Graphics are good. Graphics are shiny. But when it comes to reality-bending, emotionally-immersive, perception-shifting power, look to sound and music.

At least that’s the feeling you could get after playing Dimensions. Following their reactive music tools and Inception dream states for iOS, RjDj have turned their mind-altering sonics to gameplay. As with previous releases, these tools are powered by the open source visual development environment Pure Data. Pd engineering wizardry here meetings the compositional and sound design prowess of Hans Zimmer.

You can see a bit of how the musical world works in the teaser video above, and the music sound design video below.

But we wanted quite a lot more information. So, CDM got RjDJ’s Rob, Joe, and Martin to share some detailed thoughts on how the game experience is put together and how it works.

The App

RjDj Team: Most games require your full attention when you play them. You either live your life or play the game. Dimensions is different. It’s designed to be played in parallel with your normal life.

Gameplay is intertwined deeply into your daily life. Some dimensions unlock if you are physically active and others unlock if you are quiet. The app automatically detects what you are doing and syncs the game to it making use of every possible sensor on the iPhone.

You stay immersed in the game by listening to augmented sound and the voice of Emily from Mission Control. She guides you through many exciting challenges like collecting Artifacts and avoiding the dreaded Nephilim.

With Dimensions we are very interested in creating a gameplay experience which is between the device based focus of a casual game and the passive use of listening to music. Its a game which you play by listening – a game that place in parallel to your everyday life.

The Tech: Reading Files

We built our own version of readsf, rj_readsf, in order to be able to read compressed audio and make the samples available for processing in Pd. One advantage of readsf is that possibly lengthy audio assets do not need to be loaded into memory. If memory is limited, especially when Pd may be running in the background, limiting exposure to system memory warnings helps keep the app running and the music playing. Given that compressed audio is roughly ten times smaller in size than uncompressed audio, and that audio assets make up the majority of the size of the entire app, it is a huge benefit to be able to deliver and read compressed audio assets directly, without the need to decompress in memory or onto disk. Dimensions requires that several dozen such players be open and viable at any time, and special consideration was given to concurrent behaviour. rj_readsf can loop a file when it gets to the end, and it indicates with a bang when a file has been loaded (an asynchronous operation) or the end as been reached (in the non-looping case). rj_readsf is built on iOS standard APIs and can read any file format that iOS can.

Ed.: I’m waiting to hear if rj_readsf will be open-sourced. The issue of reading files is one we’ve had around libpd recently. While their rj_readsf sounds great, my sense is the best long-term solution will be a similar object that is independent of the APIs of any one OS, so this same set of problems may need a different solution for the open source community more generally. (Building such a tool is absolutely possible, though it might require more effort.)

The Music, and How the Music Plays with You

The music of Dimensions uses various different techniques from straight sample playback to audio analysis and synthesis:

Realtime manipulation of audio input from the mic:

This is perhaps the most recognisable technique we use. We process audio from the iPhone microphone live in many different ways. It’s kinda like a feeling of being inside the music.

The key thing we do with effects is attempting to analyse the environment of the player / listener and then making appropriate things happen within the effect. For instance, the Flux Dimension features a filterbank on the mic input. We analyse the incoming audio from the players environment and make the filter frequencies change as events occur ( either due to pitch changes or onsets ) this gives the impression that objects and activity around the player is somehow “playing” the music.

In the Ghost Dimension there is an effect which records audio whenever it detects an event, then scrubs repeatedly forwards and backwards through the sample using granular techniques stretching it out in time. This manipulation accentuates the textural and pitch based qualities of the sample as it repeats and works well with the atmospheric music Hans Zimmer composed.

Dynamically-controlled stems:

All the Dimensions use stems and hits from a conventional sequencer in some way, re-arranged live on the device relative to how the player is interacting. These stems were mainly composed in Cubase and Logic.

For example, in the Kinetic Dimension we feed accelerometer data from the device into Pd and drive the music from that. The player hears more energetic beats when they go for a run, but if they stop at the lights to cross the road, the drums immediately drop away. This was achieved with a large number of hits with all the rhythmic sequencing happening in a hybrid reactive / generative way live on the device.

In the Tranquil Dimension, the music introduces more stems the longer the player is quiet. If they make too much noise the music “shrinks away” from them and becomes quieter. If they stay in a Zen like peaceful state, the music grows into a kind of crescendo of serenity.

Reactive synthesis:

We often control parts of the music by doing a frequency analysis of incoming microphone audio from the device and then using those frequencies to determine the notes synths will play within the music. The Travelling Dream in Inception the App uses this extensively. Tranquil Dimension in Dimensions also uses onset and frequency changes to trigger synth melodies in the music.

The synths we use range in complexity from very simple additive synthesis to some great synth patches from the rjlib by Frank Barknecht and Andy Farnell.

Generative approaches:

There are some sections within Dimensions which are generative. These play back prepared samples as well as triggering onboard synthesis. They also feed the results of this through various live sampling and glitching patches. They are governed by various sets of rules which have various long term parameters, like adjusting to the intensity of the audio environment of the listener, or how dense areas of music have been around the present time.

Sample triggering:

Ghost Dimension uses a simple but effective technique of triggering samples from the music on onsets in the environment. This can cause some real jump out of your skin moments. We combined this section with a randomised very short delay on the mic which acts almost like a resonator, turning the mic sounds into creepy atonal pitched noises.

Sound Design

The main hub section in Dimensions, called the Launch screen, acts as a entry point to your augmented adventures. It also displays all available Dimensions via the floating tile icons.

