件     *     * @param inFilename 源文件路径     * @param outFilename 目标文件路径     */    public void pcmToWav(String inFilename, String outFilename) {        FileInputStream in;        FileOutputStream out;        long totalAudioLen;//总录音长度        long totalDataLen;//总数据长度        long longSampleRate = mSampleRate;        int channels = mChannel == AudioFormat.CHANNEL_IN_MONO ? 1 : 2;        long byteRate = 16 * mSampleRate * channels / 8;        byte[] data = new byte[mBufferSize];        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);                out.flush();            }            Log.e(TAG, "pcmToWav: 停止处理");            in.close();            out.close();        } catch (IOException e) {            e.printStackTrace();        }    }    /**     * 加入wav文件头     */    private void writeWaveFileHeader(FileOutputStream out, long totalAudioLen,                                     long totalDataLen, long longSampleRate, int channels, long byteRate)            throws IOException {        byte[] header = new byte[44];        // RIFF/WAVE header        header[0] = 'R';        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);        //WAVE        header[8] = 'W';        header[9] = 'A';        header[10] = 'V';        header[11] = 'E';        // 'fmt ' chunk        header[12] = 'f';        header[13] = 'm';        header[14] = 't';        header[15] = ' ';        // 4 bytes: size of 'fmt ' chunk        header[16] = 16;        header[17] = 0;        header[18] = 0;        header[19] = 0;        // format = 1        header[20] = 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);        // block align        header[32] = (byte) (2 * 16 / 8);        header[33] = 0;        // bits per sample        header[34] = 16;        header[35] = 0;        //data        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);    }

5.释放资源

/**     * 释放资源     */    public void release() {        if (mAudioRecord != null) {            mAudioRecord.release();        }        if (mExecutorService!=null){            mExecutorService.shutdown();        }    }

至此录音功能即可实现了，如果想要测试可以直接使用MediaPlayer方法进行录音播放