Spatial Sound for Computer Games and Virtual Reality - Game Sound Technology and Player Interaction: Concepts and Developments - page 308

Figure 12. Basic MMAPI process. The Manager class bridges between the DataSource class and Player
interface. Primitive controls are implemented via the Player's methods

The SoundSource3D module performs control
effects specifically relating to positioning sources
in the virtual space. These include sound source
directivity (sound cones), distance attenuation,
Doppler shift, location control, specifying the
dimensions of an extended sound source (not a
point source), obstruction of the sound traveling
from source to listener, and reverberation effects
(JSR-234 Group, 2005; Paavola & Page, 2005).
The Spectator class represents the listener
in the virtual space (JSR-234 Group, 2005). As
with other sound sources in the virtual space, the
listener/spectator must also possess spatial cues.
The controls associated with the Spectator class
are location, Doppler, and orientation.

phones, PDAs and mobile digital music players.
It is a C-language audio API with some overlap
with OpenMAX AL 1.0, a multimedia/record-
ing API for embedded systems from the same
group. Like the relationship between MMAPI
and AMMS, OpenMAX AL has basic audio ca-
pabilities, with OpenSL ES providing advanced
3D audio and sonic effects, and both share many
common methods. However, unlike MMAPI and
AMMS, both OpenMAX AL and OpenSL ES are
entirely independent and each can perform as a
standalone API on target devices.
Three Profiles are present in the OpenSL
ES implementation: Phone , Music , and Game
(see Table 5). Different audio capabilities exist
for different profiles but manufacturers are free
to implement two or all three profiles on their
devices. All features of a given profile have to
be implemented by the manufacturer in order to
ensure compatibility. Therefore, a manufacturer
implementing the Phone profile, but wanting to

OpensL Es

OpenSL ES is an open standard API for interactive
spatial audio for embedded systems developed
by the Khronos Group (2009). Target devices
for OpenSL ES are basic mobile phones, smart