Play 2 different audio streams on left and right speaker

Question

Some special circumstances force me to do that perverted thing.

Is it possible to play 2 different audio streams on different channels. Imagine a headset and I need to play 1st song at left speaker and 2nd song on right speaker simultaneously.

After some research I found that it is possible to play at some single channel. Its possible even to close one of them. But I didn't find any information how to play 2 audio streams simultaneously.

Is it even possible? And how? Some code examples and links appreciated!

---

Research results.

1)AudioTrack able to play on different channels

// only play sound on left
for(int i = 0; i < count; i += 2){
    short sample = (short)(Math.sin(2 * Math.PI * i / (44100.0 / freqHz)) * 0x7FFF);
    samples[i + 0] = sample;
    samples[i + 1] = 0;
}
// only play sound on right
for(int i = 0; i < count; i += 2){
    short sample = (short)(Math.sin(2 * Math.PI * i / (44100.0 / freqHz)) * 0x7FFF);
    samples[i + 0] = 0;
    samples[i + 1] = sample;
}

2) SoundPool able to set volume for left and right channels separately. So technically it's possible to start 2 streams and set for one 0 left volume and 100 for right volume and vice versa for 2nd stream. Right?

setVolume(int streamID, float leftVolume, float rightVolume)

sample:

    SoundPool pool = new SoundPool(1, AudioManager.STREAM_NOTIFICATION, 0);
pool.play(
        pool.load(this, R.raw.my_sound_effect, 1), // The sound effect to play
        0, // The volume for the left channel (0.0 - 1.0)
        1.0f, // The volume for the right channel (0.0 - 1.0)
        0, // Default priority 
        0, // Do not loop
        1.0f); // Playback rate (1.0f == normal)

Perhabs there's such solution using MediaPlayer so that would be much preferable!

---

SOLUTION: Seems like the easiest solution is to use SoundPool. The way I tested it.

//SDK Version
public CustomSoundPool() {
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
        AudioAttributes attributes = new AudioAttributes.Builder()
                .setUsage(AudioAttributes.USAGE_GAME)
                .setContentType(AudioAttributes.CONTENT_TYPE_SONIFICATION)
                .build();

        soundPool = new SoundPool.Builder()
                .setAudioAttributes(attributes)
                .build();
    } else {
        soundPool = new SoundPool(10, AudioManager.STREAM_MUSIC, 0);
    }
    soundPool.setOnLoadCompleteListener(new SoundPool.OnLoadCompleteListener() {
        @Override
        public void onLoadComplete(SoundPool soundPool, int sampleId, int status) {
            soundPool.play(sampleId, 1.0f, 0, 0, 0, 1.0f); //left channel
            //soundPool.play(sampleId, 0, 1.0f, 0, 0, 1.0f); //right channel
        }
    });
}

public void playSound(String path) {
    if (soundPool != null) {
        soundPool.load(path, 1);
    }
}

public void release(){
    if (soundPool != null) {
        soundPool.release();
    }
}

Although there's lack of features like MediaPlayer.OnCompletionListener(). Now sure how to implement this but anyway.. Problem solved.

Answer 1

I used 2 instances of mediaplayer and tried to play two seperate music tracks on earphones and it worked like a charm. it played one track on the left and an another on the right.

MediaPlayer mediaPlayer1 = MediaPlayer.create(this, R.raw.lenka);
MediaPlayer mediaPlayer2 = MediaPlayer.create(this, R.raw.faded);
final int sessionIdA = mediaPlayer1.getAudioSessionId();
final int sessionIdB = mediaPlayer2.getAudioSessionId();
mediaPlayer1.setLooping(true);
mediaPlayer2.setLooping(true);
mediaPlayer1.setVolume(0, 1);
mediaPlayer2.setVolume(1, 0);
mediaPlayer1.start();
mediaPlayer2.start();