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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340341342343344345346347348349350351352353354355356357358359360361362363364365taken from: https://github.com/schismtracker/schismtracker/wiki/ITTECH.TXTHeader Layout: 0 1 2 3 4 5 6 7 8 9 A B C D E F ┌───┬───┬───┬───┬───────────────────────────────────────────────┐0000: │'I'│'M'│'P'│'M'│ Song Name, max 26 characters, includes NULL │ ├───┴───┴───┴───┴───────────────────────────────────────┬───────┤0010: │.......................................................│PHiligt│ ├───────┬───────┬───────┬───────┬───────┬───────┬───────┼───────┤0020: │OrdNum │InsNum │SmpNum │PatNum │ Cwt/v │ Cmwt │ Flags │Special│ ├───┬───┼───┬───┼───┬───┼───────┼───────┴───────┼───────┴───────┤0030: │GV │MV │IS │IT │Sep│PWD│MsgLgth│Message Offset │ Reserved │ ├───┴───┴───┴───┴───┴───┴───────┴───────────────┴───────────────┤0040: │ Chnl Pan (64 bytes)...........................................│ ├───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┤ ├───┴───┴───┴───┴───┴───┴───┴───┴───┴───┴───┴───┴───┴───┴───┴───┤0080: │ Chnl Vol (64 bytes)...........................................│ ├───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┤ ├───┴───┴───┴───┴───┴───┴───┴───┴───┴───┴───┴───┴───┴───┴───┴───┤00C0: │ Orders, Length = OrdNum │ ├───────────────────────────────────────────────────────────────┤xxxx: │ 'Long' Offset of instruments, Length = InsNum*4 (1) │ ├───────────────────────────────────────────────────────────────┤xxxx: │ 'Long' Offset of samples headers, Length = SmpNum*4 (2) │ ├───────────────────────────────────────────────────────────────┤xxxx: │ 'Long' Offset of patterns, Length = PatNum*4 (3) │ └───────────────────────────────────────────────────────────────┘ (1) Offset = 00C0h+OrdNum (2) Offset = 00C0h+OrdNum+InsNum*4 (3) Offset = 00C0h+OrdNum+InsNum*4+SmpNum*4 Note that if the (long) offset to a pattern = 0, then the pattern is assumed to be a 64 row empty pattern. PHiliht = Pattern row hilight information. Only relevant for pattern editing situations. Cwt: Created with tracker. Impulse Tracker y.xx = 0yxxh Cmwt: Compatible with tracker with version greater than value. (ie. format version) OrdNum: Number of orders in song. InsNum: Number of instruments in song SmpNum: Number of samples in song PatNum: Number of patterns in song Flags: Bit 0: On = Stereo, Off = Mono Bit 1: Vol0MixOptimizations - If on, no mixing occurs if the volume at mixing time is 0 (redundant v1.04+) Bit 2: On = Use instruments, Off = Use samples. Bit 3: On = Linear slides, Off = Amiga slides. Bit 4: On = Old Effects, Off = IT Effects Differences: - Vibrato is updated EVERY frame in IT mode, whereas it is updated every non-row frame in other formats. Also, it is two times deeper with Old Effects ON - Command Oxx will set the sample offset to the END of a sample instead of ignoring the command under old effects mode. - (More to come, probably) Bit 5: On = Link Effect G's memory with Effect E/F. Also Gxx with an instrument present will cause the envelopes to be retriggered. If you change a sample on a row with Gxx, it'll adjust the frequency of the current note according to: NewFrequency = OldFrequency * NewC5 / OldC5; Bit 6: Use MIDI pitch controller, Pitch depth given by PWD Bit 7: Request embedded MIDI configuration (Coded this way to permit cross-version saving) Special: Bit 0: On = song message