Audio Systems
In order to service the need for interactive audio in Origin worlds, we use a series of audio systems that fall into two broad categories:
Audio Infrastructure: Systems that operate in the background, and provide features used by other systems. These systems are not typically directly used by anybody in an Origin world, but can be accessed as required.
Audio Tools: Systems that are used to deliver a specific type of content, and must be directly used/triggered in order to function.
Additionally, as we are working with the Unreal Engine native audio solution, it is advised to read the Unreal Engine Documentation on Working With Audio.
Audio Infrastructure
The core of our audio infrastructure is the Audio Mix Manager. This system provides an interface between users and the audio channel hierarchy, allowing for changes to the overall sound mix to be made. Additionally, an AudioMixer role exists for making changes to a mix in a live event.
The Audio Mixer
The Audio Mix Manager is a tool for managing Unreal’s SoundSubmix bus system, and provides the following general features:
Allows monitoring of current levels on audio channels.
Handles the setting of mix snapshots / presets.
Allows for live local mix changes.
Replicates mix changes from the AudioMixer role to other users.
We separate all sounds into two main categories:
World: Sounds that are diegetic - i.e. a part of the world as experienced by the characters within it (such as birds, footsteps, gameplay SFX, etc).
NonWorld: Sounds that are non-diegetic - i.e. not a part of the world (such as menu sounds, background music, etc).
Sound Classes
The Origin platform provides a set of Sound Classes that are used to route audio into the mixer system as described above. These SoundClasses are prefixed with SCL_M2.
Attenuation
The Origin platform provides a set of attenuation setting assets that can be used. Attenuation in Unreal control a number of distance-related behaviours for sounds - i.e. how a sound changes as the listener moves in relation to the source. These assets are prefixed with SAT_M2.
Data Tables
In order to simplify the process of adding and modifying audio content, we make extensive use of Data Tables. These tables can be duplicated, modified, and then assigned to the relevant Blueprints in order to modify content.
Other Infrastructure
Additional Audio Infrastructure systems are described on the following pages:
Audio Tools
Audio Tools are specific features that can be added to your project, for example, if you want to set up a playlist of music that will loop in the background, but can still be modified in a live event (e.g. skipping a track, changing the volume, etc), then you can make use of the Origin Music Controller tool.
The Audio Tools are described on the following pages:
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