Is there a significant delay in initializing AudioTrack?

Is there a significant delay in initializing AudioTrack?

I am trying to pass through the audio samples obtained at the MIC to the
speaker using AudioRecord and AudioTrack. Here is the code:
public class MainActivity extends Activity {
AudioManager am = null;
AudioRecord record =null;
AudioTrack track =null;
final int SAMPLE_FREQUENCY = 44100;
final int SIZE_OF_RECORD_ARRAY = 1024; // 1024 ORIGINAL
final int WAV_SAMPLE_MULTIPLICATION_FACTOR = 1;
int i= 0;
boolean isPlaying = true;
class MyThread extends Thread{
private volatile boolean passThroughMode = true;
// /*
MyThread(){
super();
}
MyThread(boolean newPTV){
this.passThroughMode = newPTV;
}
// */
// /*
@Override
public void run(){
short[] lin = new short[SIZE_OF_RECORD_ARRAY];
int num = 0;
// am = (AudioManager)
this.getSystemService(Context.AUDIO_SERVICE); // -> MOVED
THESE TO init()
// am.setMode(AudioManager.MODE_IN_COMMUNICATION);
record.startRecording();
track.play();
while (passThroughMode) {
// while (!isInterrupted()) {
num = record.read(lin, 0, SIZE_OF_RECORD_ARRAY);
for(i=0;i<lin.length;i++)
lin[i] *= WAV_SAMPLE_MULTIPLICATION_FACTOR;
track.write(lin, 0, num);
}
// /*
record.stop();
track.stop();
record.release();
track.release();
// */
}
// */
// /*
public void stopThread(){
passThroughMode = false;
}
// */
}
MyThread newThread;
private void init() {
int min = AudioRecord.getMinBufferSize(SAMPLE_FREQUENCY,
AudioFormat.CHANNEL_IN_MONO, AudioFormat.ENCODING_PCM_16BIT);
record = new
AudioRecord(MediaRecorder.AudioSource.VOICE_COMMUNICATION,
SAMPLE_FREQUENCY, AudioFormat.CHANNEL_IN_MONO,
AudioFormat.ENCODING_PCM_16BIT, min);
int maxJitter = AudioTrack.getMinBufferSize(SAMPLE_FREQUENCY,
AudioFormat.CHANNEL_OUT_MONO, AudioFormat.ENCODING_PCM_16BIT);
track = new AudioTrack(AudioManager.MODE_IN_COMMUNICATION,
SAMPLE_FREQUENCY, AudioFormat.CHANNEL_OUT_MONO,
AudioFormat.ENCODING_PCM_16BIT, maxJitter,
AudioTrack.MODE_STREAM);
am = (AudioManager) this.getSystemService(Context.AUDIO_SERVICE);
am.setMode(AudioManager.MODE_IN_COMMUNICATION);
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
setVolumeControlStream(AudioManager.MODE_IN_COMMUNICATION);
// init(); // -> Moved this to onResume();
Log.d("MYLOG", "onCreate() called");
}
@Override
protected void onResume(){
super.onResume();
// newThread.stopThread();
Log.d("MYLOG", "onResume() called");
init();
newThread = new MyThread(true);
newThread.start();
}
@Override
protected void onPause(){
super.onPause();
Log.d("MYLOG", "onPause() called");
newThread.stopThread();
// android.os.Process.killProcess(android.os.Process.myPid());
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is
present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
public void passStop(View view){
Button playBtn = (Button) findViewById(R.id.playBtn);
// /*
if(!isPlaying){
record.startRecording();
track.play();
isPlaying = true;
playBtn.setText("Pause");
}
else{
record.stop();
track.pause();
isPlaying=false;
playBtn.setText("Pass through");
}
// */
}
// /*
@Override
protected void onDestroy() {
super.onDestroy();
newThread.stopThread();
// android.os.Process.killProcess(android.os.Process.myPid());
// killProcess(android.os.Process.myPid());
// newThread.interrupt();
Log.d("MYLOG", "onDestroy() called");
}
// */
}
The program is supposed to start a Thread that performs a pass through.
The Thread starts at the app's onResume() so should start immediately. But
there is always a 1.5~2 sec delay at the beginning. I assumed that it
might be because of onCreate() and other initialization happening before
the Thread starts in onResume(), but if I print out the contents of the
lin array to file, it always writes a long line of 0's at the beginning
which indicates the delay is probably not due tot he time required for
initializing. So what is this delay seen here? Does track.play() need a
significant time to start playing?