How to decrease the latency of the RTP streaming with ffmpeg in Android?

I'm creating a App that do a RTP streaming. It uses a ParcelFileDescriptor pipe pair, where a MediaRecorder writes in the pipe while the ffmpeg receives the audio from the pipe and sends by RTP.

In my desktop, using the same wifi router, I receive the RTP stream using ffplay, and it has a delay between 5s ~ 10s.

I tried capture audio using ffmpeg in Android, but itsn't possible. I tried to use ffplay -fflags nobuffer, use MIC as source, change the encoder, etc.

I need the lowest delay possible. How can I do it?

The code:

public class MainActivity extends AppCompatActivity implements View.OnClickListener
MediaRecorder mediaRecorder;
AudioRecord record;
MediaPlayer mediaPlayer;
ParcelFileDescriptor pipePair;
ParcelFileDescriptor pipeRead;
ParcelFileDescriptor pipeWrite;
Process ffmpegProc;
// Requesting permission to RECORD_AUDIO
private boolean permissionsAccepted = false;
private String permissions =
Manifest.permission.RECORD_AUDIO,
Manifest.permission.INTERNET,
Manifest.permission.ACCESS_NETWORK_STATE
;
private static final int REQUEST_PERMISSIONS = 200;

@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String permissions, @NonNull int grantResults)
super.onRequestPermissionsResult(requestCode, permissions, grantResults);
switch (requestCode)
case REQUEST_PERMISSIONS:
permissionsAccepted = grantResults[0] == PackageManager.PERMISSION_GRANTED;
break;

if (!permissionsAccepted ) finish();



@Override
protected void onCreate(Bundle savedInstanceState)
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ActivityCompat.requestPermissions(this, permissions, REQUEST_PERMISSIONS);

TextView hello = (TextView) findViewById(R.id.hello);
hello.setOnClickListener(new View.OnClickListener()
@Override
public void onClick(View view)
Toast.makeText(MainActivity.this, "Clicado",Toast.LENGTH_SHORT)
.show();
copiarFFMpeg();


);



private void executarFFMpeg(final String cmd, ParcelFileDescriptor read)

try
ffmpegProc = Runtime.getRuntime().exec(cmd);
catch (IOException e)
e.printStackTrace();


(new Thread(new Runnable()
@Override
public void run()
try
InputStream inStream = ffmpegProc.getInputStream();
InputStreamReader sReader = new InputStreamReader(inStream);
BufferedReader bufferedReader = new BufferedReader(sReader);
String line;
while ((line = bufferedReader.readLine()) != null)
Log.d("FFMPEG",line);

catch (IOException e)
e.printStackTrace();


)).start();

(new Thread(new Runnable()
@Override
public void run()
byte buffer = new byte[8192];
int read = 0;

OutputStream ffmpegInput = ffmpegProc.getOutputStream();
FileInputStream reader = new FileInputStream(pipeRead.getFileDescriptor());

try

while (true)

if (reader.available()>0)
read = reader.read(buffer);
ffmpegInput.write(buffer, 0, read);
ffmpegInput.flush();
else
Thread.sleep(10);




catch (InterruptedException e)
e.printStackTrace();

catch (IOException e)
e.printStackTrace();

onDestroy();


)).start();

Log.d("FFMPEG","Executado");


private boolean estaExecutando(Process ffmpegProc)
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O)
return ffmpegProc.isAlive();
else
try
ffmpegProc.exitValue();
return false;
catch (Exception e)
return true;




private void criarMediaRecorder()
if (pipeWrite != null)
try
//ffplay.exe -protocol_whitelist rtp,file,udp ..file.sdp
mediaRecorder = new MediaRecorder();
mediaRecorder.setAudioSource(MediaRecorder.AudioSource.VOICE_COMMUNICATION);
mediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.AAC_ADTS);
mediaRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AAC);
//mediaRecorder.setAudioChannels(2);
mediaRecorder.setOutputFile(pipeWrite.getFileDescriptor());
mediaRecorder.prepare();
mediaRecorder.start();
Log.d("MREC","MediaRecorder criado");
catch (Exception e)
e.printStackTrace();




private void criarPipe()
try
pipePair =ParcelFileDescriptor.createPipe();
catch (IOException e)
Log.e("PIPE","Deu zica na criação do pipe");
e.printStackTrace();
finish();

pipeRead = new ParcelFileDescriptor(pipePair[0]);
pipeWrite = new ParcelFileDescriptor(pipePair[1]);


private void copiarFFMpeg()
FFmpeg ffmpeg = FFmpeg.getInstance(this);
try
ffmpeg.loadBinary(new LoadBinaryResponseHandler()

@Override
public void onStart()
Log.d("FFMPEG","Iniciar cópia");


@Override
public void onFailure()
Log.e("FFMPEG","Cópia falhou");


@Override
public void onSuccess()
Log.d("FFMPEG","Cópiado com sucesso");

criarPipe();
//mediaRecorder.start();
File ffmpegBin = new File(getFilesDir().getAbsolutePath()+"/ffmpeg");
String cmd = new String
ffmpegBin.getAbsolutePath(),
"-re",
"-thread_queue_size","4",
"-i","pipe:",
//"-c:a","libx264",
//"-preset","veryfast",
//"-tune","zerolatency",
"-f",
"rtp",
"rtp://192.168.0.33:1234"
;

executarFFMpeg(cmd, pipeRead);

criarMediaRecorder();


@Override
public void onFinish()

);
catch (FFmpegNotSupportedException e)
// Handle if FFmpeg is not supported by device
Log.e("FFMPEG", "Não sou suportado :/");



@Override
protected void onDestroy()
super.onDestroy();


@Override
public void onClick(View view)





The command:

ffplay rtp://192.168.0.33:1234

ffplay -fflags nobuffer rtp://192.168.0.33:1234


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