Visually, these represent a snapshot of your previous experience using your location at that time. Sonically we wanted them to have an aura or energy from the Dimensions themselves.

SoundCloud examples:
Dimensions Sound Design Example by rjdjme

Example of using mixture of synthesis and samples to create user feedback when interacting with Dimension icons in the game.

Map Tile Down: several recordings of a synth in Pure Data that is played when the tiles are touched. Each one is slightly different due using two detuned oscillators.

Map Tile Open Only: a sample from Logic Pro for the woosh sound when showing the information view.

Map Tile Click: a sample from Logic Pro for touch events.

Map Tile Open: recording of how it sounds when put together.

Sound is a mixture of samples and real-time synthesis. The energy sound is made using two oscillators (one detuned) to create some modulation for a glowing effect. Added to some harmonics to make it more of a beam sound and some chorus and reverb. The open tile is made in logic, when closed it’s the same sound but reversed and pitched down in Pd.

We wanted the tiles you tap on to feel like each Dimension has some sort of energy radiating out.

Here’s a sense of how the sound design works in the game:

It’s an ambitious app, and the whole cost is US$2.99. I guarantee it’ll change your world more than a latte. (Well … unless we’re talking a really crazy latte. And that might not be legal.) As sometimes-CDM contributor Jaymis Loveday notes, there are terrific choices in coloring Google Maps, and how modes change based on ambient sound and motion.

Requires an iPhone 3GS or better, or third-generation iPod Touch or better, or an iPad.

Dimensions @ iTunes Store

More reading:
Dimensions Augments Reality Purely Through Sound [Leigh Alexander, one of my favorite game writers, for Gamasutra
The Roundabout Tapes – RjDj now plans to game reality with sound [TCTV] [Techcrunch EU]

First Augmented Reality Music CD :: Latrama :: Love & Projects :: from musikame on Vimeo.

Want the CD as object to come alive again? Here’s yet another approach: make it into an input for webcam-based augmented reality.

The album “Love & Projects” by Latrama uses the packaging to trigger augmented reality “DJing” of the playlist. Put the CD in front of your webcam, head to a browser-based tool, and you get turntable controls for playing the album live, complete with scratching, pitch, delay, filter, and volume controls. There are more downloads available, as well.

Of course, this raises the question of why you actually need the CD, given the experience is online – but then, it’s the problems with this concept that are to me interesting, themselves; working out the tension between the old (CD) and new (Web, webcam augmented reality) is where a number of opportunities lie.

The “augmented reality CDj” was developed by Madrid-based interactive shop Musikame. Musikame has been busy, re-imagining a clock face as a DJ tool and building a browser-based tool for DJing with SoundCloud tracks:

Clock DJ from musikame on Vimeo.

For SoundCloud DJing and mixing (via Sonic State, over the summer):

http://soundcloud.musikame.com/

And here’s a project that mapped Facebook faces to a wall of photos for a festival. (Take that, new Facebook profile page!)

musikame @ REC Madrid 2010 from musikame on Vimeo.

Updated: Via comments, here’s what Theo den Brinker (SoundCloud) did with that player app:

“Augmented Reality” is a fancy term for describing ways of using computer vision to overlay digital intelligence on images. In other words, you can, for instance, scratch a vinyl record using a camera – plus a tag for identifying the object’s position in 3D space.

Cambridge-based designer Todd Vanderlin put together an elegant demonstration of the possibilities here, and his video has accordingly been making the rounds. (See: Synthtopia – and I actually heard about it this morning from a high school friend. The power of the Internet.)

Todd has more details on his site, which includes all kind of wonderful projects, like laser sound fountains and, always favorite around here, creepy circuit-bent baby dolls.

AR Scratching [Todd Vanderlin]

There’s actually some work to this: you need to figure out how the album is spinning. And of course, because this is augmented reality and not reality, there’s real potential here to imagine a new kind of vinyl DJing in which normal physics don’t apply.

From the video description:

I was playing around with some AR markers the other day and came up with this idea. taking just a plain old vinyl record and attaching an AR marker to the label you can track the record in 3D space. The next question was, can you scratch the record?

So by figuring out the velocity of the records rotation and applying it to the payback of the audio you can scratch. There is some digital noise that needs to bee worked out, but sounds pretty good. Its still really hard to scratch, it takes some practice but is super fun. The next step is to figure out some nice triggers for different modes. I like the idea of not needing a turntable but the actual spinning of the record helps with the scratching and playback. I made a couple modes, one where the record is paused and you can just scratch through the song. The other looks for zero velocity for x time and then continues on with the song. If there is velocity you then are scratching and the audio is affected. I think that this project has some legs can’t wait to play more.

I Want My Augmented Reality TV

So, this has sufficiently inspired you and you want more augmented reality? We’ve got more for you.

Digital artist and magician Marco Tempest has just demonstrated what happens when you do card tricks with augmented reality – and he shares some details of his rig:

Virtual Magic: Augmented Reality Card Tricks with Marco, OpenFrameWorks [Create Digital Motion]

We’ve even seen augmented reality climbing walls.

If you’re ready to do this yourself, we have a number of resources:

CDMotion has Andy Best’s tutorial on OpenCV with Processing (not an AR-specific library, but relevant): Getting Started, Popping Bubbles

We’ve also got an in-progress library for use with mapping projections in space for “spatial augmented reality”

A New Year’s video with a library for Flash, Java

A tutorial on getting started with augmented reality using Flash

openFrameworks, a library for C++ coding (which in turn supports multitouch, augmented reality – you’ll see some projects on that page)

Bryan Chung is working on a library for Processing