MDI

[[Category: Formats With {{{Header}}} Headers]] [[Category: Formats With {{{Content}}} Content]] [[Category: Formats With {{{Instruments}}} Instruments]]

Ad Lib MIDI
Developer:	Ad Lib, Inc.
Header:	{{{Header}}}
Content:	{{{Content}}}
Instruments:	{{{Instruments}}}
Target Output
Released:	1989-05-08
First Game:	?
Extensions	*.mdi

The MDI format was created by Ad Lib, Inc. to upgrade from ROL format. It uses the MIDI structure but incorporates OPL2 commands that allow it to store instrument data and change modes, similar to how CMF works. Because the format is so similar to MIDI, some MIDI players are able to play the files, though they won't utilize the instrument data or set the song into the correct mode, so the song won't sound correct. The players which can play MDI files correctly are listed below.

Players

(Category)

• MIDI Play - DOS
• Multi Media Machine - DOS

Converters

(Category)

• ROL to MIDI - DOS - ROL

Games

Released	Title	Sample
1990-??-??	Golden Axe (DOS)
1991-??-??	Dark Ages (DOS)
1991-??-??	Prehistorik (DOS)
1992-??-??	Amberstar (DOS)
1992-??-??	Gear Works (DOS)
1992-??-??	Starfire (DOS)
1993-??-??	Ultimuh MCMLXVII (DOS)

Games That Use MDI

Technical

• All MDI files begin with "MThd" MIDI header and contain "MTrk" at the start of the MIDI track.
• The End Of Track "FF 2F 00" event is located at the end of file, but not included in the track.
• Some Note Off events may have only Velocity parameter to trigger the note off.
• Program Change events are not used in the track.

Sequencer-specific event format

These events are used to control OPL-compatible chip.

Delta-ticks	Event	Length	Ad Lib ID	Opcode	Data
00	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 BNK format)
00 02	Card mode	1	0 = melodic, 1 = percussive
00 03	Pitch bend sensitivity	1	1 - 12 inclusive

Channels utilization

Hex channel	MIDI channel	Use in melodic mode	Use in percussive mode
0x00	1	Normal instrument	Normal instrument
0x01	2	Normal instrument	Normal instrument
0x02	3	Normal instrument	Normal instrument
0x03	4	Normal instrument	Normal instrument
0x04	5	Normal instrument	Normal instrument
0x05	6	Normal instrument	Normal instrument
0x06	7	Normal instrument	Bass drum
0x07	8	Normal instrument	Snare drum
0x08	9	Normal instrument	Tom tom
0x09	10	Normal instrument	Top cymbal
0x0A	11	Normal instrument	Hi-hat cymbal
0x0B	12	Unused	Unused
0x0C	13	Unused	Unused
0x0D	14	Unused	Unused
0x0E	15	Unused	Unused
0x0F	16	Unused	Unused

Links

• cd.textfiles.com/soundsensations/MISCPROG/AD-PROG/ - Ad Lib software and sources.
• cd.textfiles.com/soundsensations/MISCPROG/AD-PROG/MIDIPLAY.BAS - The Ad Lib sequencer-specific event basic explanation.
• swag.outpostbbs.net/SOUND/0066.PAS - MDI2MUS by Colin Buckley (incomplete program source)