(Excerpt from documentation by Bernard Jungen and Gil Damoiseaux)


   Archimedes Tracker V1.0+++ File Formats
   ---------------------------------------
    
     Module format
     -------------

     This is the format of a Tracker module file (Filetype &CB6).

       Field length Contents
       ------------ --------
          4 bytes   The string "MUSX"
          4 bytes   Chunk length (i.e. total size -8)
          4 bytes   The string "TINF"
          4 bytes   Value 4
          4 bytes   Date of version in BCD format: YYYYMMDD (bytes 1 to 4)
          4 bytes   The string "MVOX"
          4 bytes   Value 4
          4 bytes   Number of voices (1-8)
          4 bytes   The string "STER"
          4 bytes   Value 8
          8 bytes   Default stereo positions for 8 channels. See the command.
          4 bytes   The string "MNAM"
          4 bytes   Tune name length (32)
         32 bytes   Tune name padded with zero's
          4 bytes   the string "ANAM"
          4 bytes   Author name length (32)
         32 bytes   Author name padded with zero's
          4 bytes   the string "MLEN"
          4 bytes   Value 4
          4 bytes   Tune length (1-128)
          4 bytes   the string "PNUM"
          4 bytes   Value 4
          4 bytes   Number of defined patterns (1-64)
          4 bytes   the string "PLEN"
          4 bytes   Value 64
         64 bytes   Length of each pattern (0-64)
          4 bytes   the string "SEQU"
          4 bytes   Value 128
        128 bytes   pattern number to be played at each position (0-63) 

       This is followed by a pattern chunk for each defined pattern.
       After that, there is a sample chunk for each of the 36 samples. 
       Note that such a file can contain more than one module (MUSX chunk)
       but practically it's very rare and not easy to handle... 
       Such a format for a music module is a bit silly since nearly all
       chunks have a constant length.


     Pattern chunk format
     --------------------

     This is the component of a Tracker pattern file (Filetype &FF1).
    
       Field length Contents
       ------------ --------
          4 bytes   The string "PATT"
          4 bytes   Chunk length (i.e. number of voices * 256 - the manual
                    says it's always 2048, that's false! ): xx
         xx bytes   Notes 

         Each note is stored as 4 bytes, and all x notes at each position in
         the pattern are stored after each other.
    
         Position         Notes data
         -------- ---------------------------
            00    chan 1  chan 2  ...  chan x
            01    chan 1  chan 2  ...  chan x
            02    chan 1  chan 2  ...  chan x

           etc. 

         Info for each note:
         -------------------     

         bits 24-31: note number (0-36).
              16-23: sample number (0-36).
               8-15: effect command number.
               0- 7: effect value (0-255).
    
         Note numbers table:
         -------------------
           C-1 to B-1 : 01 to 12
           C-2 to B-2 : 13 to 24
           C-3 to B-3 : 25 to 36 


     Sample chunk format
     -------------------

     This is the component of a Tracker sample file (Filetype &CB5).

       Field length Contents
       ------------ --------
          4 bytes   The string "SAMP"
          4 bytes   Chunk length (i.e. total size -8)
          4 bytes   The string "SNAM"
          4 bytes   Sample name length (20)
         20 bytes   Sample name padded with zero's
          4 bytes   The string "SVOL"
          4 bytes   Value 4
          4 bytes   Sample volume (0-255). Logarithmic
          4 bytes   The string "SLEN"
          4 bytes   Value 4
          4 bytes   Sample length (multiple of 4 otherwise Tracker crashes!)
          4 bytes   The string "ROFS"
          4 bytes   Value 4
          4 bytes   Repeat offset
          4 bytes   The string "RLEN"
          4 bytes   Value 4
          4 bytes   Repeat length
          4 bytes   The string "SDAT"
          4 bytes   Sample length (multiple of 4): xx
         xx bytes   Sample data in logarithmic format 

       Note: the manual states that not all sub-chunks may be present. But
             until now they've always been there. 


   Archimedes Tracker V1.0+++ Effect Commands
   ------------------------------------------                   

     (x-y,z) indicates z is done if value not in the range x to y.
     <command character> <command number in hex> <effect value in hex> 

     0 00 xy Normal play or Arpeggio.
             x: first halfnote to add
             y: second halftone to subtract 

     1 01 xx Slide Up.
             xx: pitch increase step (4 bits?) 

     2 02 xx Slide Down.
             xx: pitch decrease step (4 bits?)

     B 0B xx Break Pattern. 

     E 0E xy Set Stereo.
             y: stereo position (1-7,ignored). 1=left 4=center 7=right

     G 10 xx Volume Slide Up.
             xx: speed (4 bits?) 

     H 11 xx Volume Slide Down.
             xx: speed (4 bits?) 

     J 13 xx Position Jump.
             xx: song position (0-127,masked) 

     L 15 xy Line Jump. (not in manual)
             Jump to line 10*x+y in same pattern. (10*x+y>63 ignored) 

     S 1C xy Set Speed.
             y: speed (1-15,ignored) 

     V 1F xx Set Volume.
             xx: volume (0-255). Logarithmic.