pro make_difference_mpeg, y_low=y_low,y_high=y_high,x_low=x_low,x_high=x_high,$
	Shack_Directory=Shack_Directory,letter=letter,begin_file=begin_file,$
	end_file=end_file

If (not keyword_set(Shack_Directory)) then Shack_Directory='/a/pippin01/Volumes/u08/lsst/CPanalysis/2005-05-10/ShackHartman/'
If (not keyword_set(letter)) then letter=['a']
If (not keyword_set(pixels)) then pixels='whole_array'
If (not keyword_set(y_low)) then y_low=140
If (not keyword_set(y_high)) then y_high=780
If (not keyword_set(x_low)) then x_low=220
If (not keyword_set(x_high)) then x_high=860
If (not keyword_set(begin_file)) then begin_file=1
If (not keyword_set(end_file)) then end_file=99

Raw_dir=Shack_Directory+'raw/'
Shift_dir=Shack_Directory+'shifted/'

letters=N_elements(letter)
num_of_files=100

;NAME OF MOVIE
mpegname=Shack_directory+'mpegs/hr5132'+letter(0)+'_'+$
         strtrim(begin_file,2)+'_'+strtrim(end_file,2)+'.mpg'

diff_movie=mpeg_open([768,768],quality=80)
frame_no=0
no_frames_per_image=15

;SET PLOT TO BUFFER SO THAT OTHER PROCESSES CAN OCCUR WHILE MOVIE IS MADE
set_plot,'Z'

for letter_ind=0,letters-1 do begin

        for file_number=begin_file,end_file do begin

	shifted_filename=shift_dir+letter(0)+'_'+strtrim(begin_file,2)+$
	'-'+strtrim(end_file,2)+'/hr5132'+letter(0)+'_'+$
	strtrim(file_number,2)+'_shifted.fits'
	
	unshifted_filename=raw_dir+'/hr5132'+letter(0)+'_'+$
	strtrim(file_number,2)+'_raw.fits'

	;jpegname=shift_dir+letter(0)+'_'+strtrim(begin_file,2)+$
	;'-'+strtrim(end_file+1,2)+'/hr5132'+letter(0)+'_'+$
	;strtrim(file_number,2)+'_diff.jpg'
	
	print,FORMAT='(%"%s\t\t%d")',letter(letter_ind),file_number

	fits_read,shifted_filename,shifted_image
	fits_read,unshifted_filename,unshifted_image

	shifted_image=shifted_image(x_low:x_high,y_low:y_high)
	unshifted_image=unshifted_image(x_low:x_high,y_low:y_high)

	;SET UP REFERENCE LINE
	x=x_low+findgen(x_high-x_low)
	y=fltarr(x_high-x_low)+468


	plot,x,y,xrange=[x_low,x_high],yrange=[y_low,y_high],position=[0,0,1,1],$
        thick=.2,xstyle=11,ystyle=11
        axes=tvrd()
	axes=congrid(axes,768,768)

	shifted_image=bytscl(shifted_image,min=20,max=5000)
	shifted_image=congrid(shifted_image,768,768)
	unshifted_image=bytscl(unshifted_image,min=20,max=5000)
	unshifted_image=congrid(unshifted_image,768,768)
	shifted_image(where(shifted_image gt 30))=255
	unshifted_image(where(unshifted_image gt 30))=255

	image1=fltarr(3,768,768)
	image1(0,*,*)=shifted_image
	image1(1,*,*)=unshifted_image
	image1(2,*,*)=axes
	
	;tv,image1,true=1
	

	for i=0, no_frames_per_image do begin
		mpeg_put,diff_movie,IMAGE=image1,$
			 frame=(frame_no*no_frames_per_image+i),$
			 /order
	endfor


	;write_jpeg,jpegname,image1,quality=100,true=3

	frame_no=frame_no+1

	endfor

endfor

mpeg_save,diff_movie,FILENAME=mpegname
mpeg_close,diff_movie

end