code: func PCMScale(buf *audio.PCMBuffer) error {
  	if buf == nil || buf.Format == nil {
  		return audio.ErrInvalidBuffer
  	}
  	buf.SwitchPrimaryType(audio.Float)
  	factor := float64(audio.IntMaxSignedValue(buf.Format.BitDepth))
  	for i := 0; i < buf.Len(); i++ {
  		buf.Floats[i] *= factor
  	}
  
  	return nil
  }
docs: // PCMScale converts a buffer with audio content from -1 to 1 into
  // the PCM scale based on the buffer's bitdepth.