This program will take any "mpk" files in the current directory (from which it is run) and unpack them. I'm using it alongside my level editor so that in the end there is

                                    ` This code was downloaded from The Game Creators
                                    ` It is reproduced here with full permission
                                    ` http://www.thegamecreators.com
                                    
                                    Rem Project: MediaPacker
Rem Created: 6/12/2004 8:08:06 PM

Rem ***** Main Source File *****
dim files$(256)
dim filetypes(256)
dim sizes(256)
dim sizebytes(4)
dim tocoffsets(256)
dim toctemp(4)
dim offsetbyte(4)
dim offsettemp(4)

directory$=get dir$()
unpackmedia(directory$)


function unpackmedia(packdir$)
set dir packdir$
find first
repeat
if get file type()=0 and right$(get file name$(),3)="mpk"
   foundfiles=foundfiles+1
   files$(foundfiles)=get file name$()
   sizes(foundfiles)=file size(files$(foundfiles))
endif
find next
until get file type()=-1
foundblocks=0
for unpack=1 to foundfiles
   if file exist(files$(foundfiles))=1 then open to read 1, files$(foundfiles)
   skip bytes 1,8
   for toc=1 to 256
      read byte 1, null
      read byte 1, null
      read byte 1, temp1
      read byte 1, temp2
      read byte 1, temp3
      read byte 1, temp4
      read byte 1, null
      read byte 1, null
      offsetbyte(1)=temp1
      offsetbyte(2)=temp2
      offsetbyte(3)=temp3
      offsetbyte(4)=temp4
      temp$=setdecimaloffset()
      tocoffsets(toc)=db2d(temp$)
   next toc
   for toc=1 to 255
      if tocoffsets(toc)<>0 then extractfileblock(toc)
   next toc
   close file 1
next unpack
endfunction

function setdecimaloffset()
32bits$=""
for d=1 to 4
   temp=offsetbyte(d)
   32bits$=32bits$+d2b(temp)
next d
endfunction 32bits$

function getcorrectchar(filename$,m)
if m>len(filename$)
   returnascii=asc("%")
else
   returnascii=asc(mid$(filename$,m))
endif
endfunction returnascii

function db2d(bits$)
total=0
for bit=1 to 32
   bit$=mid$(bits$,bit)
   if bit$="1" then total=total + (2^(32-bit))
next newbit
rem debug(str$(total))
endfunction total

function d2b(decimal)
8bits$=""
for b=7 to 0 step -1
   if decimal>=(2^b)
      bit$="1"
      decimal=decimal-(2^b)
   else
      bit$="0"
   endif
8bits$=8bits$+bit$
next b
endfunction 8bits$


function debug(variable$)
cls
do
   text 1,1,variable$
   sync
   if spacekey()=1 then exit
loop
do
if spacekey()=0 then exit
loop
text 1,1,variable$
sync
endfunction

function extractfileblock(toc)
read byte 1, null
read byte 1, null
read byte 1, null
read byte 1, null
read byte 1, temp1
read byte 1, temp2
read byte 1, temp3
read byte 1, temp4
offsettemp(1)=temp1
offsettemp(2)=temp2
offsettemp(3)=temp3
offsettemp(4)=temp4
temp$=getdecimaloffset()
filelength=db2d(temp$)
filename$=""
rem ####################################################################################
for b=1 to 32
   read byte 1, byt
   if chr$(byt)<>"%" then filename$=filename$+chr$(byt)
next b
rem debug(filename$)
read byte 1, null
read byte 1, null
if file exist(filename$)=1 then delete file filename$
open to write 2, filename$
for wnfbbb=1 to filelength
   read byte 1, tempp
   write byte 2, tempp
next wnfbbb
close file 2
endfunction

function getdecimaloffset()
32bits$=""
for d=1 to 4
   temp=offsettemp(d)
   32bits$=32bits$+d2b(temp)
next d
endfunction 32bits$