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Large Pack of OldSkool DOS MOD Trackers
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FORMAT.TXT
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1995-03-02
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╒════════════════════════════════════════════════════════════════════════════╕
├────────────────────────────────────────────────────────────────────────────┤
│ │
│ DIGITRAKKER FILE-FORMAT INFORMATION by proton/n-Factor │
│ │
├────────────────────────────────────────────────────────────────────────────┤
╘════════════════════════════════════════════════════════════════════════════╛
This file contains information about the songmodule-format "MDL" and the
sample-format "SPL". If you have some problems or if you have questions about
these formats, which are not answered in here, just contact me.
╔════════════════════════════════════════════════════════════════════════════╗
║ THE SONGMODULE-FORMAT (MDL) V000 ║
╚════════════════════════════════════════════════════════════════════════════╝
Offset Lenght Description
000 004 "DMDL"; the four letters mark the mdl-format
004 001 version; the current version is 0
005 ??? the different data-blocks are stored at this position
The MDL-songmodule-format is subivided into the following blocks:
"IN" - infoblock; contains most songparameters, like speed, length etc.
"PN" - patternnames; contains the names of the pattern
"ME" - songmessage; contains the songinformation from the composer
"PA" - pattern; contains the tracklists for every pattern
"TR" - tracks; contains the different tracks for the pattern
"IS" - instruments; contains information for every used sample
"SA" - samples; contains the sample-datas
The sequence of the blocks in a file is not fixed so they can be stored in any
way. Digitrakker uses the descripted sequence.
The structure for every block is the same:
Offset Lenght Description
000 002 "xx"; block-ID (example: "IN" for infoblock)
002 004 blocklength; this dword contains the length of the following
datas.
006 <blocklen> datas for this block...
The next block will be at offset (006 + <blocklength>).
┌────────────────────────────────────────────────────────────────────────────┐
│ The Infoblock (IN) │
└────────────────────────────────────────────────────────────────────────────┘
Offset Lenght Description
000 002 "IN"; infoblock-ID
002 004 blocklenght
006 032 songname; name of the songmodule (filled with spaces [32])
038 020 composername; name of the song-composer
058 002 songlength; Digitrakker supports up to 255 songpositions
060 002 songrepeat
062 001 mainvolume (001-255)
063 001 song-speed (001-255)
064 001 beats per minute (004-255)
065 032 channel-information: bit 0-6 - panposition (0=left,127=right)
bit 7 - 0=channel on, 1=channel off
097 <snglen> sequencer; contains the number of the pattern for every
songposition
??? <chnnam> the names for every channel (8 chars for one name).
<chnnam> = 8 * <number of channels>
┌────────────────────────────────────────────────────────────────────────────┐
│ The Patternnames (PN) │
└────────────────────────────────────────────────────────────────────────────┘
Offset Lenght Description
000 002 "PN"; patternnames-ID
002 004 blocklenght
006 <patnam> the names for every pattern (16 chars for one name).
<patnam> = 16 * <number of patterns>
┌────────────────────────────────────────────────────────────────────────────┐
│ The Songmessage (ME) │
└────────────────────────────────────────────────────────────────────────────┘
Offset Lenght Description
000 002 "ME"; songmessage-ID
002 004 blocklenght
006 ??? songmessage; every line is closed with the CR-char (13). A
0-byte stands at the end of the whole text.
┌────────────────────────────────────────────────────────────────────────────┐
│ The Patterndatas (PA) │
└────────────────────────────────────────────────────────────────────────────┘
Offset Lenght Description
000 002 "PA"; patterndata-ID
002 004 blocklenght
006 001 number of pattern; values from 1 to 255 are possible
007 <patlar> tracksequencing-data for the used patterns;
These sequencer-lists descripe which track is used as which voice in each
saved pattern. Every pattern consists of 32 channels. The first word in this
list is the number of the track at pattern 0, voice 0. The second is track for
pattern 0, voice 1 and so on... As every pattern consists of 32 voices
(channels), the tracksequencing-list needs 32 words = 64 bytes.
<patlar> = 64 * <number of patterns>.
As every track is saved independend, it is possible to save some discspace by
this methode: If the song contains equal tracks at several positions in
the patterns, these double tracks will only saved one time.
Track 0 is not saved and represents an empty track.
┌────────────────────────────────────────────────────────────────────────────┐
│ The Trackdatas (TR) │
└────────────────────────────────────────────────────────────────────────────┘
Offset Lenght Description
000 002 "TR"; trackdata-ID
002 004 blocklenght
006 002 number of tracks
008 ??? track-datablocks; every trackdatablock is stored in this way:
Ofs.000 Len.002 length of the trackdatas
002 <trackdatalen> datas for this track
Every track consists of 64 notepositions and every notposition contains 6
bytes:
byte 0 - note-value; 1=C-0,2=C#0,...,120=B-9,0=nothing,255=stopper
byte 1 - sample-number; 1-255; 0=nothing
byte 2 - volume; 1-255; 0=no volume change
byte 3, low nibble - number of the first effect-command
byte 3, high nibble - number of the second effect-command
byte 4 - databyte for the first effect-command
byte 5 - databyte for the second effect-command
So one track needs 6 * 64 = 384 bytes in the memory. Digitrakker stores the
tracks in a packed way. The structure of this (very effective!) packformat is
the following:
bit 76543210
byte 0 - xxxxxxyy
if yy = 00 -> <xxxxxx>+1 is the number of the empty notepositions which are
following.
