public void setVolume(float leftVolume, float rightVolume) {
        mVolumeLeft = leftVolume;
        mVolumeRight = rightVolume;

        if(mAudioPlayback != null) {
            mAudioPlayback.setStereoVolume(leftVolume, rightVolume);
        }
    }
@see android.media.MediaPlayer#setVolume(float, float)
MediaPlayer/src/main/java/net/protyposis/android/mediaplayer/MediaPlayer.java