apps/CtsVerifier/src/com/android/cts/verifier/audio/AudioRecordHelper.java

package com.android.cts.verifier.audio;

import android.media.AudioFormat;
import android.media.AudioManager;
import android.media.AudioRecord;
import android.media.AudioTrack;
import android.media.MediaRecorder;
import android.util.Log;

import java.io.ByteArrayOutputStream;
import java.io.IOException;

/**
 * A wrapper on AudioRecord class.
 */
public class AudioRecordHelper {

  private static final int[] SOURCE = {
      MediaRecorder.AudioSource.MIC, MediaRecorder.AudioSource.VOICE_RECOGNITION};
  private static final int[] SAMPLE_RATES_HZ = {
    AudioTrack.getNativeOutputSampleRate(AudioManager.STREAM_MUSIC), 48000, 44100};

  private static final int CHANNEL = AudioFormat.CHANNEL_CONFIGURATION_MONO;
  private static final int ENCODING = AudioFormat.ENCODING_PCM_16BIT;
  private static final String TAG = "AudioRecordHelper";
  private static AudioRecordHelper instance;
  private final int bufferSize;
  private final int sampleRate;
  private final int source;
  private ByteArrayOutputStream os;
  private AudioRecord audioRecord;
  private volatile boolean isRecording = false;

  private AudioRecordHelper() {
    int tmpBufferSize = 0;
    int tmpSampleRate = 0;
    int tmpSource = 0;
    initialization:
    for (int source : SOURCE) {
      for (int rate : SAMPLE_RATES_HZ) {
        tmpBufferSize = AudioRecord.getMinBufferSize(rate, CHANNEL, ENCODING);
        AudioRecord testAudioRecord = new AudioRecord(source, rate, CHANNEL, ENCODING,
            tmpBufferSize);
        if (testAudioRecord.getState() == AudioRecord.STATE_INITIALIZED) {
          testAudioRecord.release();
          tmpSampleRate = rate;
          tmpSource = source;
          break initialization;
        }
      }
    }
    if (tmpBufferSize == 0 || tmpSampleRate == 0) {
      Log.e(TAG, "Failed to initialize");
    }
    bufferSize = tmpBufferSize;
    sampleRate = tmpSampleRate;
    source = tmpSource;
    Log.d(TAG, "Sample rate = " + sampleRate + "Hz, Source = "
        + source + " (VOICE_RECOGNITION = 6 , MIC = 1)");
  }

  public static AudioRecordHelper getInstance() {
    if (instance == null) {
      instance = new AudioRecordHelper();
    }
    return instance;
  }

  /**
   * Start recording.
   */
  public void start() {
    if (!isRecording) {
      isRecording = true;
      os = new ByteArrayOutputStream();
      audioRecord = new AudioRecord(source, sampleRate, CHANNEL, ENCODING, bufferSize);
      audioRecord.startRecording();
      startPullingData();
    }
  }

  /**
   * Stop recording
   */
  public void stop() {
    if (isRecording) {
      isRecording = false;
      audioRecord.stop();
      audioRecord.release();
      audioRecord = null;
      try {
        os.close();
      } catch (IOException e) {
        e.printStackTrace();
      }
    }
  }

  private void startPullingData() {
    new Thread() {
      @Override
      public void run(){
        byte data[] = new byte[bufferSize];
        while (isRecording) {
          int read = audioRecord.read(data, 0, bufferSize);
          if (read > 0) {
            os.write(data, 0, read);
          }
          if (read < 0) {
            break;
          }
        }
      }
    }.start();
  }

  /**
   * Returns the sample rate for this recorder.
   */
  public int getSampleRate() {
    return sampleRate;
  }

  /**
   * Returns the audio source currently being used.
   */
  public int getAudioSource() {
    return source;
  }

  /**
   * Returns true if recorder is recording; False if not.
   */
  public boolean isRecording() {
    return isRecording;
  }

  /**
   * Returns the raw data.
   */
  public byte[] getByte() {
    return os.toByteArray();
  }
}