if yy = 01 -> the last noteposition will be repeated <xxxxxx>+1 times.
if yy = 10 -> the noteslot from position <xxxxxx> is copied to the actual
position.
if yy = 11 -> the following datas will be put in the actual noteslot:
bit 2 = 1 -> note
bit 3 = 1 -> sample
bit 4 = 1 -> volume
bit 5 = 1 -> effectcommand numbers
bit 6 = 1 -> databyte for effect 1
bit 7 = 1 -> databyte for effect 1
┌────────────────────────────────────────────────────────────────────────────┐
│ The Instrument-Infoblock (IS) │
└────────────────────────────────────────────────────────────────────────────┘
Offset Lenght Description
000 002 "IS"; intrumentinfo-ID
002 004 blocklenght
006 001 number of samples; vales from 0 to 255 are possible
007 <inslar> instrument-datas; the datablock for an instrument contains
57 bytes, so <inslar> = 57 * number of saved samples
The structure of one instrument-datablock:
000 001 sample-number; (1-255)
001 032 sample-name; the name of the sample (filled with [32])
033 008 filename of the sample
041 002 C-4 sample-frequence in hz (00000-65535)
043 004 sample-length
047 004 sample-repeatstart
051 004 sample-repeatlength; if this value is set to 0, the sample
will not loop
055 001 sample-volume (001-255)
056 001 infobyte:
bit 0 -> 0=8 bit sample, 1=16 bit sample
bit 1 -> 0=forward looping, 1=bidirectional looping
bit 2,3 -> packmethode (0=not packed, methodes 2 and 3 doesn't
exist in this version)
bit 4-7 -> not used (should be set to 0)
┌────────────────────────────────────────────────────────────────────────────┐
│ The Sampledatas (SA) │
└────────────────────────────────────────────────────────────────────────────┘
Offset Lenght Description
000 002 "SA"; sampledata-ID
002 004 blocklenght
006 ??? sampledatas; samples are stored in numeric sequence
Unpacked samples are stored in signed form. Packmethode (1) only works with
8 bit samples, so 16 bit samples will always be unpacked.
The description of the sample-packmethode (1):...
This methode is based on the huffman-algorithm. It's an easy form, but very
fast and effective on samples. The packed sample is a bit-data-stream:
Byte 0 Byte 1 Byte 2 Byte 3
Bit 76543210 fedcba98 nmlkjihg ....rqpo
A packed byte is stored in the following form:
xxxx10..0s => byte = <xxxx> + (number of <0>-bits between s and 1) * 16 - 8 ;
if s=1 then byte = byte xor 255
If there are no <0>-bits between the first bit (sign) and the <1>-bit, you
have the following form:
xxx1s => byte = <xxx> ; if s=1 then byte = byte xor 255
To depack one byte, you have to use the following algorithm:
┌────────────────────────────────────────────────────────────────────────────┐
│ read bit │
│ sign = bit │
│ read bit │
│ if bit = 1 │
│ then read [3bits] │
│ byte = [3bits] │
│ goto next │
│ else byte = 8 │
│loop: read bit │
│ if bit = 0 │
│ then byte = byte + 16 │
│ goto loop │
│ else read [4bits] │
│ byte = byte + [4bits] │
│next: if sign = 1 │
│ then byte = byte xor 255 │
└────────────────────────────────────────────────────────────────────────────┘
Two examples:
xxxx s
1001101 = ( 9 + 1 * 16 - 8 ) xor 255 = 238
xxx s
01010 = 2
Note that the depacked bytes are delta values. To convert them to real data
use this algorithm:
oldbyte = 0
for sampleposition = 1 to samplelength
newbyte = byte [sampleposition] + oldbyte
byte [sampleposition] = newbyte
oldbyte = newbyte
next sampleposition
╔════════════════════════════════════════════════════════════════════════════╗
║ THE SAMPLE-FORMAT (SPL) V000 ║
╚════════════════════════════════════════════════════════════════════════════╝
Offset Lenght Description
000 004 "DSPL"; the four letters mark the spl-format
004 001 version; the current version is 0
005 032 sample-name; the name of the sample (filled with [32])
037 008 filename of the sample
045 002 C-4 sample-frequence in hz (00000-65535)
047 004 sample-length
051 004 sample-repeatstart
055 004 sample-repeatlength; if this value is set to 0, the sample
will not loop
059 001 sample-volume (001-255)
060 001 infobyte:
bit 0 -> 0=8 bit sample, 1=16 bit sample
bit 1 -> 0=forward looping, 1=bidirectional looping
bit 2,3 -> packmethode (0=not packed, methodes 2 and 3 doesn't
exist in this version)
bit 4-7 -> not used (should be set to 0)
061 ??? sampledatas... (see above)