AudioRecord、AudioTractor实现音频的录制和播放

前言

我们在刚学习多媒体编程的时候，接触音视频的录制时更多的是通过MediaRecorder实现音频的录制；请看我的这篇文章MediaRecorder录制音频及代码的抽取封装
实现音频的播放通过MediaPlayer；可以查看我的这篇博客MediaPlayer播放不同来源的音频文件
SoundPool更多的是播放短而急促的声音，比如：嘟一声！！！比较简单这里就不再累述；
我们可以通过AudioRecorder、AudioTractor实现录制及播放固定的采样率、声道数、音频格式；

知识结构

AudioRecorder：The AudioRecord class manages the audio resources for Java applications to record audio from the audio input hardware of the platform.（大致意思就是AudioRecord以平台的硬件录制音频）

常用方法：
1、构造方法：
AudioRecord(int audioSource, int sampleRateInHz, int channelConfig, int audioFormat, int bufferSizeInBytes)

• audioSource：声音来源；如：MediaRecorder.AudioSource.MIC
• sampleRateInHz：声音采样率
• audioFormat：声音的格式
• bufferSizeInBytes：缓存大小；常通过bufferSizeInBytes = AudioRecord.getMinBufferSize(sampleRateInHz,
• channelConfig, audioFormat);求得缓存大小

2、公共方法：
startRecording()：开始录制

read(short[] audioData, int offsetInShorts, int sizeInShorts) Reads audio data from the audio hardware for recording into a buffer.

• audioData ：short类型的缓存
• offsetInShorts ：偏移量
• int sizeInShorts ： 需要读取的大小

stop()停止录制

---

AudioTractor：The AudioTrack class manages and plays a single audio resource for Java applications（大致意思：管理和播放应用中的音频资源）

常用方法：
1、构造函数：
AudioTrack(int streamType, int sampleRateInHz, int channelConfig, int audioFormat, int bufferSizeInBytes, int mode)

• streamType：播放音频类型；可以设置为AudioManager.STREAM_MUSIC
• sampleRateInHz、channelConfig、audioFormat这三个参数与上面的AudioRecord设置相同
• bufferSizeInBytes：通过bufferSizePlay = AudioTrack.getMinBufferSize(sampleRateInHz,channelConfig, audioFormat)获得；

2、公共方法

play()：开始播放

pause()：暂停

write(short[] audioData, int offsetInShorts, int sizeInShorts)：Writes the audio data to the audio hardware for playback.（大致意思：把音频数据写入到audioData中让 audio hardware 回放）

stop()：停止

示例代码

package com.example.audiorecorderdemo.utils;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;

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.AsyncTask;
import android.os.Bundle;
import android.os.Environment;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.Toast;

import com.example.audiorecorderdemo.R;
import com.example.audiorecorderdemo.R.id;
import com.example.audiorecorderdemo.R.layout;

public class Main02Activity extends Activity implements OnClickListener{
    private Button bt_startAuduio;
    private Button bt_stopAudio;
    private Button bt_startPlay;
    private Button bt_stopPlay;
    private AudioRecord mAudioRecord;
    private AudioRecordAsyncTask mAudioRecordAsyncTask;
    private AudioStartAsyncTask mAudioStartAsyncTask;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initView();
    }

    private void initView() {
        bt_startAuduio = (Button) this.findViewById(R.id.startAudio);
        bt_stopAudio = (Button) this.findViewById(R.id.stopAudio);
        bt_startPlay = (Button) this.findViewById(R.id.startPlay);
        bt_stopPlay = (Button) this.findViewById(R.id.stopPlay);
        bt_startPlay.setOnClickListener(this);
        bt_stopPlay.setOnClickListener(this);
        bt_startAuduio.setOnClickListener(this);
        bt_stopAudio.setOnClickListener(this);
    }

    @Override
    public void onClick(View v) {
        switch (v.getId()) {
        case R.id.startAudio:
            mAudioRecordAsyncTask = new AudioRecordAsyncTask();
            mAudioRecordAsyncTask.execute();
            bt_startAuduio.setEnabled(false);
            break;
        case R.id.stopAudio:
            isAudioRecording = false;
            bt_startAuduio.setEnabled(true);
            break;
        case R.id.startPlay:
            mAudioStartAsyncTask = new AudioStartAsyncTask();
            mAudioStartAsyncTask.execute();
            break;
        case R.id.stopPlay:
            isPlay = false;
            break;
        default:
            break;
        }
    }

    private boolean isAudioRecording = false;
    private int sampleRateInHz = 8000;
    private int channelConfig = AudioFormat.CHANNEL_CONFIGURATION_MONO;
    private int audioFormat = AudioFormat.ENCODING_PCM_16BIT;
    private int bufferSizeInBytes;

    private void prepareStartRecordAudio() {
        bufferSizeInBytes = AudioRecord.getMinBufferSize(sampleRateInHz,
                channelConfig, audioFormat);
        mAudioRecord = new AudioRecord(MediaRecorder.AudioSource.MIC,
                sampleRateInHz, channelConfig, audioFormat, bufferSizeInBytes);
        // createAudioRecord();
        mAudioRecord.startRecording();
        isAudioRecording = true;
    }

    private File audioFile;

    private class AudioRecordAsyncTask extends AsyncTask<Void, Void, String> {

        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            prepareStartRecordAudio();
        }

