Change The Playback Rate Of A Track In Real Time On Android

I would like to know if somebody knows a library to changing the playback rate of a track in real time. My idea is to load a track and change its playback rate to half or double. F

Solution 1:

you call sp.play once, at the time that function is called the value of j is copied into that function.

Changing j afterward doesn't change the value of j in the function (this is called pass by value)

To change the rate of play afterward you need to call sp.setRate(StreamID,j) within your button click listener.

Note that the StreamID is returned by the sp.play function, so store this as a variable in the class.

This code should work ( i didn't test it):

floatj=1.0f;
SoundPoolsp=null;
intsID=0;

@OverridepublicvoidonCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    Buttonb= (Button)findViewById(R.id.Button01);
    b.setOnClickListener(newOnClickListener() {

        @OverridepublicvoidonClick(View v) {
            j = (float) (j +.5f);
            sp.setRate(sID,j);

        }
    });

    AssetFileDescriptor afd;
    try {

        sp = newSoundPool(1, AudioManager.STREAM_MUSIC, 0);

        afd = getAssets().openFd("wav/sample.wav");
        intid= sp.load(afd, 1);
        sID = sp.play(id, 1, 1, 1, 0, j);

    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
}

although it will probably crash after a couple button presses, SoundPool only supports rates from 0.5 to 2.0. You should add checking to make sure j stays within those bounds.