MDI
| Ad Lib MIDI | |||||
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| Developer: | Ad Lib, Inc. | ||||
| Header: | SMF | ||||
| Content: | Notational | ||||
| Instruments: | Internal | ||||
Target Output
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| Released: | 1989-05-08 | ||||
| First Game: | AdLib (DOS) | ||||
| Extensions |
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The MDI format was created by Ad Lib, Inc. to supersede their MUS (AdLib) format. It uses the MIDI structure but is designed to work with the OPL2 sound chip that allow it to store instrument data and change modes.
Because the format is so similar to MIDI, some MIDI players are able to play the files, but discordantly use a piano for everything (even drums) and in most cases don't release any notes. The players which can play MDI files correctly are listed below.
There don't appear to be any MDI players that support looping. This is needed to make proper recordings.
Contents
Players
- AdPlug - DOS, foobar2000, UNIX, Winamp, XMMS
- MIDI Play - DOS
- Multi Media Machine - DOS
Editors
- MIDIPLEX - Windows 32
Converters
MDI to ?
- MIDIPLEX - Windows 32 - CMF, MIDI, MUS (AdLib), SND (AdLib)
? to MDI
- MIDIPLEX - Windows 32 - CMF, MUS (AdLib), SND (AdLib)
- ROL to MIDI - DOS - ROL
Games
| Released | Title | Sample | Notes |
|---|---|---|---|
| 1990-09-20 | AdLib (DOS) | |
Note Off correct. |
| 1990-??-?? | Golden Axe (DOS) | Note Off 0. | |
| 1991-0?-?? | Atomino (DOS) | Note Off 0. | |
| 1991-??-?? | Battle Isle (DOS) | Note Off 0. | |
| 1991-??-?? | Dark Ages (DOS) | |
Note Off 0. |
| 1991-??-?? | Dragonflight (DOS) | Note Off 0. | |
| 1991-??-?? | Jumpman Lives! (DOS) | Note Off correct. | |
| 1991-??-?? | Prehistorik (DOS) | |
Note Off 0. |
| 1991-??-?? | Pro Tennis Tour 2 (DOS) | Note Off 0. | |
| 1992-0?-?? | Clik Clak (DOS) a.k.a. Gear Works (DOS) | |
Note Off correct. |
| 1992-??-?? | 3D World Tennis (DOS) | Note Off correct. | |
| 1992-??-?? | Adventure Math (DOS) | |
Note Off 0. |
| 1992-??-?? | Adventure Math Deluxe (DOS) | |
Note Off 0. |
| 1992-??-?? | Amberstar (DOS) | |
Note Off 0. |
| 1992-??-?? | Galactix (DOS) | |
Note Off correct. |
| 1992-??-?? | Starfire (DOS) | Note Off correct. | |
| 1993-??-?? | Ultimuh MCMLXVII (DOS) | Note Off correct. | |
| 1994-08-23 | Microsoft Space Simulator (DOS) | Note Off correct. | |
| 199?-??-?? | St. Thomas (DOS) | Note Off 0. |
How to Obtain
MDI files usually have to be manually extracted from game files, a process that is different for pretty much every game that uses them.
Technical
- All MDI files begin with "MThd" MIDI header and contain "MTrk" at the start of the MIDI track.
- The End Of Track "00 FF 2F 00" event is located at the end of file, but not included in the track.
- In Ad Lib's MIDI Play, all aftertouch events and the velocity parameter in Note On events equally control the specified channel's volume, though Ad Lib's ROL to MIDI does not output polyphonic aftertouch (0xA0–0xAF).
- Note Off events just release the most recent note on specified channel. The note and velocity parameters are ignored. The common version of ROL to MIDI sets the note parameter to 0 (see above).
- Control Change and Program Change events have no effect.
Sequencer-Specific Event Format
These events are used to control any OPL-compatible chip.
| Event | Length | AdLib ID | Opcode | Data |
|---|---|---|---|---|
| FF 7F | XX | 00 00 3F | XX XX | XX .. XX |
Possible Opcodes
| Opcode | Meaning | Byte # | Description |
|---|---|---|---|
| 00 01 | Patch (instrument change) | 1 | Voice / channel number for instrument |
| 2–29 | 28 byte array of parameters (see structure below) | ||
| 00 02 | Card mode | 1 | 0 = melodic, 1 = percussive |
| 00 03 | Pitch bend sensitivity (same as Registered Parameter 0) | 1 | 1–12 inclusive |
Instrument Structure
Instrument parameters are expressed with the structure, which is identical to the structure for an instrument inside a BNK file:
| Data type | Name | Description |
|---|---|---|
| MDI_OPLREGS | oplModulator | Register values for the Modulator operator (op 0) |
| MDI_OPLREGS | oplCarrier | Register values for the Carrier operator (op 1) |
| UINT8 | iModWaveSel | Modulator wave select (OPL base register 0xE0) |
| UINT8 | iCarWaveSel | Carrier wave select (OPL base register 0xE0) |
The MDI_OPLREGS structure is defined as:
| Data type | Name | Description | OPL base register |
|---|---|---|---|
| UINT8 | ksl | Key scaling level | 0x40 (bits 6-7) |
| UINT8 | multiple | Frequency multiplier | 0x20 (bits 0-3) |
| UINT8 | feedback | Feedback [op 0 only, op 1 ignored] | 0xC0 (bits 1-3) |
| UINT8 | attack | Attack rate | 0x60 (upper four bits) |
| UINT8 | sustain | Sustain level | 0x80 (upper four bits) |
| UINT8 | eg | Envelope gain (nonzero value is on) | 0x20 (bit 5) |
| UINT8 | decay | Decay rate | 0x60 (lower four bits) |
| UINT8 | releaseRate | Release rate | 0x80 (lower four bits) |
| UINT8 | totalLevel | Total output level | 0x40 (bit 0-5) |
| UINT8 | am | Amplitude modulation (Tremolo) | 0x20 (bit 7) |
| UINT8 | vib | Frequency Vibrato | 0x20 (bit 6) |
| UINT8 | ksr | Key scaling/envelope rate | 0x20 (bit 4) |
| UINT8 | con | Connector [op 0 only, op 1 ignored] | 0xC0 (bit 0, inverted) |
Channel Utilization
The channel utilization is the same as in the MUS format, except the music can be composed in both melodic and percussive modes, since the format supports mode switching during playback.
Default Timbre
Every player should load default timbre if it isn't loaded by sequencer-specific event before.
Links
- moddingwiki.shikadi.net/wiki/MDI_Format - ModdingWiki.
- cd.textfiles.com/soundsensations/MISCPROG/ZIPFILES/AD-PROG.ZIP - Source code (part of the Ad Lib Programmer's Manual).
- swag.outpostbbs.net/SOUND/0066.PAS - MDI2MUS by Colin Buckley (incomplete program source).
