Sound Level

To know the level of noise one calculates the Root-Mean-Square (RMS) of a sample of audio data.

This code is for 16 bit audio.

private static int calculateRMSLevel(byte[] audioData) {

  long lSum = 0;
  for (int i = 0; i < audioData.length; i += 2) {
    int val = (short) (((audioData[i + 1] & 0xff) << 8) | (audioData[i] & 0xff));
    lSum += val;
  }

  double dAvg = lSum / audioData.length;

  double sumMeanSquare = 0d;
  for (int i = 0; i < audioData.length; i += 2) {
    int val = (short) (((audioData[i + 1] & 0xff) << 8) | (audioData[i] & 0xff));
    sumMeanSquare += Math.pow(val - dAvg, 2d);
  }

  double averageMeanSquare = sumMeanSquare / audioData.length / 2;
  return (int) (Math.pow(averageMeanSquare, 0.5d) + 0.5);

}