<s>
OpenAL	B-Application
(	O
Open	O
Audio	O
Library	O
)	O
is	O
a	O
cross-platform	B-Operating_System
audio	O
application	B-Application
programming	I-Application
interface	I-Application
(	O
API	B-Application
)	O
.	O
</s>
<s>
It	O
is	O
designed	O
for	O
efficient	O
rendering	O
of	O
multichannel	O
three-dimensional	O
positional	B-Application
audio	I-Application
.	O
</s>
<s>
Its	O
API	B-Application
style	O
and	O
conventions	O
deliberately	O
resemble	O
those	O
of	O
OpenGL	B-Application
.	O
</s>
<s>
OpenAL	B-Application
is	O
an	O
environmental	O
3D	B-Application
audio	I-Application
library	O
,	O
which	O
can	O
add	O
realism	O
to	O
a	O
game	O
by	O
simulating	O
attenuation	O
(	O
degradation	O
of	O
sound	O
over	O
distance	O
)	O
,	O
the	O
Doppler	O
effect	O
(	O
change	O
in	O
frequency	O
as	O
a	O
result	O
of	O
motion	O
)	O
,	O
and	O
material	O
densities	O
.	O
</s>
<s>
OpenAL	B-Application
aimed	O
to	O
originally	O
be	O
an	O
open	O
standard	O
and	O
open-source	B-Application
replacement	O
for	O
proprietary	B-Application
(	O
and	O
generally	O
incompatible	O
with	O
one	O
another	O
)	O
3D	B-Application
audio	I-Application
APIs	B-Application
such	O
as	O
DirectSound	B-Device
and	O
Core	B-Operating_System
Audio	I-Operating_System
,	O
though	O
in	O
practice	O
has	O
largely	O
been	O
implemented	O
on	O
various	O
platforms	B-Device
as	O
a	O
wrapper	B-Library
around	O
said	O
proprietary	B-Application
APIs	B-Application
or	O
as	O
a	O
proprietary	B-Application
and	O
vendor-specific	O
fork	O
.	O
</s>
<s>
While	O
the	O
reference	O
implementation	O
later	O
became	O
proprietary	B-Application
,	O
there	O
are	O
open	O
source	O
implementations	O
such	O
as	O
OpenAL	B-Application
Soft	O
available	O
.	O
</s>
<s>
OpenAL	B-Application
was	O
originally	O
developed	O
in	O
2000	O
by	O
Loki	O
Software	O
to	O
help	O
them	O
in	O
their	O
business	O
of	O
porting	O
Windows	B-Application
games	O
to	O
Linux	B-Application
.	O
</s>
<s>
It	O
is	O
now	O
hosted	O
(	O
and	O
largely	O
developed	O
)	O
by	O
Creative	O
Technology	O
with	O
on-going	O
support	O
from	O
Apple	O
,	O
Blue	O
Ripple	O
Sound	O
via	O
their	O
Rapture3D	O
OpenAL	B-Application
Driver	O
,	O
and	O
individual	O
open-source	B-Application
developers	O
.	O
</s>
<s>
While	O
the	O
OpenAL	B-Application
charter	O
says	O
that	O
there	O
will	O
be	O
an	O
"	O
Architecture	O
Review	O
Board	O
"	O
(	O
ARB	O
)	O
modeled	O
on	O
the	O
OpenGL	B-Application
ARB	O
,	O
no	O
such	O
organization	O
has	O
ever	O
been	O
formed	O
and	O
the	O
OpenAL	B-Application
specification	O
is	O
generally	O
handled	O
and	O
discussed	O
via	O
email	O
on	O
its	O
public	O
mailing	O
list	O
.	O
</s>
<s>
Since	O
1.1	O
,	O
the	O
implementation	O
by	O
Creative	O
has	O
turned	O
proprietary	B-Application
,	O
with	O
the	O
last	O
releases	O
in	O
free	O
licenses	O
still	O
accessible	O
through	O
the	O
project	O
's	O
Subversion	B-Application
source	B-General_Concept
code	I-General_Concept
repository	I-General_Concept
.	O
</s>
<s>
However	O
,	O
OpenAL	B-Application
Soft	O
is	O
a	O
widely	O
used	O
open	O
source	O
alternative	O
.	O
</s>
<s>
The	O
general	O
functionality	O
of	O
OpenAL	B-Application
is	O
encoded	O
in	O
source	O
objects	O
,	O
audio	O
buffers	O
and	O
a	O
single	O
listener	O
.	O
</s>
<s>
Buffers	O
contain	O
audio	O
data	O
in	O
PCM	B-Algorithm
format	O
,	O
either	O
8	O
-	O
or	O
16-bit	B-Device
,	O
in	O
either	O
monaural	O
or	O
stereo	O
format	O
.	O
</s>
<s>
The	O
net	O
result	O
of	O
all	O
of	O
this	O
for	O
the	O