        @Override
        protected String doInBackground(Void... params) {
            String result = null;
            try {
                // 获取录制视频保存的文件
                audioFile = new File(Environment.getExternalStorageDirectory(),
                        "/audiodatas/files/audioRecord.pcm");
                if (!audioFile.exists()) {
                    audioFile.getParentFile().mkdirs();
                }
                DataOutputStream audioOutputStream = new DataOutputStream(
                        new BufferedOutputStream(
                                new FileOutputStream(audioFile)));
                // 建立一个AudioRecorder读入数据的缓冲区
                short[] buffer = new short[bufferSizeInBytes / 4];

                while (isAudioRecording) {
                    int readResult = mAudioRecord
                            .read(buffer, 0, buffer.length);
                    for (int i = 0; i < readResult; i++) {
                        audioOutputStream.writeShort(buffer[i]);
                    }
                }

                audioOutputStream.close();
                mAudioRecord.stop();
                result = "audio record end !!!";

            } catch (Exception e) {
                result = "sudio record exception !";
            }
            return result;
        }

        @Override
        protected void onPostExecute(String result) {
            super.onPostExecute(result);
            Toast.makeText(Main02Activity.this, result, Toast.LENGTH_LONG).show();
        }
    }

    private void createAudioRecord() {
        for (int sampleRate : new int[] { 44100, 8000, 11025, 16000, 22050,
                32000, 47250, 48000 }) {
            for (short audioFormat : new short[] {
                    AudioFormat.ENCODING_PCM_16BIT,
                    AudioFormat.ENCODING_PCM_8BIT }) {
                for (short channelConfig : new short[] {
                        AudioFormat.CHANNEL_IN_MONO,
                        AudioFormat.CHANNEL_IN_STEREO }) {

                    // Try to initialize
                    try {
                        bufferSizeInBytes = AudioRecord.getMinBufferSize(
                                sampleRate, channelConfig, audioFormat);

                        if (bufferSizeInBytes < 0) {
                            continue;
                        }

                        mAudioRecord = new AudioRecord(
                                MediaRecorder.AudioSource.MIC, sampleRate,
                                channelConfig, audioFormat, bufferSizeInBytes);

                        if (mAudioRecord.getState() == AudioRecord.STATE_INITIALIZED) {

                            return;
                        }

                        mAudioRecord.release();
                        mAudioRecord = null;
                    } catch (Exception e) {
                        // Do nothing
                    }
                }
            }
        }

        throw new IllegalStateException(
                "getInstance() failed : no suitable audio configurations on this device.");
    }

    private AudioTrack mAudioTrack;
    private int bufferSizePlay;
    private boolean isPlay = false;

    public void prepareStartingAudio() {
        bufferSizePlay = AudioTrack.getMinBufferSize(sampleRateInHz,channelConfig, audioFormat);
        mAudioTrack = new AudioTrack(AudioManager.STREAM_MUSIC, sampleRateInHz,
                channelConfig, audioFormat, bufferSizePlay,
                AudioTrack.MODE_STREAM);
        mAudioTrack.play();
        isPlay = true;
    }

    public class AudioStartAsyncTask extends AsyncTask<Void, Void, String> {

        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            prepareStartingAudio();
        }

        @Override
        protected String doInBackground(Void... params) {
            String result = null;
            try {
                DataInputStream fileInput = new DataInputStream(
                        new BufferedInputStream(new FileInputStream(audioFile)));
                short[] buffer = new short[bufferSizePlay / 4];
                while (isPlay && fileInput.available() > 0) {
                    for (int i = 0; fileInput.available() > 0
                            && i < buffer.length; i++) {
                        buffer[i] = fileInput.readShort();
                    }
                    mAudioTrack.write(buffer, 0, buffer.length);
                }

                mAudioTrack.stop();
                fileInput.close();
                result = "success";
            } catch (Exception e) {
                e.printStackTrace();
                result = "fail ";
            }
            return result;
        }

        @Override
        protected void onPostExecute(String result) {
            Toast.makeText(Main02Activity.this, result, Toast.LENGTH_LONG).show();
            super.onPostExecute(result);
        }

    }
}

我把上面的代码给整理抽取了一个封装类，想看可以在这里下载：AudioRecord/AudioTractorDemo