Mixing two audio streams into a single audio stream in android?

Question

I am trying to mix two audio streams to get a single output stream is it possible in android? In my case, I have one input stream coming from Microphone, i.e, I am recording the users speech using AudioRecord. I want to mix this recording with a short sound clip and then create a new stream which is a mix of both the stream and then send it over a Datagram socket. I have researched a lot and here is what I came to know.

Firstly, SoundPool may help me achieve my goal, but I think I cannot provide Microphone as input source.

Currently I am saving the recording from MIC in a buffer and then streaming it over the datagram socket. I thought I can save the sound clip in another buffer and then add both the buffer(which I know is dumb a idea, as there are various properties of sound that I will have to manage).

Also may be I can save the recording from Microphone to a file and the recording of sound clip to a different file and mix them, however I think I cannot do this, as I am trying to stream the recording over the Datagram socket.

I think what I am trying to achieve may be possible using Java's sound API. But it is not supported by Android.

To summarize, what I am trying to achieve as my end goal is to inject a sound effect in a VoIP (SIP) based call (sound effect like crickets sound along with my voice).

I hope I gave a clear explanation about my problem.

Question 1: How can I achieve this? Question 2: Can I create a JAR file using Java's Sound API and use it in my project? (about this, I think it is not possible)

Here is some code of my Audio Recording and Audio Playback.

This is my code for audio recording:

            public void run() {
                // TODO Auto-generated method stub
                try{
                    int minbuffer = AudioRecord.getMinBufferSize(sample, config, format);
                    DatagramSocket socket = new DatagramSocket();
                    Log.d(TAG, "Socket Created");
                    socket.setBroadcast(true);
                    byte[] ubuff = new byte[minbuffer];

                    DatagramPacket packet;
                    Log.d(TAG, "Packet Created");
                    InetAddress dest = InetAddress.getByName("10.10.1.126");
                    //InetAddress dest = InetAddress.
                            //InetSocketAddress dest= new InetSocketAddress(host, port);
                    Log.d(TAG, "Address"+dest);

                    rec = new AudioRecord(MediaRecorder.AudioSource.MIC,sample,
                                config,format,minbuffer);

                    rec.startRecording();
                    while(status == true){

                        minbuffer = rec.read(ubuff, 0,ubuff.length);
                        Log.d(TAG, "Reading While");
                        packet = new DatagramPacket(ubuff, ubuff.length,dest,port);
                        socket.send(packet);
                    }
                }catch(Exception e){
                    Log.d(TAG, "Bad Datagram");
                }
            }
        });
        stream.start();     

This is my code for audio playback:

        @Override
        public void run() {
            // TODO Auto-generated method stub
            try{

                android.os.Process.setThreadPriority(Process.THREAD_PRIORITY_URGENT_AUDIO);
                AudioManager mm = (AudioManager)getSystemService(AUDIO_SERVICE);
                DatagramSocket rSocket = new DatagramSocket(8080);
                Log.d(TAG, "Recive Socket");

                int m_buf = AudioRecord.getMinBufferSize(sample, config, format);
                byte[] _buff = new byte[m_buf];
                AudioTrack rSpeaker = new AudioTrack(mm.STREAM_MUSIC,sample,config,
                            format,m_buf,AudioTrack.MODE_STREAM);
                mm.setSpeakerphoneOn(false);
                mm.setStreamVolume(AudioManager.STREAM_MUSIC, 100, AudioManager.MODE_IN_COMMUNICATION);
                Log.d(TAG, "zzRecorder");
                rSpeaker.setPlaybackRate(sample);
                rSpeaker.play();
                while(true){
                    try{
                        DatagramPacket rPacket = new DatagramPacket(_buff, _buff.length);
                        rSocket.receive(rPacket);
                        _buff = rPacket.getData();
                        rSpeaker.write(_buff, 0, m_buf);
                        Log.d(TAG, "Yo Start Write");
                    }catch(Exception e){

                    }
                }
            }catch(Exception e){

            }
        }
    });
    rvStrm.start();

Answer 1

EDIT - 31 Aug 2018

Source code forked at https://github.com/aksappy/jsresources-examples

I think this must be helpful to you,

http://www.jsresources.org/examples/AudioConcat.html

The link is an open source example for how to concatenate/mix audio files. I think the source that you will be most interested in will be

MixingAudioInputStream.java

http://www.jsresources.org/examples/MixingAudioInputStream.java.html

I do not know about the Support of Java Sound API, but AFAIK Java Sound API is for basic audio capture and playback. You will still have to do your own way of mixing, wouldnt you?

ATB