end	O
user	O
is	O
that	O
in	O
a	O
properly	O
written	O
OpenAL	B-Application
application	O
,	O
sounds	O
behave	O
quite	O
naturally	O
as	O
the	O
user	O
moves	O
through	O
the	O
three-dimensional	O
space	O
of	O
the	O
virtual	O
world	O
.	O
</s>
<s>
From	O
a	O
programmer	O
's	O
perspective	O
,	O
very	O
little	O
additional	O
work	O
is	O
required	O
to	O
make	O
this	O
happen	O
in	O
an	O
existing	O
OpenGL-based	O
3D	O
graphical	O
application	O
.	O
</s>
<s>
Unlike	O
the	O
OpenGL	B-Application
specification	O
,	O
the	O
OpenAL	B-Application
specification	O
includes	O
two	O
subsections	O
of	O
the	O
API	B-Application
:	O
the	O
core	O
consisting	O
of	O
the	O
actual	O
OpenAL	B-Application
function	O
calls	O
,	O
and	O
the	O
ALC	O
(	O
Audio	O
Library	O
Context	O
)	O
API	B-Application
which	O
is	O
used	O
to	O
manage	O
rendering	O
contexts	O
,	O
resource	O
usage	O
and	O
locking	O
in	O
a	O
cross	B-Operating_System
platform	I-Operating_System
manner	O
.	O
</s>
<s>
There	O
is	O
also	O
an	O
'	O
ALUT	O
 '	O
(	O
Audio	O
Library	O
Utility	O
Toolkit	O
)	O
library	O
that	O
provides	O
higher	O
level	O
'	O
convenience	O
 '	O
functions	O
—	O
exactly	O
analogous	O
to	O
OpenGL	B-Application
's	O
'	O
GLUT	B-Library
 '	O
.	O
</s>
<s>
In	O
order	O
to	O
provide	O
additional	O
functionality	O
in	O
the	O
future	O
,	O
OpenAL	B-Application
utilizes	O
an	O
extension	O
mechanism	O
.	O
</s>
<s>
Individual	O
vendors	O
are	O
thereby	O
able	O
to	O
include	O
their	O
own	O
extensions	O
into	O
distributions	O
of	O
OpenAL	B-Application
,	O
commonly	O
for	O
the	O
purpose	O
of	O
exposing	O
additional	O
functionality	O
on	O
their	O
proprietary	B-Application
hardware	O
.	O
</s>
<s>
ARB	O
extensions	O
have	O
the	O
prospect	O
of	O
being	O
added	O
to	O
the	O
core	O
API	B-Application
after	O
a	O
period	O
of	O
time	O
.	O
</s>
<s>
For	O
advanced	O
digital	O
signal	O
processing	O
and	O
hardware-accelerated	B-General_Concept
sound	O
effects	O
,	O
the	O
EFX	O
(	O
Effects	B-Application
Extension	I-Application
)	O
or	O
environmental	O
audio	O
extensions	O
(	O
EAX	O
)	O
can	O
be	O
used	O
.	O
</s>
<s>
The	O
single	O
listener	O
model	O
in	O
OpenAL	B-Application
is	O
tailored	O
to	O
a	O
single	O
human	O
user	O
and	O
is	O
not	O
fit	O
for	O
artificial	O
intelligence	O
or	O
robotic	O
simulations	O
or	O
multiple	O
human	O
participants	O
as	O
in	O
collaborative	O
musical	O
performances	O
.	O
</s>
<s>
OpenAL	B-Application
also	O
fails	O
to	O
take	O
into	O
account	O
sound	O
propagation	O
delays	O
(	O
the	O
speed	O
of	O
sound	O
is	O
used	O
for	O
the	O
Doppler	O
effect	O
only	O
)	O
.	O
</s>
<s>
Hence	O
OpenAL	B-Application
cannot	O
be	O
used	O
for	O
time	O
difference	O
of	O
arrival	O
calculations	O
unless	O
that	O
functionality	O
is	O
added	O
in	O
separately	O
.	O
</s>
<s>
In	O
order	O
to	O
take	O
full	B-General_Concept
speed	I-General_Concept
advantage	I-General_Concept
of	O
OpenAL	B-Application
,	O
a	O
vendor/hardware	O
specific	O
implementation	O
is	O
needed	O
and	O
these	O
are	O
seldom	O
released	O
as	O
open	O
source	O
.	O
</s>
<s>
Many	O
supported	O
platforms	B-Device
in	O
fact	O
implement	O
OpenAL	B-Application
as	O
a	O
wrapper	B-Library
which	O
simply	O
translates	O
calls	O
to	O
the	O
platform	O
's	O
native	O
,	O
and	O
often	O
proprietary	B-Application
,	O
audio	O
API	B-Application
.	O
</s>
<s>
On	O
Windows	B-Application
,	O
if	O
a	O
vendor	O
specific	O
implementation	O
is	O
not	O
detected	O
it	O
will	O
fall	O
back	O
to	O
the	O
wrap_oal.dll	O