attached. Song message: Stored at offset given by "Message Offset" field. Length = MsgLgth. NewLine = 0Dh (13 dec) EndOfMsg = 0 Note: v1.04+ of IT may have song messages of up to 8000 bytes included. Bit 1: Reserved Bit 2: Reserved Bit 3: MIDI configuration embedded Bit 4-15: Reserved GV: Global volume. (0->128) All volumes are adjusted by this MV: Mix volume (0->128) During mixing, this value controls the magnitude of the wave being mixed. IS: Initial Speed of song. IT: Initial Tempo of song Sep: Panning separation between channels (0->128, 128 is max sep.) PWD: Pitch wheel depth for MIDI controllers Chnl Vol: Volume for each channel. Ranges from 0->64 Chnl Pan: Each byte contains a panning value for a channel. Ranges from 0 (absolute left) to 64 (absolute right). 32 = central pan, 100 = Surround sound. +128 = disabled channel (notes will not be played, but note that effects in muted channels are still processed) Orders: This is the order in which the patterns are played. Valid values are from 0->199. 255 = "---", End of song marker 254 = "+++", Skip to next orderInstrument Format: 0 1 2 3 4 5 6 7 8 9 A B C D E F ┌───┬───┬───┬───┬───────────────────────────────────────────────┐0000: │'I'│'M'│'P'│'I'│ DOS FileName (12345678.123) │ ├───┼───┼───┼───┼───────┬───┬───┬───┬───┬───┬───┬───────┬───┬───┤0010: │00h│NNA│DCT│DCA│FadeOut│PPS│PPC│GbV│DfP│RV │RP │TrkVers│NoS│ x │ ├───┴───┴───┴───┴───────┴───┴───┴───┴───┴───┴───┴───────┴───┴───┤0020: │ Instrument Name, max 26 bytes, includes NUL...................│ ├───────────────────────────────────────┬───┬───┬───┬───┬───────┤0030: │.......................................│IFC│IFR│MCh│MPr│MIDIBnk│ ├───────────────────────────────────────┴───┴───┴───┴───┴───────┤0040: │ Note-Sample/Keyboard Table, Length = 240 bytes................│ ├───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┤ ├───┴───┴───┴───┴───┴───┴───┴───┴───┴───┴───┴───┴───┴───┴───┴───┤0130: │ Envelopes.....................................................│ ├───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┬───┤ IFC = Initial Filter cutoff IFR = Initial Filter resonance NNA = New Note Action 0 = Cut 1 = Continue 2 = Note off 3 = Note fade DCT = Duplicate Check Type 0 = Off 1 = Note 2 = Sample 3 = Instrument DCA: Duplicate Check Action 0 = Cut 1 = Note Off 2 = Note fade FadeOut: Ranges between 0 and 128, but the fadeout "Count" is 1024 See the Last section on how this works. Fade applied when: 1) Note fade NNA is selected and triggered (by another note) 2) Note off NNA is selected with no volume envelope or volume envelope loop 3) Volume envelope end is reached PPS: Pitch-Pan separation, range -32 -> +32 PPC: Pitch-Pan center: C-0 to B-9 represented as 0->119 inclusive GbV: Global Volume, 0->128 DfP: Default Pan, 0->64, &128 => Don't use RV: Random volume variation (percentage) RP: Random panning variation (panning change - not implemented yet) MCh = MIDI Channel MPr = MIDI Program (Instrument) TrkVers: Tracker version used to save the instrument. This is only used in the instrument files. NoS: Number of samples associated with instrument. This is only used in the instrument files. Note-Sample/Keyboard Table. Each note of the instrument is first converted to a sample number and a note (C-0 -> B-9). These are stored as note/sample byte pairs (note first, range 0->119 for C-0 to B-9, sample ranges from 1-99, 0=no sample)Envelope Layout: Envelopes: 3 structures, first for volume (130h), second for panning (182h), third for pitch (1D4h). Each is structured as such: 0 1 2 3 4 5 6....... ┌───┬───┬───┬───┬───┬───┬───────────────────────────────────┬───┐xxxx: │Flg│Num│LpB│LpE│SLB│SLE│ Node points, 25 sets, 75 bytes....