android 多媒体部分学习笔记九----数字音频合成

/**

* 数字音频合成

*

* @time 下午12:00:21

* @author retacn yue

* @Email zhenhuayue@sina.com

*/

public class Audio_synthesisActivity extends Activity implements OnClickListener {

private Button btn_start, btn_stop;

private boolean keepGoing = false;

private AudioSynthesisTask synthesisTask;

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

findView();

}

@Override

public void onClick(View v) {

if (v == btn_start) {// 开启音频合成任务,修改状态

keepGoing = true;

synthesisTask = new AudioSynthesisTask();

synthesisTask.execute();

btn_stop.setEnabled(true);

} else if (v == btn_stop) {// 停止合成任务，修改状态

keepGoing = false;

btn_stop.setEnabled(false);

btn_start.setEnabled(true);

}

}

/**

* 实例化控件

*/

private void findView() {

btn_start = (Button) this.findViewById(R.id.btn_start);

btn_start.setOnClickListener(this);

btn_stop = (Button) this.findViewById(R.id.btn_stop);

btn_stop.setOnClickListener(this);

btn_stop.setEnabled(false);

}

@Override

protected void onPause() {

super.onPause();

keepGoing = false;

btn_start.setEnabled(true);

btn_stop.setEnabled(false);

}

/**

* 音频合成任务

*/

private class AudioSynthesisTask extends AsyncTask<Void, Void, Void> {

@Override

protected Void doInBackground(Void... params) {

final int SAMPLE_RATE = 11025;

int minSize = AudioTrack.getMinBufferSize(SAMPLE_RATE, //

AudioFormat.CHANNEL_IN_MONO,// 常量： 16（0x00000010）

AudioFormat.ENCODING_PCM_16BIT);// PCM音频数据格式：16位，每样

AudioTrack audioTrack = new AudioTrack(AudioManager.STREAM_MUSIC,// 媒体音量

SAMPLE_RATE,//

AudioFormat.CHANNEL_IN_MONO,// 常量： 16（0x00000010）

AudioFormat.ENCODING_PCM_16BIT, // PCM音频数据格式：每个采样点16比特

minSize,//

// MODE_STATIC 音频数据放到一个固定的buffer, 然后一次写入

//MODE_STREAM 通过write方式把数据一次一次得写到audiotrack中

AudioTrack.MODE_STREAM//

);

audioTrack.play();

short[] buffer = { //

8130, 15752, 22389, 27625, 31134, 32695, 32210, 29711, 25354, 19410, 12253, //

4329, -3865, -11818, -19032, -25055, -29511, -32121, -32722, -31276, -27874, -22728, -16160, -8582, -466 //

};

while (keepGoing) {

audioTrack.write(buffer, 0, buffer.length);

}

return null;

}

}

}