Wednesday, 28 October 2015

Procedural Audio Blog Post

LittleBigPlanet, GTA V, Peggle Blast & No Man’s Sky: A Study of Procedural Audio

According to Veneri et al (2008) in the Game Audio Framework, the current situation with game audio production consists of sound designers, whom have to “create and package static audio content”. Veneri et al (2008) states in the Game Audio Framework that Procedural Audio is “the algorithmical approach to the creation of audio content”. Veneri et al (2008) also suggests that the benefits of procedural audio are: “interactivity, scalability, variety, cost, storage and bandwidth”. However, they follow this by stating briefly the negative aspects of using procedural audio, such as high computational cost and unpredictable behaviour.
    A reference used in the Game Audio framework is Little Big Planet (Sony Computer Entertainment Europe, 2008), that benefits greatly from procedural audio, due the its diverse and customizable gameplay, as producing enough static wave files would take up take up too much space, where as creating a slightly varied sound effect using real-time generation, can save all the space that would be used containing wave files, while also giving a much more interactive feeling.

Farnell (2007) describes procedural audio as “sound qua process, as opposed to sound qua product”. In laymen’s terms, Farnell believes that procedural audio is sound as being a process, rather than sound as being a product. Farnell (2010) also later defined procedural audio as creating sound effects from nothing and “sound as a process rather than sound as data”. This means that rather than placing a file into a game level, as an amount of data, you would place a system inside of the game, which carries out the process of creating a sound in real-time, thus saving what game developers consider to be precious memory.
    Farnell (2010) also continues to state that there are distinct advantages to procedural audio, such as; deferred form, variety and variable cost. This means that procedural audio allows sound designers to defer decision making until run time allowing for “highly dynamic and flexible” audio, that has much more “versatility, uniqueness, dynamic level of detail and localised intelligence”, which depending on the complexity of the sound being produced can have a variably lower cost as compared to playing back any samples.
    Procedural audio can also be seen in the popular video game title Grand Theft Auto V (Rockstar, 2013) that according to Nair (2014) uses procedural audio in its vehicle sounds. This is further explained by MacGregor (2014) at GDC, who explains that the vehicle engine sounds in the game are also recorded, then cut into chunks and placed in the “granular pipeline”, which is a tool which uses information given in the game, which then uses the information to take the grains and then they can be auditioned in real-time.  He explains further that exhausts and engines will be mixed and then a granular clock is then used to sync the oscillators and match them and there is real-time DSP post-processing then thrown into the mix.

Returning to the idea of the customizable gameplay experience as mentioned in LittleBigPlanet (Sony Computer Entertainment, 2008), Schumate (2015) discussed her game Peggle Blast (EA, 2014) at this year’s Game Developers Conference. In her talk she discusses the idea of creating sounds without taking up memory.
    Schumate (2015) describes her process for doing this as making the “most of what you got!.” Her method for procedural audio for Peggle Blast (EA, 2015) was to use Wwise (Audiokinetic, 2015), in which real-time synthesis is combined with Digital Signal Processing (DSP) and creative playback behaviours and a “tiny bit of memory”.
    Schumate (2015) also demonstrates live an example of using layers of created sound, with layers of effects with layers of playback instructions, which are then generated in real-time. This simple process, demonstrates how easily a computer can generate alternative layers if the visuals change as Schumate (2015) describes that situation, that if the animations are made longer longer, then you can “change a few layers” of sound effects, meaning that suddenly you can have “something that matches the animation” rather than having to recreate the whole sound.

No Man’s Sky (Hello Games, 2016) is another game on the cutting edge of technology regarding video game audio, as it is a video game with an entirely procedurally generated universe, which in turn means that the audio content is generated procedurally as a result. Weir (2015) the audio director of the project, discusses how the audio in the game is procedurally generated as “in particular the creature noises” which are 100% synthesized using a sound generation system.
Weir (2015) in an interview with IGN, actually states that all of the creature sounds are 100% real-time. He continues to show a demonstration of the different parameters used to change the sound depending on the size or shape of the creature, which every time it plays will be slightly different due to randomized variables.
    Weir (2015) also explains that there are systems set up to affect the sounds depending on the plane or area in which they are played, as that will affect the sound, as they will all be acoustically different.


References

Farnell, A. (2007) An introduction to procedural audio and its application in computer games. [Online]. Availabel from: <http://obiwannabe.co.uk/html/papers/proc-audio/proc-audio.pdf> [Accessed 25th October 2015).

Farnell, A (2010) Designing Sound. USA: MIT Press.

Hello Games (2016) No Man’s Sky [Playstation 4] Hello Games.

MacGregor, A. (2014) The Sound of Grand Theft Auto V [Online]. Available from: <http://www.gdcvault.com/play/1020587/The-Sound-of-Grand-Theft> [Accessed 22nd October 2015].

Media Molecule (2008) LittleBigPlanet [Playstation 3] Sony Computer Entertainment.

Nair, V. (2014) What’s The Deal With Prodecural Game Audio [Online]. Available from: <http://designingsound.org/2014/10/whats-the-deal-with-procedural-game-audio/> [Accessed 25th October 2015].

PopCap (2014) Peggle Blast [iOS] Electronic Arts.

Rockstar North (2013) Grand Theft Auto V [Multiplatform] Rockstar Games.

Schumate, J,. Mattingly, RJ,. Whitmore, G. (2015) Peggle Blast: Big Concepts, Small project [Online]. Available from: <http://www.gdcvault.com/play/1022188/Peggle-Blast-Big-Concepts-Small>  [Accessed 22nd October 2015].


Veniri, O,. Gros, S,. Natkin, S,. (2008) Procedural Audio for Game using GAF [Online]. Available from: <http://cedric.cnam.fr/fichiers/RC1568.pdf> [Accessed 22nd October 2015].

Weir, P. (2015) The Otherwordly Sound of No Man’s Sky – IGN First [Online]. Available from: <https://www.youtube.com/watch?v=KUyQFRuXpfE> [Accessed 25th October 2015].


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