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iMUSE

Let the music wait for the right moment

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Michael Land and Peter McConnell’s iMUSE joins game events to authored musical transitions. It lets a score respond to the player while preserving musical timing.

iMUSE is LucasArts’ interactive music system, created by Michael Land and Peter McConnell. It connects what happens in a game to the timing and structure of its score. Music can respond to a player entering a room without abandoning the phrase already under way.

The system is closely associated with Monkey Island 2, part of the Monkey Island series. It helps an adventure’s soundtrack follow a player who can pause, explore or leave at an unpredictable moment.

A game event requests a change during a musical phrase. The score reaches an authored decision point, then takes a prepared transition into the next section.
Original schematic of an authored musical transition. The game requests the change; the score provides suitable places and routes for making it.

A request and a musical answer

Land and McConnell’s patent describes prepared decision points, markers and commands. The composer supplies material and ways to move through it. The game selects what should happen, and the music system carries out that request at a suitable point.

That separation solves a practical problem. A story event happens on the player’s schedule, while a tune has its own rhythm. Cutting immediately to a different piece may sound abrupt. Waiting for an authored transition can acknowledge the event and still make musical sense.

Several kinds of machinery

The original MIDI approach works with musical performance information: notes, instruments and timing. Later digital iMUSE systems work with recorded audio. ScummVM preserves separate implementations of these systems, making their different responsibilities visible.

They share a goal, but the machinery differs. Rearranging a sequence of note events and moving between streams of recorded sound present different problems of timing and continuity.

SCUMM supplies the surrounding adventure logic, while INSANE addresses another part of LucasArts’ presentation: keeping interactive animation moving. Together they show why game engines often grew as cooperating systems, each handling a particular kind of time.

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