我对 Android 很陌生,我已经搜索了很长一段时间了。我想构建一个类似于分贝计的应用程序。它实时显示声音级别。如果房间里噪音很大,就会有一些指示,如果房间很安静,就会有一些指示!
我根本不知道如何做到这一点。谁能解释一下麦克风声级应用的基础知识是什么?如果可能的话,也许提供一些代码?
Thanks!
您可以使用MediaRecorder.getMaxAmplitude()
.
if (ActivityCompat.checkSelfPermission(this, Manifest.permission.RECORD_AUDIO) != PackageManager.PERMISSION_GRANTED) {
ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.RECORD_AUDIO},
RECORD_AUDIO);
}
-
使用 MediaRecorder 获取噪音级别,
mRecorder = new MediaRecorder();
mRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
mRecorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
mRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
mRecorder.setOutputFile("/dev/null");
try {
mRecorder.prepare();
} catch (IllegalStateException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
mRecorder.start();
-
启动媒体记录器,
private Runnable mSleepTask = new Runnable() {
public void run() {
//Log.i("Noise", "runnable mSleepTask");
mSensor.start();
if (!mWakeLock.isHeld()) {
mWakeLock.acquire();
}
//Noise monitoring start
// Runnable(mPollTask) will execute after POLL_INTERVAL
mHandler.postDelayed(mPollTask, POLL_INTERVAL);
}
};
-
创建可运行线程来经常检查噪音水平,
private Runnable mPollTask = new Runnable() {
public void run() {
double amp = mSensor.getAmplitude();
//Log.i("Noise", "runnable mPollTask");
// Runnable(mPollTask) will again execute after POLL_INTERVAL
mHandler.postDelayed(mPollTask, POLL_INTERVAL);
}
};
使用以下公式将振幅转换为分贝,
return 20 * Math.log10(mRecorder.getMaxAmplitude() / 2700.0);
-
监控声音并发出较大噪音警报。
// Create runnable thread to Monitor Voice
private Runnable mPollTask = new Runnable() {
public void run() {
double amp = mSensor.getAmplitude();
//Log.i("Noise", "runnable mPollTask");
updateDisplay("Monitoring Voice...", amp);
if ((amp > mThreshold)) {
callForHelp(amp);
//Log.i("Noise", "==== onCreate ===");
}
// Runnable(mPollTask) will again execute after POLL_INTERVAL
mHandler.postDelayed(mPollTask, POLL_INTERVAL);
}
};
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