#
# Praat Script: RE-QUANTISATION
#
# This program changes the quantisation rate of a sound file. 
# Important advice: runtime per 1 second of sound file is appr. 5 sec. 
# i.e. long files can take a long time to be processed. It is recommended
# to use it for short files only.
#
#                                               written by Floki
#
#

### Create user interface window ################################################

form Floki's waveform re-quantisation
   comment Finding the file you want to re-quantise
   comment Please specify the path:
      text Path C:\Dokumente und Einstellungen\Flok\Desktop\
   comment Please specify the filename:
      text Filename quantiseTest.wav
   comment ----------------------------------------------------------------------------------------------------------------------   
   comment Please specify the quantisation rate of your sine wave in bit:
      optionmenu quantisation_rate: 1
         option 16 bit
         option 12 bit
         option  8 bit
         option  4 bit
         option  2 bit
         option  1 bit
endform

### Read file and change its quantisation level #################################

Read from file... 'path$''filename$'
filename$ = filename$-".wav"
Down to Matrix

if quantisation_rate = 1
   bitLevel$ = "_16bit"
elsif quantisation_rate = 2
   quantisation = 2048
   bitLevel$ = "_12bit"
   call changeBitRate
elsif quantisation_rate = 3
   quantisation = 128
   bitLevel$ = "_8bit"
   call changeBitRate
elsif quantisation_rate = 4
   quantisation = 8
   bitLevel$ = "_4bit"
   call changeBitRate
elsif quantisation_rate = 5
   quantisation = 2
   bitLevel$ = "_2bit"
   call changeBitRate
elsif quantisation_rate = 6
   quantisation = 1
   bitLevel$ = "_1bit"
   call changeBitRate
endif

procedure changeBitRate
select Sound 'filename$'
numberOfSamples = Get number of samples
   for i to numberOfSamples
      x = Get value at index... 'i'
      x = floor(x*quantisation)/quantisation
      Set value at index... 'i' 'x'
   endfor
endproc

### Final adjustments ###########################################################

select Matrix 'filename$'
Remove
select Sound 'filename$'
Rename... 'filename$''bitLevel$'