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. /*from  w ww. j a v a  2 s  .  co m*/
 *   
 *   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.decode.pcm;

import java.io.DataInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;

import bg.cytec.android.fskmodem.FSKConfig;
import bg.cytec.android.fskmodem.FSKDecoder;
import bg.cytec.android.fskmodem.FSKDecoder.FSKDecoderCallback;
import android.support.v7.app.ActionBarActivity;
import android.widget.TextView;
import android.os.Bundle;

public class MainActivity extends ActionBarActivity {

  protected FSKConfig mConfig;
  protected FSKDecoder mDecoder;
  
  protected Runnable mPCMFeeder = new Runnable() {
    
    @Override
    public void run() {
      try {
        //open input stream to the signed 16bit raw PCM file
        InputStream input = getResources().getAssets().open("pcm_signed_16bit.raw");
        DataInputStream data = new DataInputStream(input);

        //the decoder has 1 second buffer (equals to sample rate), 
        //so we have to fragment the entire file, 
        //to prevent buffer overflow or rejection
        short[] buffer = new short[1024];
        int pointer = 0;
            
        //feed signal little by little... another way to do that is to 
        //check the returning value of appendSignal(), it returns the 
        //remaining space in the decoder signal buffer
        while (data.available() > 0) {
          //since this time we process 16bit data, 
          //we have to convert it to shorts first
          ByteBuffer bytes = ByteBuffer.allocate(2);
          bytes.order(ByteOrder.LITTLE_ENDIAN);
          
          bytes.put((byte) data.read());
          bytes.put((byte) data.read());
          bytes.rewind();
          
          buffer[pointer] = bytes.getShort();
          pointer++;
          
          if (pointer == 1024 || data.available() == 0) {
            mDecoder.appendSignal(buffer);
            
            Thread.sleep(100); //give the decoder time to consume
            
            buffer = new short[1024];
            pointer = 0;
          }
        }
        
        data.close();
        
      } catch (IOException e) {
        e.printStackTrace();
      } catch (InterruptedException e) {
        e.printStackTrace();
      }
    }
  };

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    
    /// INIT FSK CONFIG
    
    try {
      mConfig = new FSKConfig(FSKConfig.SAMPLE_RATE_29400, FSKConfig.PCM_16BIT, 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);
          }
        });
      }
    });
    
    ///
    
    new Thread(mPCMFeeder).start();
  }
  
  @Override
  protected void onDestroy() {
    
    mDecoder.stop();
    
    super.onDestroy();
  }

}

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