│ x │ ├───┼───┼───┼───┼───┼───┼───┬───┬───┬───┬───┬───┬───┬───┬───┼───┤ Flg: Bit 0: Envelope on/off, 1 = on, 0 = off Bit 1: Loop on/off, 1 = on, 0 = off Bit 2: SusLoop on/off, 1 = on, 0 = off For Pitch envelope only: Bit 7: Use pitch envelope as filter envelope instead. Num = Number of node points LpB = Loop beginning SLB = Sustain loop beginning LpE = Loop end SLE = Sustain loop end Node point = 1 byte for y-value (0->64 for vol, -32->+32 for panning or pitch) 1 word (2 bytes) for tick number (0->9999) Total length of an instrument is 547 bytes, but 554 bytes are written, just to simplify the loading of the old format. (Hence there are 7 'wasted' bytes per instrument)Sample Header Layout: 0 1 2 3 4 5 6 7 8 9 A B C D E F ┌───┬───┬───┬───┬───────────────────────────────────────────────┐0000: │'I'│'M'│'P'│'S'│ DOS Filename (12345678.123) │ ├───┼───┼───┼───┼───────────────────────────────────────────────┤0010: │00h│GvL│Flg│Vol│ Sample Name, max 26 bytes, includes NUL.......│ ├───┴───┴───┴───┴───────────────────────────────────────┬───┬───┤0020: │.......................................................│Cvt│DfP│ ├───────────────┬───────────────┬───────────────┬───────┴───┴───┤0030: │ Length │ Loop Begin │ Loop End │ C5Speed │ ├───────────────┼───────────────┼───────────────┼───┬───┬───┬───┤0040: │ SusLoop Begin │ SusLoop End │ SamplePointer │ViS│ViD│ViR│ViT│ └───────────────┴───────────────┴───────────────┴───┴───┴───┴───┘The cache file has the following pieces of information added on: 0 1 2 3 4 5 6 7 8 9 A B C D E F ┌───────────────┬───────┬───────┬───┬───────────────────────────┐0050: │ File Size │ Date │ Time │Fmt│...........................│ └───────────────┴───────┴───────┴───┴───────────────────────────┘ Fmt. 0 = unchecked. 1 = directory, 2 = it sample, 3 = st sample GvL: Global volume for instrument, ranges from 0->64 Flg: Bit 0. On = sample associated with header. Bit 1. On = 16 bit, Off = 8 bit. Bit 2. On = stereo, Off = mono. Stereo samples not supported yet Bit 3. On = compressed samples. Bit 4. On = Use loop Bit 5. On = Use sustain loop Bit 6. On = Ping Pong loop, Off = Forwards loop Bit 7. On = Ping Pong Sustain loop, Off = Forwards Sustain loop Vol: Default volume for instrument Length: Length of sample in no. of samples NOT no. of bytes LoopBeg: Start of loop (no of samples in, not bytes) Loop End: Sample no. AFTER end of loop C5Speed: Number of bytes a second for C-5 (ranges from 0->9999999) SusLBeg: Start of sustain loop SusLEnd: Sample no. AFTER end of sustain loop SmpPoint: 'Long' Offset of sample in file. ViS: Vibrato Speed, ranges from 0->64 ViD: Vibrato Depth, ranges from 0->64 ViT: Vibrato waveform type. 0=Sine wave 1=Ramp down 2=Square wave 3=Random (speed is irrelevant) ViR: Vibrato Rate, rate at which vibrato is applied (0->64) The depth of the vibrato at any point is worked out in the following way: Every processing cycle, the following occurs: 1) Mov AX, [SomeVariableNameRelatingToVibrato] 2) Add AL, Rate 3) AdC AH, 0 4) AH contains the depth of the vibrato as a fine-linear slide. 