Now that a background forest day ambience audio file has been added to the project, it needs to be set to loop for it to continue playing. You have the option to loop the sound or motion FX object indefinitely, or to specify the number of times it will be looped.
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Looping properties of a Sound SFX
By default, double-clicking an object displays the object's properties. This action changes the focus of the Sound Property Editor to the object that was selected.
Looping Multiple Sound Files
While playing a single sound file with no audible loop point continues to be a relevant technique, it has become equally common practice to assemble a loop through the randomized combination of individual sound files. For example, instead of playing back a single two minute sound file, you could instead choose to randomize the playback of four 30 second files.
Moving forward with this approach for the night forest ambient background, we'll start with a single ambient sound file that has been edited into four smaller files. These files will then be imported and parented within a random container. By randomizing the order in which these four files are played back, the eventual loop composition will be created differently each time.
Start first by importing the four individual files, either using the audio file importer (as shown above) or by dragging and dropping them into the default work unit from their source folder.
Multiple sound files imported
To accommodate the complex nature of audio within a game, different types of objects can exist within the Wwise project hierarchy. You can use a combination of the following object types to group your assets and build a structure for your project.
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Sound objects
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Motion FX objects
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Actor-Mixers
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Containers
The Actor-Mixer Hierarchy includes four container types:
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Random Container: a group of one or more sounds, motion FX objects, and/or containers that are played back in a random order. |
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Sequence Container: a group of one or more sounds, motion FX objects, and/or containers that are played according to a specific playlist. |
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Switch Container: a group of one or more sounds, motion FX objects, and/or containers that are organized into a series of switches or states that correspond to the different alternatives that exist for a particular element in the game. |
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Blend Container: a group of one or more sounds, motion FX objects, and/or containers that are played back simultaneously. The sounds and containers within the blend container can be grouped into blend tracks where sound properties are mapped to game parameter values using RTPCs. Crossfades can also be applied between the sounds within a blend track based on the value of a game parameter. |
The next step in the process uses multiple audio files whose order will be randomized when played. For this example we will be creating a random container. A random container or other type of sound object can be created a few different ways:
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Using the Project Explorer toolbar
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Through the right-click contextual menu
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Using a shortcut key command (Help menu: Wwise Shortcuts Quick Reference Card)
By selecting the default work unit and then clicking the random container icon in the Project Explorer toolbar, a new random container is created within the selected work unit or sound object.
Creating a random container from the Project Explorer toolbar
Once the random container has been created and named, sound objects can be dragged and dropped directly into it.
Random container containing multiple ambient sound files
Now that the four smaller pieces of the background forest night ambience loop have been added to the container, their order of playback will be stepped through based on the properties set in the Random Container Property Editor. In Wwise, random can mean either a standard random selection, where each object within the container has an equal chance of being selected for playback, or a shuffle selection, where objects are removed from the selection pool after they have been played. You can double-click your random container to display its random properties.
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Play type properties for a random container
The same looping functionality exists within the properties of a random container, where a group of audio files can be randomized within the container and looped in the same way.
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Looping sounds in a random container using continuous play mode
Once the files have been defined as random and are continuously looping, you can also control the way that sounds transition or flow from one sound to the next. Enabling the transition property as part of the looping play mode gives you additional control over the sound.
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Adding a transition type between sound files in a loop
In this example, a sample accurate transition creates a seamless looping ambient file. Other transition options include: delay (silence), Crossfade using constant power, Crossfade using a constant amplitude, and trigger rate.
The power of this approach is in the diversity that can be gained by the recombination of multiple sound files at runtime, as opposed to using a single file of predetermined length. Additionally, by enabling control over the way that sounds transition, the diversity and complexity gained can deliver varied and non-repetitive loops. Whether you're dealing with mono, stereo, quad, or surround ambient backgrounds, each of these looping methodologies are supported.
In this section we've successfully begun the process of creating the ambient background system. With limited resources it's possible to convey a rich sense of environment using creatively designed and implemented loops as the foundation.