ProtrackerFileFormat

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Protracker 1.1B Song/Module Format:

Offset Bytes Description

  0     20    Songname. Remember to put trailing null bytes at the end...

Information for sample 1-31:

Offset Bytes Description

 20     22    Samplename for sample 1. Pad with null bytes.
 42      2    Samplelength for sample 1. Stored as number of words.
              Multiply by two to get real sample length in bytes.
 44      1    Lower four bits are the finetune value, stored as a signed
              four bit number. The upper four bits are not used, and
              should be set to zero.
              Value:  Finetune:
                0        0
                1       +1
                2       +2
                3       +3
                4       +4
                5       +5
                6       +6
                7       +7
                8       -8
                9       -7
                A       -6
                B       -5
                C       -4
                D       -3
                E       -2
                F       -1

 45      1    Volume for sample 1. Range is $00-$40, or 0-64 decimal.
 46      2    Repeat point for sample 1. Stored as number of words offset
              from start of sample. Multiply by two to get offset in bytes.
 48      2    Repeat Length for sample 1. Stored as number of words in
              loop. Multiply by two to get replen in bytes.

Information for the next 30 samples starts here. It's just like the info for sample 1.

Offset Bytes Description

 50     30    Sample 2...
 80     30    Sample 3...
  .
  .
  .
890     30    Sample 30...
920     30    Sample 31...

Offset Bytes Description

950      1    Songlength. Range is 1-128.
951      1    Well... this little byte here is set to 127, so that old
              trackers will search through all patterns when loading.
              Noisetracker uses this byte for restart, but we don't.
952    128    Song positions 0-127. Each hold a number from 0-63 that
              tells the tracker what pattern to play at that position.

1080 4 The four letters "M.K." - This is something Mahoney & Kaktus

              inserted when they increased the number of samples from
              15 to 31. If it's not there, the module/song uses 15 samples
              or the text has been removed to make the module harder to
              rip. Startrekker puts "FLT4" or "FLT8" there instead.

Offset Bytes Description 1084 1024 Data for pattern 00.

  .
  .
  .

xxxx Number of patterns stored is equal to the highest patternnumber

     in the song position table (at offset 952-1079).

Each note is stored as 4 bytes, and all four notes at each position in the pattern are stored after each other.

00 - chan1 chan2 chan3 chan4 01 - chan1 chan2 chan3 chan4 02 - chan1 chan2 chan3 chan4 etc.

Info for each note:

_____byte 1_____   byte2_    _____byte 3_____   byte4_

/ / / / 0000 0000-00000000 0000 0000-00000000

Upper four 12 bits for Lower four Effect command. bits of sam- note period. bits of sam- ple number. ple number.

Periodtable for Tuning 0, Normal

 C-1 to B-1 : 856,808,762,720,678,640,604,570,538,508,480,453
 C-2 to B-2 : 428,404,381,360,339,320,302,285,269,254,240,226
 C-3 to B-3 : 214,202,190,180,170,160,151,143,135,127,120,113

To determine what note to show, scan through the table until you find the same period as the one stored in byte 1-2. Use the index to look up in a notenames table.

This is the data stored in a normal song. A packed song starts with the four letters "PACK", but i don't know how the song is packed: You can get the source code for the cruncher/decruncher from us if you need it, but I don't understand it; I've just ripped it from another tracker...

In a module, all the samples are stored right after the patterndata. To determine where a sample starts and stops, you use the sampleinfo structures in the beginning of the file (from offset 20). Take a look at the mt_init routine in the playroutine, and you'll see just how it is done.

Lars "ZAP" Hamre/Amiga Freelancers


Found that document...

Mark J Cox ------------------------------------------- m.j.h.cox@bradford.ac.uk
University of Bradford ---------------------------- bc732@cleveland.freenet.edu

Mark



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