Game Engine Gems 2

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21

Data‐DrivenSoundPack

LoadingandOrganization

Simon Franco

The Creative Assembly

21.1Introduction

Typically, a game’s audio data, much like all other game data, cannot be fully

stored within the available memory of a gaming device. Therefore, we need to

develop strategies for managing the loading of our audio data. This is so we only

store in memory the audio data that is currently needed by the game. Large audio

files that are too big to fit into memory, such as a piece of music or a long sound

effect that only has one instance playing at a time, can potentially be streamed in.

Streaming a file in this way results in only the currently needed portion of the file

being loaded into memory. However, this does not solve the problem of how to

handle audio files that may require multiple instances of an audio file to be

played at the same time, such as gunfire or footsteps.

Sound effects such as these need to be fully loaded into memory. This is so

the sound engine can play multiple copies of the same sound effect, often at

slightly different times, without needing to stream the same file multiple times

and using up the limited bandwidth of the storage media.

To minimize the number of file operations performed, we typically organize

our audio files into sound packs. Each sound pack is a collection of audio files

that either need to be played together at the same time or within a short time pe-

riod of each other.

Previously, we would package up our audio files into simplified sound packs.

These would typically have been organized into a global sound pack, character

sound packs, and level sound packs. The global sound pack would contain all

audio files used by global sound events that occur across all levels of a game.