주파수 출력 예제인데요..

Question

주파수 출력 예제를 그대로 적어봤는데요

package org.techtown.audioprocessing;

import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.media.AudioFormat;
import android.media.AudioRecord;
import android.media.MediaRecorder;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ImageView;


public class MainActivity extends Activity implements OnClickListener {
    int frequency = 8000;
    int channelConfiguration = AudioFormat.CHANNEL_CONFIGURATION_MONO;
    int audioEncoding = AudioFormat.ENCODING_PCM_16BIT;

    private RealDoubleFFT transformer;
    int blockSize = 256;

    Button startStopButton;
    boolean started = false;

    RecordAudio recordTask;

    ImageView imageView;
    Bitmap bitmap;
    Canvas canvas;
    Paint paint;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        startStopButton = (Button) this.findViewById(R.id.StartStopButton);
        startStopButton.setOnClickListener(this);

        transformer = new RealDoubleFFT(blockSize);

        imageView = (ImageView) this.findViewById(R.id.ImageView01);
        bitmap = Bitmap.createBitmap( 256,  100, Bitmap.Config.ARGB_8888);
        canvas = new Canvas(bitmap);
        paint = new Paint();
        paint.setColor(Color.GREEN);
        imageView.setImageBitmap(bitmap);
    }



    private class RecordAudio extends AsyncTask<Void, double[], Void> {
        @Override
        protected Void doInBackground(Void... params) {
            try {
                int bufferSize = AudioRecord.getMinBufferSize(frequency, channelConfiguration, audioEncoding);

                AudioRecord audioRecord = new AudioRecord(MediaRecorder.AudioSource.MIC, frequency, channelConfiguration, audioEncoding, bufferSize);

                short[] buffer = new short[blockSize];
                double[] toTransform = new double[blockSize];

                audioRecord.startRecording();

                while (started) {
                    int bufferReadResult = audioRecord.read(buffer, 0, blockSize);

                    for (int i = 0; i < blockSize && i < bufferReadResult; i++) {
                        toTransform[i] = (double) buffer[i];
                    }

                    transformer.ft(toTransform);

                    publishProgress(toTransform);
                }

                audioRecord.stop();
            } catch (Throwable t) {
                Log.e("AudioRecord", "Recording Failed");
            }

            return null;
        }

        protected void onProgressUpdate(double[]... toTransform) {
            canvas.drawColor(Color.BLACK);

            for (int i = 0; i < toTransform[0].length; i++) {

                int downy = (int) (100 - (toTransform[0][i] * 10));
                int upy = 100;

                canvas.drawLine(i, downy, i, upy, paint);
            }
            imageView.invalidate();
        }
    }

    public void onClick(View v) {
        if(started) {
            started = false;
            startStopButton.setText("Start");
            recordTask.cancel(true);
        } else {
            started = true;
            startStopButton.setText("Stop");
            recordTask = new RecordAudio();
            recordTask.execute();
        }
    }
}

 

코드 상 오류는 없는데 에뮬레이터 실행하여 녹음시작 버튼을 누르게 되면 아래와 같은

logcat 오류가 나옵니다. 해결할 방법 좀 설명해주세요..ㅠ

10-16 14:45:23.049 15238-15480/org.techtown.audioprocessing E/AudioRecord: AudioFlinger could not create record track, status: -1
10-16 14:45:23.053 15238-15480/org.techtown.audioprocessing E/AudioRecord-JNI: Error creating AudioRecord instance: initialization check failed with status -1.
10-16 14:45:23.053 15238-15480/org.techtown.audioprocessing E/android.media.AudioRecord: Error code -20 when initializing native AudioRecord object.
10-16 14:45:23.053 15238-15480/org.techtown.audioprocessing E/AudioRecord: Recording Failed