Android: Streaming audio over TCP Sockets

Question

For my app, I need to record audio from MIC on an Android phone, and send it over TCP to the other android phone, where it needs to be played.

I am using AudioReco

Answer 1

The problem is lying here:

  bufferRead = recordInstance.read(tempBuffer, 0, bufferSize);
  dataOutputStreamInstance.write(tempBuffer);

You read bufferRead worth of bytes but you attempt to write whole buffer to the output stream.

To improve the recording process, you may consider following points:

1. Enable NoiseSuppressor (since API 16)
2. Enable AcousticEchoCanceler (since API 16)
3. Increase initial buffersize and should read a chunk of bytes smaller than initial buffersize for smoother audiostream
4. Switch to UDP. Streaming is UDP job.

Here is my setup for my previous android app:

// Calculate minimum buffer size
int minBufferSize = AudioRecord.getMinBufferSize(44100, AudioFormat.CHANNEL_IN_MONO,
                                                 AudioFormat.ENCODING_PCM_16BIT);
// Initialize AudioRecord for getting audio from device
AudioRecord recorder = new AudioRecord(MediaRecorder.AudioSource.MIC, 44100,
                                            AudioFormat.CHANNEL_IN_MONO,
                                            AudioFormat.ENCODING_PCM_16BIT, minBufferSize * 4);

if (API > API 16) {
    if (NoiseSuppressor.isAvailable()) {
        NoiseSuppressor.create(recorder.getAudioSessionId()).setEnabled(true);
    }
    if (AcousticEchoCanceler.isAvailable()) {
        AcousticEchoCanceler.create(recorder.getAudioSessionId()).setEnabled(true);
    }
}

....

byte[] tempBuffer = new byte[minBufferSize];
while (/*isRecording*/) {
      bufferRead = recordInstance.read(tempBuffer, 0, minBufferSize);
      dataOutputStreamInstance.write(tempBuffer, 0, bufferRead);
}