Block diagram
Scream Tracker 3 module is a tracker music file format that, as all tracker music, bundles both sound samples and instructions on which notes to play. It originates from a Scream Tracker 3 music editor (1994) by Future Crew, derived from original Scream Tracker 2 (.stm) module format.
Instrument descriptions in S3M format allow to use either digital samples or setup and control AdLib (OPL2) synth.
Music is organized in so called patterns. "Pattern" is a generally
a 64-row long table, which instructs which notes to play on which
time measure. "Patterns" are played one-by-one in a sequence
determined by orders, which is essentially an array of pattern IDs
This page hosts a formal specification of Scream Tracker 3 module using Kaitai Struct. This specification can be automatically translated into a variety of programming languages to get a parsing library.
meta:
id: s3m
title: Scream Tracker 3 module
file-extension: s3m
xref:
justsolve: Scream_Tracker_3_module
pronom: fmt/718
wikidata: Q1461901
license: CC0-1.0
endian: le
doc: |
Scream Tracker 3 module is a tracker music file format that, as all
tracker music, bundles both sound samples and instructions on which
notes to play. It originates from a Scream Tracker 3 music editor
(1994) by Future Crew, derived from original Scream Tracker 2 (.stm)
module format.
Instrument descriptions in S3M format allow to use either digital
samples or setup and control AdLib (OPL2) synth.
Music is organized in so called `patterns`. "Pattern" is a generally
a 64-row long table, which instructs which notes to play on which
time measure. "Patterns" are played one-by-one in a sequence
determined by `orders`, which is essentially an array of pattern IDs
- this way it's possible to reuse certain patterns more than once
for repetitive musical phrases.
doc-ref: http://hackipedia.org/browse.cgi/File%20formats/Music%20tracker/S3M%2c%20ScreamTracker%203/Scream%20Tracker%203.20%20by%20Future%20Crew.txt
seq:
- id: song_name
size: 28
terminator: 0
- id: magic1
contents: [0x1a]
- id: file_type
-orig-id: Typ
type: u1
- id: reserved1
size: 2
- id: num_orders
-orig-id: OrdNum
type: u2
doc: Number of orders in a song
- id: num_instruments
-orig-id: InsNum
type: u2
doc: Number of instruments in a song
- id: num_patterns
-orig-id: PatNum
type: u2
doc: Number of patterns in a song
- id: flags
-orig-id: Flags
type: u2
- id: version
-orig-id: Cwt/v
type: u2
doc: Scream Tracker version that was used to save this file
- id: samples_format
-orig-id: Ffi
type: u2
doc: '1 = signed samples, 2 = unsigned samples'
- id: magic2
contents: 'SCRM'
- id: global_volume
-orig-id: g.v
type: u1
- id: initial_speed
-orig-id: i.s
type: u1
- id: initial_tempo
-orig-id: i.t
type: u1
- id: is_stereo
type: b1
- id: master_volume
-orig-id: m.v
type: b7
- id: ultra_click_removal
-orig-id: u.c
type: u1
- id: has_custom_pan
-orig-id: d.p
type: u1
- id: reserved2
size: 8
- id: ofs_special
-orig-id: Special
type: u2
doc: Offset of special data, not used by Scream Tracker directly.
- id: channels
type: channel
repeat: expr
repeat-expr: 32
- id: orders
size: num_orders
- id: instruments
type: instrument_ptr
repeat: expr
repeat-expr: num_instruments
- id: patterns
type: pattern_ptr
repeat: expr
repeat-expr: num_patterns
- id: channel_pans
type: channel_pan
repeat: expr
repeat-expr: 32
if: has_custom_pan == 252
types:
channel:
seq:
- id: is_disabled
type: b1
- id: ch_type
type: b7
doc: Channel type (0..7 = left sample channels, 8..15 = right sample channels, 16..31 = AdLib synth channels)
instrument_ptr:
seq:
- id: paraptr
type: u2
instances:
body:
pos: paraptr * 0x10
type: instrument
instrument:
seq:
- id: type
type: u1
enum: inst_types
- id: filename
terminator: 0
size: 12
- id: body
type:
switch-on: type
cases:
'inst_types::sample': sampled
_: adlib
- id: tuning_hz
type: u4
- id: reserved2
size: 12
- id: sample_name
size: 28
terminator: 0
- id: magic
contents: 'SCRS'
enums:
inst_types:
1: sample
2: melodic
3: bass_drum
4: snare_drum
5: tom
6: cymbal
7: hihat
types:
sampled:
seq:
- id: paraptr_sample
-orig-id: MemSeg
type: swapped_u3
- id: len_sample
-orig-id: Length
type: u4
- id: loop_begin
-orig-id: LoopBeg
type: u4
- id: loop_end
-orig-id: LoopEnd
type: u4
- id: default_volume
-orig-id: Vol
type: u1
doc: Default volume
- id: reserved1
type: u1
- id: is_packed
-orig-id: '[P]'
type: u1
doc: 0 = unpacked, 1 = DP30ADPCM packing
- id: flags
-orig-id: '[F]'
type: u1
instances:
sample:
pos: paraptr_sample.value * 0x10
size: len_sample
adlib:
# TODO
seq:
- id: reserved1
contents: [0, 0, 0]
- size: 16
pattern_ptr:
seq:
- id: paraptr
type: u2
instances:
body:
pos: paraptr * 0x10
type: pattern
pattern:
seq:
- id: size
type: u2
- id: body
size: size - 2
type: pattern_cells
pattern_cells:
seq:
- id: cells
type: pattern_cell
repeat: eos
pattern_cell:
seq:
- id: has_fx
type: b1
- id: has_volume
type: b1
- id: has_note_and_instrument
type: b1
- id: channel_num
type: b5
- id: note
type: u1
if: has_note_and_instrument
- id: instrument
type: u1
if: has_note_and_instrument
- id: volume
type: u1
if: has_volume
- id: fx_type
type: u1
if: has_fx
- id: fx_value
type: u1
if: has_fx
swapped_u3:
doc: Custom 3-byte integer, stored in mixed endian manner.
seq:
- id: hi
type: u1
- id: lo
type: u2
instances:
value:
value: lo | (hi << 16)
channel_pan:
seq:
- id: reserved1
type: b2
- id: has_custom_pan
type: b1
doc: |
If true, then use a custom pan setting provided in the `pan`
field. If false, the channel would use the default setting
(0x7 for mono, 0x3 or 0xc for stereo).
- id: reserved2
type: b1
- id: pan
type: b4