Peer to Peer Audio Calling on Android : Voice breaks and lag(delay in receiving packets) increases
<p>I am trying to establish Peer to Peer audio calling on android. I used an android phone and a tablet for communication but after receiving around 40 packets the phone almost stops receiving the packets and then suddenly receives a few packets and plays them and so on but this waiting time increases. Similarly the tablet initially receives the packets and plays them but lag increases and also voice starts to break down after some time as if some packets are lost. Any idea whats causing this problem...</p>

<p>This is the code for app...i am just giving the sender's and receiver's ip address in RecordAudio class while running it on two devices.</p>

<pre><code>public class AudioRPActivity extends Activity implements OnClickListener {

    DatagramSocket socketS,socketR;
    DatagramPacket recvP,sendP;
    RecordAudio rt;
    PlayAudio pt;

    Button sr,stop,sp;
    TextView tv,tv1;
    File rf;

    boolean isRecording = false;
    boolean isPlaying = false;

    int frequency = 44100;
    int channelConfiguration = AudioFormat.CHANNEL_CONFIGURATION_MONO;
    int audioEncoding = AudioFormat.ENCODING_PCM_16BIT;

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

        tv = (TextView)findViewById(R.id.text1);
        tv1 = (TextView)findViewById(R.id.text2);

        sr = (Button)findViewById(R.id.sr);
        sp = (Button)findViewById(R.id.sp);
        stop = (Button)findViewById(R.id.stop);

        sr.setOnClickListener(this);
        sp.setOnClickListener(this);
        stop.setOnClickListener(this);

        stop.setEnabled(false);

        try
        {
        socketS=new DatagramSocket();
        socketR=new DatagramSocket(6000);
        }
        catch(SocketException se)
        {
            tv.setText(se.toString());
            finish();
        }
    }

    public void onClick(View v) {

        if(v == sr)
            record();
        else if(v == sp)
            play();
        else if(v == stop)
            stopPlaying();
    }

    public void play()
    {
        stop.setEnabled(true);
        sp.setEnabled(false);
        pt = new PlayAudio();
        pt.execute();
    }

    public void stopPlaying()
    {
        isRecording=false;
        isPlaying = false;
        stop.setEnabled(false);
    }

    public void record()
    {
        stop.setEnabled(true);
        sr.setEnabled(false);
        rt = new RecordAudio();
        rt.execute();
    }



    private class PlayAudio extends AsyncTask&lt;Void,String,Void&gt;
    {

        @Override
        protected Void doInBackground(Void... arg0)
        {
            isPlaying = true;
            int bufferSize = AudioTrack.getMinBufferSize(frequency, channelConfiguration, audioEncoding);

            byte[] audiodata = new byte[bufferSize];

            try
            {
                AudioTrack audioTrack = new AudioTrack(AudioManager.STREAM_MUSIC,frequency,channelConfiguration,
                                                        audioEncoding,4*bufferSize,AudioTrack.MODE_STREAM);
                audioTrack.setPlaybackRate(frequency);
                audioTrack.play();

                while(isPlaying)
                {
                    recvP=new DatagramPacket(audiodata,audiodata.length);
                    socketR.receive(recvP);
                    audioTrack.write(recvP.getData(), 0, recvP.getLength());
                }
                audioTrack.stop();
                audioTrack.release();
            }
            catch(Throwable t)
            {
                Log.e("Audio Track","Playback Failed");
            }
            return null;
        }
        protected void onProgressUpdate(String... progress)
        {
            tv1.setText(progress[0].toString());
        }

        protected void onPostExecute(Void result)
        {
            sr.setEnabled(true);
            sp.setEnabled(true);
        }

    }

    private class RecordAudio extends AsyncTask&lt;Void,String,Void&gt;
    {

        @Override
        protected Void doInBackground(Void... arg0)
        {
            isRecording = true;

            try
            {
                int bufferSize = AudioTrack.getMinBufferSize(frequency, channelConfiguration, audioEncoding);

                AudioRecord audioRecord = new AudioRecord(MediaRecorder.AudioSource.MIC,frequency,channelConfiguration
                                                            ,audioEncoding,4*bufferSize);   
                byte[] buffer = new byte[bufferSize];
                audioRecord.startRecording();
                int r=0;
                while(isRecording)
                {
                    int brr = audioRecord.read(buffer,0,bufferSize);

                    sendP=new DatagramPacket(buffer,brr,InetAddress.getByName("sender's/receiver's ip"),6000);
                    socketS.send(sendP);
                    publishProgress(String.valueOf(r));

                    r++;
                }

                audioRecord.stop();
                audioRecord.release();

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


            return null;
        }

        protected void onProgressUpdate(String... progress)
        {
            tv.setText(progress[0].toString());
        }

        protected void onPostExecute(Void result)
        {
            sr.setEnabled(true);
            sp.setEnabled(true);
        }
    }
}
</code></pre>
