Dynamic music in NieR: Automata

What is Dynamic/Adaptive music?

Linear music is music that is composed and played back from start to finish without any differentiation between two separate plays, as explained by a co-founder of Polygon Treehouse Alex Kanaris-Sotiriou [4]. example of this could be a song played on the radio or a recording of an orchestra. According to Wikipedia [5], "Music that is adaptive (also called dynamic or interactive music) is background music whose volume, rhythm or tune changes in response to specific events in the game. This usually means the response or change of input from the player or their surroundings".

There are different types of ways this could be achieved in video games, for games that are more linear in its approach to gameplay such as the Devil May Cry series, the composer will know the possible limited directions that the player will take to achieve their current goal. Because of this, they can create a specific score that will trigger new upcoming events. For example, the player starts out of combat and a less upbeat ambient focused track loop can play, this could transition into a new looping section of the track when combat is initiated (potentially reverting to the first section loop if the player flees combat) and finally a finishing section loop when the player gains an A to S rank in combat and is close to eliminating the remaining enemies before returning to the first loop of music. This type of dynamic music can be described as having horizontal layering meaning it has different looping sections that change depending on the in-game scenario [6] (Also see video 1 for example, specifically changes at 3:20 that build the track into the chorus if an S rank is achieved).

Video 1 - Clip displaying the horizontal layering progression of Devil May Cry 5.

However, with non-linear games such as NieR: Automata, the composer has to build the track not knowing what the player will do or where they will go next and build the music more gradually and controlled, to combat this composer Keiichi Okabe uses a vertical layering system. The vertical system makes use of layers to build up themes up to a final point in which a track that could be considered the full final track is played. These multiple layers can be adjusted to great detail depending on the conditions the player has met, and this goes into great detail in NieR: Automata.

Dynamic music in NieR: Automata uses this concept to build its music depending on conditions the player meets during their play-through of the game, these conditions don’t only apply to simple factors such as the player being in and out of combat but also to factors such as their progression in the story or special sequences that could take place.

One of the most interesting concepts used by the game is the hacking sequences, during these sequences the character is transported to a new top-down style stage where they must destroy enemies in the stage to complete the hack and return to the main game. During this hacking sequence, the music currently playing is morphed into an 8-bit sequence and looped where the exact music theme playing just before the hack plays back in a classic 8-bit fashion. This is done using a tone filter algorithm made by the team as can be seen below [2] as well as a short clip demonstrating the effect. (figure 1 and video 2).

Figure 1 - Algorithm turning current playing track into an 8-bit version through a bespoke filter.

Conclusion

With the use of new of audio implementation systems such as Wwise and Fmod, adaptive music systems are easier to implement than ever and the game industry is very aware of this taking advantage of it in many modern games on all platforms. The tool allows players to feel more involved and in charge of their gameplay as it responds directly to their actions immersing the player in combat, storytelling and narrative experiences.

References.

https://www.youtube.com/watch?v=WLMBnoACpj8&ab_channel=JakeButineau [1]

https://www.platinumgames.com/official-blog/article/9581 [2]

Stevens R, Raybould D, 2014, Designing a game for music : Integrated design approaches for Ludic music and Interactivity. [3]

https://www.polygon-treehouse.com/blog/2018/10/24/what-the-flip-is-non-linear-music#:~:text=Linear%20music%20is%20a%20complete,make%20it%20loop%20or%20repeat [4]

PlatinumGames, NieR automata (2017) PlayStation 4, Xbox One, Microsoft Windows.

Capcom, Devil May Cry 5 (2019), PlayStation 4, PlayStation 5, Xbox One, Xbox Series X and Series S, Microsoft Windows.

https://en.wikipedia.org/wiki/Adaptive_music#:~:text=In%20video%20games%2C%20adaptive%20music,specific%20events%20in%20the%20game. [5]

https://www.oreilly.com/library/view/writing-interactive-music/9780133563528/ch08.html [6]