Android: Streaming audio over TCP Sockets

Chaitanya picture Chaitanya · May 1, 2010 · Viewed 17.5k times · Source

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 AudioRecord and AudioTrack class. This works great with a file - write audio to the file using DataOutputStream, and read from it using DataInputStream.

However, if I obtain the same stream from a socket instead of a File, and try writing to it, I get an exception.

I am at a loss to understand what could possibly be going wrong. Any help would be greatly appreciated.

EDIT: The problem is same even if I try with larger buffer sizes (65535 bytes, 160000 bytes).

This is the code:

Recorder:

int bufferSize = AudioRecord.getMinBufferSize(11025, , AudioFormat.CHANNEL_CONFIGURATION_MONO, AudioFormat.ENCODING_PCM_16BIT); 

AudioRecord recordInstance = new AudioRecord(MediaRecorder.AudioSource.MIC, 11025, AudioFormat.CHANNEL_CONFIGURATION_MONO, AudioFormat.ENCODING_PCM_16BIT, bufferSize);

byte[] tempBuffer = new byte[bufferSize];

recordInstance.startRecording();

while (/*isRecording*/) {
      bufferRead = recordInstance.read(tempBuffer, 0, bufferSize);
      dataOutputStreamInstance.write(tempBuffer);
}

The DataOutputStream above is obtained as:

BufferedOutputStream buff = new BufferedOutputStream(out1); //out1 is the socket's outputStream
DataOutputStream dataOutputStreamInstance = new DataOutputStream (buff);

Could you please have a look, and let me know what is it that I could be doing wrong here?

Thanks,

Answer

Chaitanya picture Chaitanya · May 2, 2010

I got this working, with some help, and only partially.

I started off with the code at http://emeadev.blogspot.com/2009/09/raw-audio-manipulation-in-android.html, changed File's streams to Socket's streams, and changed the isAvailable() to if(inputStream.read(byteArray) != -1).

Live streaming of audio over TCP is happening now.

However,

All I hear at the other end is noise, and I am now hunting for correct set of parameters for AudioRecorder and AudioTrack - the frequency, channel config and encoding, audio source etc.

If you have any idea about this, please let me know.

Thanks,

EDIT: It was a stupid error on my part. In addition to all I have said above, use inputStream on player side and outputStream on recorder side, and byte arrays instead of shorts and it will work. :)