I can't change the speed of a music file without avoiding that a disturbing noise appear

Question

I am trying to change the speed of an audio file, if I do it with unsigned values all is all right, but once I start using double values things get messy, for instance, my code

Answer 1

Your reading-from falls on odd barriers: that is because of truncation the read-from byte starts at an odd location. Use the following to start from even location:

for (i=0; i<(b2.length/frameSize); i++) {
      int ind=(int)((i*frameSize*playBackSpeed));
      if((ind%2)==1) ind++;
    for (j=0; j<frameSize; j++) {
        b2[(i*frameSize)+j] = b1[ind+j];
    }
}

Or you can change the jump to 4:

    if((ind%4)>0) ind+=(4-(ind%4));