ProtrackerFileFormat
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
Back to Music