AudioRecord

AudioRecord简介

1.AudioRecord与MediaRecorder一样用来录制音频的
2.AudioRecord可以对录制的数据进行实时的处理，比如降噪，除杂，或者将音频进行实时传输，比如IP电话，对讲功能等操作。
3.AudioRecord比MediaRecorder更接近底层，录制的音频是PCM格式的，只能用AudioTraker进行播放，或者将PCM数据转换成ａｍｒ,wav等格式播放。

AudioRecord使用

AudioRecord以pulling方式通过read()方法对缓冲区的数据进行轮询，来实时的获取缓冲区的数据。
下面来看如何使用：

// 读取数据流  返回int,读取到的字节数public int read (byte[] audioData, int offsetInBytes, int sizeInBytes)public int read (float[] audioData, int offsetInFloats, int sizeInFloats, int readMode)public int read (ByteBuffer audioBuffer, int sizeInBytes, int readMode)// 构造方法public AudioRecord (int audioSource, int sampleRateInHz, int channelConfig, int audioFormat, int bufferSizeInBytes)    audioSource：VOICE_CALL，VOICE_COMMUNICATION。。。。    sampleRateInHz  44100，22050，16000    channelConfig   CHANNEL_IN_MONO and CHANNEL_IN_STEREO    audioFormat ENCODING_PCM_8BIT ENCODING_PCM_16BIT ENCODING_PCM_FLOAT.    bufferSizeInBytes   由getMinBufferSize(int, int, int)决定// 获取成功创建AudioRecord 的最小缓冲区的大小public static int getMinBufferSize (int sampleRateInHz, int channelConfig, int audioFormat)

AudioTrack

说了录音，那么播放就得说到AudioTrack，专门用来播放PCM数据.

下面是录制与播放的代码，时间太晚了，还没有测试。

package com.asia.pcm2amr;import java.io.File;import java.io.FileInputStream;import java.io.FileOutputStream;import android.annotation.TargetApi;import android.app.Activity;import android.media.AudioFormat;import android.media.AudioManager;import android.media.AudioRecord;import android.media.AudioTrack;import android.media.MediaRecorder;import android.os.Build;import android.os.Bundle;import android.os.Environment;@TargetApi(Build.VERSION_CODES.JELLY_BEAN)public class AudioTest {    static String mPath = Environment.getExternalStorageDirectory()            .getAbsolutePath() + "/AAA/";    private AudioRecord mAudioRecord;    private AudioTrack mAudioTrack;    private boolean mIsAudioing = false;    private boolean mIsPlaying = false;    private int mMinBufferSize;    private int mRecordTime = 20;    private int mFileCount = 10;    private static AudioTest mAudioTest;    public static AudioTest getInstance() {        if (mAudioTest == null) {            mAudioTest = new AudioTest();        }        return mAudioTest;    }    public void createObject(int sampleRateInHz) {        int audioSource = MediaRecorder.AudioSource.VOICE_COMMUNICATION;        int channelConfig = AudioFormat.CHANNEL_IN_STEREO;        int audioEncoding = AudioFormat.ENCODING_PCM_16BIT;        mMinBufferSize = AudioRecord.getMinBufferSize(sampleRateInHz,                channelConfig, audioEncoding);        int bufferSizeInBytes = mMinBufferSize * 2;        mAudioRecord = new AudioRecord(audioSource, sampleRateInHz,                channelConfig, audioEncoding, bufferSizeInBytes);        int playBufSize = AudioTrack.getMinBufferSize(sampleRateInHz,                channelConfig, audioEncoding);        mAudioTrack = new AudioTrack(AudioManager.STREAM_VOICE_CALL,                sampleRateInHz, channelConfig, audioEncoding, playBufSize,                AudioTrack.MODE_STREAM, mAudioRecord.getAudioSessionId());    }    public boolean isInitSucces() {        boolean initRecorder = mAudioRecord != null                && mAudioRecord.getState() == AudioRecord.STATE_INITIALIZED;        boolean initPlayer = mAudioTrack != null                && mAudioTrack.getState() == AudioTrack.STATE_INITIALIZED;        return initRecorder && initPlayer;    }    public void startAudio() {        mIsAudioing = true;        new AudioThread(++mFileCount + ".pcm").start();    }    public void stopAudio() {        mIsAudioing = false;        if (mAudioRecord.getRecordingState() == AudioRecord.RECORDSTATE_RECORDING) {            mAudioRecord.stop();        }    }    public void startPlayer() {        mIsPlaying = true;        new PlayThread().start();    }    public void stopPlayer() {        mIsPlaying = false;        if (mAudioTrack.getPlayState() == AudioTrack.PLAYSTATE_PLAYING) {            mAudioTrack.stop();        }    }    /**     * 结束录音与播放     */    public void stopVoice() {        stopAudio();        stopPlayer();        mAudioRecord.release();        mAudioRecord = null;        mAudioTrack.release();        mAudioTrack = null;    }    private class PlayThread extends Thread {        public void run() {            try {                android.os.Process                        .setThreadPriority(android.os.Process.THREAD_PRIORITY_URGENT_AUDIO);            } catch (Exception e) {            }            try {                 File file = new File(mPath, 15 + ".pcm");                FileInputStream inputStream = new FileInputStream(file);                byte[] audioData = new byte[mMinBufferSize];                mAudioTrack.play();                while (mIsPlaying) {                    // 数据源                    int read = inputStream.read(audioData, 0, mMinBufferSize);                    mAudioTrack.write(audioData, 0, read);                }                inputStream.close();                mAudioTrack.stop();            } catch (Exception e) {            }        }    }    private class AudioThread extends Thread {        String fileName;        public AudioThread(String fileName) {            this.fileName = fileName;        }        @Override        public void run() {            try {                android.os.Process                        .setThreadPriority(android.os.Process.THREAD_PRIORITY_URGENT_AUDIO);            } catch (Exception e) {            }            try {                mAudioRecord.startRecording();                byte[] buffer = new byte[mMinBufferSize];                File file = new File(mPath, "" + fileName);                FileOutputStream outputStream = new FileOutputStream(file);                while (mIsAudioing) {                    int read = mAudioRecord.read(buffer, 0, mMinBufferSize);                    for (int i = 0; i < read; i++) {                        byte b = buffer[i];                        // 写到文件                        outputStream.write(buffer, 0, read);                    }                }                mAudioRecord.stop();                outputStream.flush();                outputStream.close();            } catch (Exception e) {                e.printStackTrace();            }        };    }}