Android Open Source - android-fskmodem Main Activity

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License

The source code is released under:

GNU General Public License

Java Source Code

/**    
 *   This file is part of the FSKModem java/android library for 
 *   processing FSK audio signals. //  w ww  . j a  va2s. c  om
 *   
 *   The FSKModem library is developed by Ivan Ganev, CEO at
 *   Cytec BG Ltd.
 *
 *   Copyright (C) 2014  Cytec BG Ltd. office@cytec.bg
 *
 *   This program is free software: you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation, either version 3 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

package bg.cytec.android.fskmodem.examples.encode.live8bit;

import java.io.IOException;
import java.nio.ByteBuffer;

import bg.cytec.android.fskmodem.FSKConfig;
import bg.cytec.android.fskmodem.FSKDecoder;
import bg.cytec.android.fskmodem.FSKDecoder.FSKDecoderCallback;
import bg.cytec.android.fskmodem.FSKEncoder;
import bg.cytec.android.fskmodem.FSKEncoder.FSKEncoderCallback;
import android.support.v7.app.ActionBarActivity;
import android.widget.TextView;
import android.media.AudioFormat;
import android.media.AudioManager;
import android.media.AudioTrack;
import android.os.Bundle;

public class MainActivity extends ActionBarActivity {

  public static final String ENCODER_DATA = "Hello World! This text has been encoded realtime and then fed to audio playback stream and the FSK decoder that actually displays it.";
  
  protected FSKConfig mConfig;
  protected FSKEncoder mEncoder;
  protected FSKDecoder mDecoder;
  
  protected AudioTrack mAudioTrack;
  
  protected Runnable mDataFeeder = new Runnable() {
    
    @Override
    public void run() {
      byte[] data = ENCODER_DATA.getBytes();
      
      if (data.length > FSKConfig.ENCODER_DATA_BUFFER_SIZE) {
        //chunk data
        
        byte[] buffer = new byte[FSKConfig.ENCODER_DATA_BUFFER_SIZE];
        
        ByteBuffer dataFeed = ByteBuffer.wrap(data);
        
        while (dataFeed.remaining() > 0) {
          
          if (dataFeed.remaining() < buffer.length) {
            buffer = new byte[dataFeed.remaining()];
          }
          
          dataFeed.get(buffer);
          
          mEncoder.appendData(buffer);
          
          try {
            Thread.sleep(100); //wait for encoder to do its job, to avoid buffer overflow and data rejection
          } catch (InterruptedException e) {
            e.printStackTrace();
          }
        }
      }
      else {
        mEncoder.appendData(data);
      }
    }
  };

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    
    /// INIT FSK CONFIG
    
    try {
      mConfig = new FSKConfig(FSKConfig.SAMPLE_RATE_44100, FSKConfig.PCM_8BIT, FSKConfig.CHANNELS_MONO, FSKConfig.SOFT_MODEM_MODE_4, FSKConfig.THRESHOLD_20P);
    } catch (IOException e1) {
      e1.printStackTrace();
    }

    /// INIT FSK DECODER
    
    mDecoder = new FSKDecoder(mConfig, new FSKDecoderCallback() {
      
      @Override
      public void decoded(byte[] newData) {
        
        final String text = new String(newData);
        
        runOnUiThread(new Runnable() {
          public void run() {
            
            TextView view = ((TextView) findViewById(R.id.result));
            
            view.setText(view.getText()+text);
          }
        });
      }
    });
    
    /// INIT FSK ENCODER
    
    mEncoder = new FSKEncoder(mConfig, new FSKEncoderCallback() {
      
      @Override
      public void encoded(byte[] pcm8, short[] pcm16) {
        if (mConfig.pcmFormat == FSKConfig.PCM_8BIT) {
          //8bit buffer is populated, 16bit buffer is null
          
          mAudioTrack.write(pcm8, 0, pcm8.length);
          
          mDecoder.appendSignal(pcm8);
        }
        else if (mConfig.pcmFormat == FSKConfig.PCM_16BIT) {
          //16bit buffer is populated, 8bit buffer is null
          
          mAudioTrack.write(pcm16, 0, pcm16.length);
          
          mDecoder.appendSignal(pcm16);
        }
      }
    });
    
    ///
    
    mAudioTrack = new AudioTrack(AudioManager.STREAM_MUSIC,
        mConfig.sampleRate, AudioFormat.CHANNEL_OUT_MONO,
        AudioFormat.ENCODING_PCM_8BIT, 1024,
        AudioTrack.MODE_STREAM);
    
    mAudioTrack.play();
    
    ///
    
    new Thread(mDataFeeder).start();
  }
  
  @Override
  protected void onDestroy() {
    mDecoder.stop();
    
    mEncoder.stop();
    
    mAudioTrack.stop();
    mAudioTrack.release();
    
    super.onDestroy();
  }

}

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