OpenMPT manual — Effect Reference

The complete command table of openmpt for every format it writes — MOD, XM, S3M, IT and its own MPTM — with the effect-memory rules, the oscillator waveforms, the retrigger volume table and the "sound control" sub-commands, and with every non-original command marked as a ModPlug hack. Because OpenMPT documents each format's original semantics, this one page is also the best cross-reference between ProTracker/FastTracker letters and Scream Tracker/Impulse Tracker letters (effect-command-crosswalk).

Key claims#

• Notation: effect-column letters are uppercase with hexadecimal parameters, volume-column letters lowercase with decimal parameters. xx is one 8-bit value, xy two nibbles. MOD and XM share one command set, S3M/IT/MPTM another ("F75 in MOD turns into T75 in S3M"). Out-of-range parameters (e.g. Cxx above 40h) are discouraged.
• Frequency units: with Linear Frequency Slides on, a slide unit is 1/16 semitone and an extra-fine unit 1/64 (IT/MPTM); otherwise a unit is one period (period = 3,546,895 ÷ frequency; 3,579,364 in XM), so slides move less at low pitches and more at high ones. MOD and S3M never use linear slides.
• Waveforms for vibrato, tremolo and panbrello: S3M/IT/MPTM 0 sine, 1 sawtooth, 2 square, 3 random (all retrigger); MOD/XM add 4–7 = the same waveforms continued across notes. Every waveform is 64 points long and the speed parameter is points per tick (speed 2 repeats after 32 ticks). Random is "not supported by ProTracker and FastTracker" — avoid it in MOD/XM.
• Retrigger volume (Rxy in XM, Qxy in S3M/IT): x = 0 last value (XM) / no change (S3M, IT), 1–5 −1, −2, −4, −8, −16, 6 ×⅔, 7 ×½, 8 none, 9–D +1 … +16, E ×1.5, F ×2.
• Sound control (X9x in XM, S9x in S3M/IT): 0/1 surround off/on (only S91 is native to IT), 8/9 reverb off/on (discouraged), A/B centre / quad surround, C/D global / local filters (Z7F + Z80 switch a global filter off), E/F play forward / backward. Outside MPTM these are ModPlug hacks.
• MOD (effect column only): 0xy arpeggio, 1xx/2xx portamento up/down, 3xx tone portamento (memory), 4xy vibrato (memory), 5xy/6xy volume slide + portamento/vibrato, 7xy tremolo, 8xx pan 00–FF, 9xx offset × 256, Axy volume slide (up on x, down on y, every tick but the first), Bxx position jump, Cxx volume 00–40, Dxx pattern break to row (00–3F), E0x Amiga LED filter (E00 on, E01 off — enabling "makes the sound output more muffled"), E1x/E2x fine portamento, E3x glissando ("not widely supported"), E4x/E7x vibrato/tremolo waveform, E5x finetune (needs a note), E60/E6x pattern loop, E8x coarse pan, E9x retrigger every x ticks, EAx/EBx fine volume, ECx note cut, EDx note delay, EEx pattern delay, EFx invert loop ("permanently modifies the module file"), Fxx speed below 20h, tempo from 20h (avoid F00 and F20).
• XM = MOD plus: Gxx global volume, Hxy global volume slide, Kxx key off after xx ticks, Lxx envelope position, Pxy panning slide, Rxy multi-retrigger ("very buggy"), Txy tremor (on x+1, off y+1 ticks), X1x/X2x extra-fine portamento; hacks: EFx macro select, X5x panbrello waveform, X6x fine pattern delay, X9x, XAx high offset, Yxy panbrello, Zxx/\xx macros. Volume column (decimal): axx/bxx fine volume up/down, cxx/dxx volume slide, gxx tone portamento (16× coarser than 3xx), hxx vibrato depth, lxx/rxx pan slide, pxx pan (4-bit, rounded to multiples of 4), uxx vibrato speed only, vxx volume. Fasttracker II "was a rather buggy program", so enable the FT2 compatibility defaults.
• S3M: Axx speed, Bxx jump, Cxx break (00–3F), Dxy volume slide with DFy/DxF fine (x/y ≠ F) and D0F/DF0 every-tick when Fast Volume Slides are on, Exx/Fxx portamento with EFx/FFx fine and EEx/FEx extra fine, Gxx tone portamento, Hxy vibrato, Ixy tremor, Jxy arpeggio, Kxy/Lxy volume slide + vibrato/portamento, Oxx offset, Qxy retrigger, Rxy tremolo, S1x glissando, S2x finetune (legacy), S3x/S4x waveforms, S6x fine pattern delay, S8x pan 0–F, SB0/SBx loop, SCx cut, SDx delay, SEx pattern delay, T0x/T1x tempo slide, Txx tempo ≥ 20h, Uxy fine vibrato, Vxx global volume 00–40, Xxx pan 00–80 (XA4 surround). Not original ST3: Mxx/Nxy channel volume, Pxy pan slide, S5x, S9x, SAx, Wxy, Yxy, Zxx, volume-column pxx. Memory is mostly global: I00, J00, K00 … recall the last non-zero parameter of any command in the column; only vibrato and tone portamento have their own. OPL instruments ignore Oxx, S9x, SAx, XA4 and pan only left/centre/right.
• IT = S3M with own effect memory per command, Mxx/Nxy channel volume, Pxy pan slide, S5x, S70–S72 past-note cut/off/fade, S73–S76 NNA cut/continue/off/fade, S77–S7C volume/pan/pitch envelope off/on, S9x (only S91 original), SAx, SFx macro select, Vxx global volume 00–80, Wxy, Xxx pan 00–FF, Yxy, Zxx; SCx/SDx with 0 act as 1. Volume column: a0x/b0x fine, c0x/d0x slides, e0x/f0x portamento (4× coarser), g0x tone portamento (g01=G01, g02=G04, g03=G08, g04=G10, g05=G20, g06=G40, g07=G60, g08=G80, g09=GFF), h0x vibrato depth, pxx pan 0–64, vxx volume; all volume-column slides share one memory.
• MPTM adds S7D/S7E force pitch/filter envelope, :xy note delay + cut, #xx parameter extension (extends Bxx, Cxx, Oxx up to four rows, Txx, +xx), +xx/*xx finetune (+80 centre, ±1 semitone in sample mode), volume column o0x sample cue; o00 + Oxx makes the offset a percentage of the sample length (O80 = second half).

Practical takeaways#

Learn one column's letters per format and the memory rules: in IT "00 repeats this command", in S3M "00 repeats the last command of any kind", in MOD 300/400 recall portamento/vibrato but A00 does nothing. Random LFO waveforms and every "ModPlug hack" break playback in the original trackers.

Notable quotes#

"As Fasttracker II was a rather buggy program, many effect commands may behave in a quirky way."

Pages touched#

openmpt · effect-command-crosswalk · chord-arpeggio · pitch-slide-and-portamento · vibrato · volume-slides · retrigger · sample-offset · stereo-panning · song-init-and-looping · filter-programming · mod-format · xm-format · s3m-format · it-format · impulse-tracker · fasttracker-2 · scream-tracker-3 · protracker