我试图获得表达为分贝的声级压力,但总是得到0。(TextView的输出是-Infinity,因为log(0)=-Infinity。)
但是仍然得到-无穷大的结果。
public class SLP extends Activity{
TextView sound;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.sound_activity);
MediaRecorder recorder = new MediaRecorder();
recorder.setAudioSource(MediaRecorder.AudioSource.MIC);
recorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
recorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
Timer timer = new Timer();
timer.scheduleAtFixedRate(new RecorderTask(recorder), 0, 500);
}
private class RecorderTask extends TimerTask {
TextView sound = (TextView) findViewById(R.id.decibel);
private MediaRecorder recorder;
public RecorderTask(MediaRecorder recorder) {
this.recorder = recorder;
}
public void run() {
runOnUiThread(new Runnable() {
@Override
public void run() {
int amplitude = recorder.getMaxAmplitude();
double amplitudeDb = 20 * Math.log10((double)Math.abs(amplitude) / 32768);
sound.setText("" + amplitudeDb);
}
});
}
}
Manifest.xml
中的权限:
<uses-permission android:name="android.permission.RECORD_AUDIO" />
请问您需要帮助吗?
更新
我也尝试了以下方法:
MediaRecorder recorder = new MediaRecorder();
recorder.setAudioSource(MediaRecorder.AudioSource.MIC);
recorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
recorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
recorder.setOutputFile("/dev/null");
try {
recorder.prepare();
} catch (IOException e) {
e.printStackTrace();
}
recorder.start();
Timer timer = new Timer();
timer.scheduleAtFixedRate(new RecorderTask(recorder), 0, 500);
recorder.reset();
}
private class RecorderTask extends TimerTask {
TextView risultato = (TextView) findViewById(R.id.decibel);
private MediaRecorder recorder;
public RecorderTask(MediaRecorder recorder) {
this.recorder = recorder;
}
public double getAmplitude() {
if (recorder != null)
return (recorder.getMaxAmplitude());
else
return 0;
}
public void run() {
runOnUiThread(new Runnable() {
@Override
public void run() {
int amplitude = recorder.getMaxAmplitude();
double amplitudeDb = 20 * Math.log10(getAmplitude() / 32768);
//double db = 20 * Math.log(recorder.getMaxAmplitude() / 2700.0);
risultato.setText("" + amplitudeDb);
}
});
}
}
但是仍然得到-无穷大的结果。