5) Mov [SomeVariableNameRelatingToVibrato], AX ; For the next ; cycle. For those that don't understand assembly, then the depth is basically the running-sum of the rate divided by 256. Sample vibrato uses a table 256-bytes long Convert - bits other than bit 0 are used internally for the loading of alternative formats. Bit 0: Off: Samples are unsigned } IT 2.01 and below use unsigned samples On: Samples are signed } IT 2.02 and above use signed samples Bit 1: Off: Intel lo-hi byte order for 16-bit samples } Safe to ignore On: Motorola hi-lo byte order for 16-bit samples } these values... Bit 2: } Off: Samples are stored as PCM values } On: Samples are stored as Delta values } Bit 3: } On: Samples are stored as byte delta values } (for PTM loader) } Bit 4: } On: Samples are stored as TX-Wave 12-bit values } Bit 5: } On: Left/Right/All Stereo prompt } Bit 6: Reserved Bit 7: Reserved DfP - Default Pan. Bits 0->6 = Pan value, Bit 7 ON to USE (opposite of inst)Pattern Layout: 0 1 2 3 4 5 6 7 8 9 A B C D E F ┌───────┬───────┬───┬───┬───┬───┬───────────────────────────────┐0000: │Length │ Rows │ x │ x │ x │ x │ Packed data................ │ ├───┬───┼───┬───┼───┼───┼───┼───┼───┬───┬───┬───┬───┬───┬───┬───┤ Length: Length of packed pattern, not including the 8 byte header Note that the pattern + the 8 byte header will ALWAYS be less than 64k Rows: Number of rows in this pattern (Ranges from 32->200) Patterns are unpacked by the following pseudocode... (this may look horrible, but in practise, it's just as convenient as the S3M pattern format for playback (but not for display)) GetNextChannelMarker: Read byte into channelvariable. if(channelvariable = 0) then end of row Channel = (channelvariable-1) & 63 ; Channel is 0 based. if(channelvariable & 128) then read byte into maskvariable else maskvariable = previousmaskvariable for current channel if(maskvariable & 1), then read note. (byte value) // Note ranges from 0->119 (C-0 -> B-9) // 255 = note off, 254 = notecut // Others = note fade (already programmed into IT's player // but not available in the editor) if(maskvariable & 2), then read instrument (byte value) // Instrument ranges from 1->99 if(maskvariable & 4), then read volume/panning (byte value) // Volume ranges from 0->64 // Panning ranges from 0->64, mapped onto 128->192 // Prepare for the following also: // 65->74 = Fine volume up // 75->84 = Fine volume down // 85->94 = Volume slide up // 95->104 = Volume slide down // 105->114 = Pitch Slide down // 115->124 = Pitch Slide up // 193->202 = Portamento to // 203->212 = Vibrato Effects 65 is equivalent to D0F, 66 is equivalent to D1F -> 74 = D9F Similarly for 75-84 (DFx), 85-94 (Dx0), 95->104 (D0x). (Fine) Volume up/down all share the same memory (NOT shared with Dxx in the effect column tho). Pitch slide up/down affect E/F/(G)'s memory - a Pitch slide up/down of x is equivalent to a normal slide by x*4 Portamento to (Gx) affects the memory for Gxx and has the equivalent slide given by this table: SlideTable DB 1, 4, 8, 16, 32, 64, 96, 128, 255 Vibrato uses the same 'memory' as Hxx/Uxx. if(maskvariable & 8), then read command (byte value) and commandvalue // Valid ranges from 0->31 (0=no effect, 1=A, 2=B, 3=C, etc.) if(maskvariable & 16), then note = lastnote for channel if(maskvariable & 32), then instrument = lastinstrument for channel if(maskvariable & 64), then volume/pan = lastvolume/pan for channel if(maskvariable & 128), then { command = lastcommand for channel and commandvalue = lastcommandvalue for channel } Goto GetNextChannelMarker