audio - android: Detect sound level

Question

Using MediaRecorder I capture sound from device's microphone. From the sound I get I need only to analyze the sound volume (sound loudness), without saving the sound to a file.

Two questions:

1. How do I get the loudness for the sound at a given moment in time?
2. How do I do the analyze without saving the sound to a file?

Thank you.

Answer 1

1. Use mRecorder.getMaxAmplitude();

2. For the analysis of sound without saving all you need is use mRecorder.setOutputFile("/dev/null");

Here′s an example, I hope this helps

public class SoundMeter {

    private MediaRecorder mRecorder = null;

    public void start() {
            if (mRecorder == null) {
                    mRecorder = new MediaRecorder();
                    mRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
                    mRecorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
                    mRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
                    mRecorder.setOutputFile("/dev/null"); 
                    mRecorder.prepare();
                    mRecorder.start();
            }
    }

    public void stop() {
            if (mRecorder != null) {
                    mRecorder.stop();       
                    mRecorder.release();
                    mRecorder = null;
            }
    }

    public double getAmplitude() {
            if (mRecorder != null)
                    return  mRecorder.getMaxAmplitude();
            else
                    return 0;

    }
}