Heard About: Mirror’s Edge Catalyst

For the respected DICE audio team, a second instalment of Mirror’s Edge offered the chance and challenge to create yet more potentially award-winning sound. So what were their key targets for an audio upgrade?

We felt we could do a lot more; more memory, surface types, music, ambiences, more everything. Not for the sake of it, but to add aural diversity to the experience of exploring the city; different music, ambiences and spot sounds for different districts. For example, air con units rattle in rundown areas, whereas they’d hum in tune with the music in high-end areas.

We’ve also added more surface types to colour the player’s journey through the world. We really wanted to bring the city to life while they free-roam; monorails and drones whizz above their head, trains and cars roar below and adverts echo between the two.

Some things we kept the same: the triumphant return of Solar Fields, for example. His music is part of the soul of Mirror’s Edge.

"A raycast and indoor/outdoor ambience/filtering system enabled us to, on-the-fly and independent of geometry changes in the city, create a realistic reverb/reflection model."

James Slavin, EA DICE

Tell as about the creative process and team roles, and how you managed to avoid ‘crunch’.

Individual ownership and creativity were vital. First, we created a sound design ‘bible’, setting out how, where and why things should play. Once we all knew what we wanted to do, we ran with it.

Playing on each other’s natural strengths, we divided responsibilities into SFX, tech, music and speech. We swapped hats when necessary; having that ownership really helped everyone focus.

Early on, Olof Strömqvist worked on a raycast and indoor/outdoor ambience/filtering system. It went through a few iterations, but enabled us to, on-the-fly and independent of geometry changes in the city, create a realistic reverb/reflection model. We sonically anchored the futuristic world by having locations behave as you’d expect in the real world.

Magnus Walterstad simultaneously worked on music design, re-arranging the original Mirror’s Edge tracks at first, to test behaviors with a familiar palate.

Patrick Michalak worked on speech design for Faith and the AI, while I worked on the material selection for footsteps, combat impacts and UI design. Because we did a lot of this heavy lifting early on, we were able to react to changes and eventually mix the game three times.

How did you give life to Faith and her environment using audio? 

We did a few things with breathing, foley, emotes and footsteps.

Faith’s lungs are her ‘engines’, so we kept the breathing rhythmic until she got damaged in combat. Then her punch and impact emotes transformed into coughs and splutters – plus, we added panic breathing as she fell to her death. We told the story of the world from the feet up.

Each surface type you encounter describes a little of where you are; squeaky polished glass and clean marble contrast greatly with corrugated metal and dirty concrete. One speaks of a high-end environment, the other is indicative of a rundown area. They also serve a more intimate purpose, as it’s these things that give Faith her friction, physicality and weight as she runs, scrapes, slides, jumps, lands and rolls through the world.

What about music implementation and function?

Where you have to race – time trials and runners’ routes – we used distance-over-time as a parameter to build the music. For example, the longer you run unimpeded and keep your ‘flow’, the more the rhythmic elements of the track are introduced. Thus, you enjoy running.

If you miss a jump and end up hanging off a building, you lose your speed and the music responds by slowly removing the same beats that drove you forward – like a soft penalty.

You can get the beats back by picking yourself up and carrying on. It responds to your speed so should never play exactly the same twice.

All this week, Develop is taking a deeper look into sound and music in video games through our Audio Special.