android语音录制和压缩

   因为上一篇博客代码有点太多，就单开了，这两天主要在看android语音录制和压缩转码相关知识，前端时间看见腾讯官方微博宣布，已经开放出即使聊天软件正在等待审批，但这个直接影响电话运营商，能通过的可能性应该不大，但我对这方面的技术很有兴趣，所以就试试看。其中涉及到很多声音方面的处理问题，在android中有两个类可以录制语音：AudioRecord和MediaRecorder，MediaRecorder主要是录制音频并写入文件，而AudioRecord主要是录制音频流，录制的音频流为pcm格式，关于pcm格式可以自行搜索一下，在传输过程中可以转换为amr格式，但没有相关可以类库有点麻烦，另外iphone不支持播放amr格式音频，如果需要跨两个平台可以使用AAC，压缩比也不错，音质也很好，我还没有测试过，网上评议而已。编码方面大家都推荐speex，我看了一下，需要是用System.loadLibrary加载进speex提供的类库。下面记录一下写的一个边录制边播放的一段代码吧：
View Code JAVA
package voice.hcent.com;

import java.io.IOException;

import android.app.Activity;
import android.os.Bundle;
import android.os.Looper;
import android.os.Process;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;

import android.media.AudioFormat;
import android.media.AudioManager;
import android.media.AudioRecord;
import android.media.AudioTrack;
import android.media.MediaRecorder;

public class VoiceHcentActivity extends Activity {

    static {
        System.loadLibrary("media_jni");
    }

    public int frequency = 8000;
    private int rBufferSize, pBufferSize;
    private Button startSpeech;
    private AudioRecord recorder;
    private VoiceSpeech vspeech;
    private AudioTrack player;
    private boolean stopSpeech = false;

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        init();

        test();
    }

    public void init(){
        try{
            startSpeech = (Button)findViewById(R.id.StartSpeech);

            //设置播放器缓冲区大小
            pBufferSize = AudioTrack.getMinBufferSize(frequency, AudioFormat.CHANNEL_CONFIGURATION_MONO,
                    AudioFormat.ENCODING_PCM_16BIT);

            //获取播放器对象
            player = new AudioTrack(AudioManager.STREAM_MUSIC, frequency,
                    AudioFormat.CHANNEL_CONFIGURATION_MONO, AudioFormat.ENCODING_PCM_16BIT,
                    pBufferSize, AudioTrack.MODE_STREAM);

            //设置录音缓冲区大小
            rBufferSize = AudioRecord.getMinBufferSize(frequency,
                    AudioFormat.CHANNEL_CONFIGURATION_MONO, AudioFormat.ENCODING_PCM_16BIT);

            //获取录音机对象
            recorder = new AudioRecord(MediaRecorder.AudioSource.MIC,
                    frequency, AudioFormat.CHANNEL_CONFIGURATION_MONO,
                    AudioFormat.ENCODING_PCM_16BIT, rBufferSize);

        }catch (Exception e) {
            String msg = "ERROR init: "+e.getStackTrace();
            VoiceHcentActivity.this.toastMsg(msg);
        }
    }

    /**
     * 开始录音
     */
    public void startRecord(){
        stopSpeech = false;
        vspeech = new VoiceSpeech();
        vspeech.start();
    }

    /**
     * 结束录音
     */
    public void stopRecord() {
        stopSpeech = true;
    }

    /**
     * 开始播放录音
     */
    public void startPlay(){

        //设置播放器音量
        player.setStereoVolume(0.7f, 0.7f);

        player.play();
    }

    /**
     * 结束播放录音
     */
    public void stopPlay(){
        player.stop();
    }

    public void test(){

        startSpeech.setOnTouchListener(new View.OnTouchListener() {

            public boolean onTouch(View arg0, MotionEvent arg1) {

                switch (arg1.getAction()) {

                    case MotionEvent.ACTION_DOWN: //开始说话
                        startPlay();
                        startRecord();

                        toastMsg("starting record!");
                        break;

                    case MotionEvent.ACTION_UP: //停止说话
                        Log.i("hcent", "111");
                        stopPlay();
                        Log.i("hcent", "222");
                        stopRecord();
                        toastMsg("stoped record!");
                        break;

                    default:
                        break;
                }

                return false;
            }
        });

    }

    public class VoiceSpeech extends Thread{

        @Override
        public void run() {
            super.run();
            try {
                byte[] tempBuffer, readBuffer = new byte[rBufferSize];
                int bufResult = 0;
                recorder.startRecording();
                while(!stopSpeech){
                    bufResult = recorder.read(readBuffer, 0, rBufferSize);
                    if(bufResult>0 && bufResult%2==0){
                        tempBuffer = new byte[bufResult];
                        System.arraycopy(readBuffer, 0, tempBuffer, 0, rBufferSize);
                        player.write(tempBuffer, 0, tempBuffer.length);
                    }
                    Log.d("hcent", "get read:"+bufResult+"___"+readBuffer.length);
                }
                recorder.stop();
                Looper.prepare();
                VoiceHcentActivity.this.toastMsg("AudioSpeech have ended!");
                Looper.loop(); 
            } catch (Exception e) {
                String msg = "ERROR AudioRecord: "+e.getStackTrace();
                Looper.prepare();
                VoiceHcentActivity.this.toastMsg(msg);
                Looper.loop();
            }     
        }
    }
    @Override
    protected void onDestroy(){
        player.release();
        recorder.release();
        super.onDestroy();
        Process.killProcess(Process.myPid());
    }
    public void toastMsg(String msg){
        Toast.makeText(this, msg, Toast.LENGTH_SHORT).show();
        Log.e("hcent", msg);
    } 
}