# Recipe 65: Double the frequency of a sound

def double(filename):
  source = makeSound(filename)
  target = makeSound(filename)
  #target = makeEmptySound(int(getLength(source)/getSamplingRate(source)))

  targetIndex = 1
  for sourceIndex in range(1, getLength(source)+1, 2):
    setSampleValueAt( target, targetIndex, getSampleValueAt( source, sourceIndex))
    targetIndex = targetIndex + 1

  # Clear out the rest of the target sound -- it's only half full!
  for secondHalf in range( getLength( target)/2, getLength( target)):
    setSampleValueAt(target,targetIndex,0)
    targetIndex = targetIndex + 1

  play(target)
  return target