Marco Tarini 1
Video Game Dev 2015/2016
Univ. Insubria
Game Audio
(notes)Marco Tarini
Game Audio
Fundamental tool of game design Impact often underestimated
for immersion for gameplay
for … “story-telling potential”
The technical aspect of it,
however, is quite simple
Sound wave
Air pressure as a function of time Waves:
frequency(Hz, audible = ~32 to ~16K), amplitude( perceived loudness)
Perception
as with most senses, response is roughly logarithmicwith physical quantity (see: decibel)
Sound wave
Air pressure as a function of time
frequency : (1/sec = 1 Hz)
Marco Tarini 3
Sound wave
Air pressure as a function of time To digitalize it:
sampleit
at some fixed rate quantizesamples
at some fixed precision
…then probably compressit wavelet compression works great mp3 compression: perceptual encoding
Assets for generic sounds:
most common file formats
.mp3
perceptual encoding good balance
most common
.ogg (vorbis)
optimized for music usually best quality
.wav
often (but not necessarily) uncompressed
Specialized assets for music
Store the score instead?
e.g. MIDI specifications
much cheaper than sampled sound to store, but requires instrument liberary at runtime not much used anymore (in games) still most convenient for proceduralmusic?
Specialized assets for ambient sounds
Randomized blend of individual waves
according to customizable rules e.g. randomized repetitions, at randomized times
Authoring: specialized game tools
e.g. see http://rpg.ambient-mixer.com/
Marco Tarini 5
Sound Rendering:
basic playback tasks
Mixing
Tweak / Tune: (useful to randomize!) loudness
both frequencyand speed
only frequency, only speed (less trivial)
other dynamic effects:
reverb echos…
“3D” sound “rendering”
localize sounds in 3D (using stereo) tune loudness
abstractions:
Libs: OpenAL, Wwise…
(and, many audio modules of
game engines)
the listener the sources
the buffers(the assets to be played / mixed) (sitting in nodes of the scene graph)
Sound Rendering:
advanced tasks
Sound occlusions
how to: reuse collision objects!
triggering effects like:
muffling absorption
Full fledged procedural sound synthesis
e.g. procedural sounds for collisions from physical material specification not (yet?) used
active (niche) research topic
Triggering sounds in the game
from scripts
e.g. at collision response
e.g. accompanying all sorts of game logic from “doors opening” to “level completed”
as «Actions» of the AI
see: AIfor NPCs
automatically tied to animations
e.g.
footsteps during walk / run
detach from ground / land sounds for jumps air-swishes during sword swings
…
convenient for easy synchronization action / sound
Authoring sound assets
Synthesized / simulated / procedural fxs : baked
(rare) Captured fxs :
hardware: a good microphone!
by: “Foley artists”
very often: just bought / downloaded from repositories Voice :
hardware: a good microphone!
by voice actors
(sometimes, during motion capture sections)
speech synthesis? won’t be used (for some time yet) Composed (for music) :
musicians: frequent 3rd members of 3-man dev teams recent improvements of tools (both HW and SW)
then, sound editing