wrapper	B-Library
library	I-Library
that	O
translates	O
OpenAL	B-Application
into	O
DirectSound	B-Device
(	O
Generic	O
Software	O
)	O
or	O
DirectSound3D	O
(	O
Generic	O
Hardware	O
)	O
;	O
the	O
removal	O
of	O
the	O
latter	O
from	O
Windows	B-Application
Vista	I-Application
onward	O
has	O
effectively	O
broken	O
generic	O
hardware	B-General_Concept
acceleration	I-General_Concept
on	O
modern	O
versions	O
of	O
Windows	B-Application
.	O
</s>
<s>
The	O
API	B-Application
is	O
available	O
on	O
the	O
following	O
platforms	B-Device
and	O
Operating	B-General_Concept
systems	I-General_Concept
:	O
Android	B-Application
(	O
supports	O
OpenSL	B-Library
ES	I-Library
)	O
,	O
AmigaOS	B-Application
3.x	O
and	O
4.x	O
,	O
Bada	B-Operating_System
,	O
BlackBerry	B-Application
10	I-Application
,	O
BlackBerry	B-Application
PlayBook	I-Application
,	O
BSD	B-Operating_System
,	O
iOS	B-Application
(	O
supports	O
Core	B-Operating_System
Audio	I-Operating_System
)	O
,	O
IRIX	B-Operating_System
,	O
Linux	B-Application
(	O
supports	O
ALSA	B-Application
,	O
OSS	B-Library
,	O
PortAudio	B-Language
and	O
PulseAudio	B-Library
)	O
,	O
Mac	B-Operating_System
OS	I-Operating_System
8	I-Operating_System
,	O
Mac	B-Operating_System
OS	I-Operating_System
9	I-Operating_System
and	O
Mac	B-Application
OS	I-Application
X	I-Application
(	O
Core	B-Operating_System
Audio	I-Operating_System
)	O
,	O
Microsoft	B-Application
Windows	I-Application
(	O
supports	O
DirectSound	B-Device
,	O
Windows	B-Application
Multimedia	O
API	B-Application
and	O
Windows	B-Application
Multimedia	O
Device	O
(	O
MMDevice	O
)	O
API	B-Application
)	O
,	O
MorphOS	B-Operating_System
,	O
OpenBSD	B-Operating_System
,	O
Solaris	B-Application
,	O
QNX	B-Operating_System
,	O
and	O
AROS	B-Application
.	O
</s>
<s>
Supported	O
gaming	O
devices	O
are	O
for	O
instance	O
:	O
GameCube	B-Application
,	O
PlayStation	B-Device
2	I-Device
,	O
PlayStation	B-Operating_System
3	I-Operating_System
,	O
Xbox	B-Operating_System
,	O
Xbox	B-Operating_System
360	I-Operating_System
,	O
Wii	B-Operating_System
,	O
and	O
PlayStation	B-Operating_System
Portable	I-Operating_System
.	O
</s>
<s>
The	O
following	O
video	O
games	O
are	O
known	O
to	O
use	O
OpenAL	B-Application
:	O
</s>
<s>
0	B-Application
A.D.	I-Application
</s>
<s>
S.T.A.L.K.E.R.	B-Application
</s>
<s>
OpenAL	B-Application
SI	O
The	O
OpenAL	B-Application
Sample	O
Implementation	O
is	O
the	O
original	O
implementation	O
,	O
from	O
Loki	O
,	O
and	O
is	O
not	O
currently	O
maintained	O
.	O
</s>
<s>
OpenAL	B-Application
Soft	O
OpenAL	B-Application
Soft	O
is	O
an	O
LGPL-licensed	O
,	O
cross-platform	B-Operating_System
,	O
software	O
implementation	O
.	O
</s>
<s>
The	O
library	O
is	O
meant	O
as	O
a	O
compatible	O
update/replacement	O
to	O
the	O
deprecated	O
OpenAL	B-Application
Sample	O
Implementation	O
,	O
as	O
well	O
as	O
a	O
free	O
alternative	O
to	O
the	O
now-proprietary	O
OpenAL	B-Application
.	O
</s>
<s>
OpenAL	B-Application
Soft	O
supports	O
mono	O
,	O
stereo	O
,	O
4-channel	O
,	O
5.1	O
,	O
6.1	O
,	O
7.1	O
,	O
HRTF	O
,	O
UHJ	O
,	O
and	O
B-Format	O
output	O
.	O
</s>
<s>
AeonWave-OpenAL	O
AeonWave-OpenAL	O
is	O
an	O
LGPL-licensed	O
OpenAL	B-Application
emulation	O
layer	O
that	O
takes	O
advantage	O
of	O
the	O
hardware	B-General_Concept
acceleration	I-General_Concept
provided	O
by	O
the	O
non-free	B-Application
but	O
low	O
cost	O
AeonWave	O
4D-audio	O
library	O
for	O
Linux	B-Application
and	O
Windows	B-Application
made	O
by	O
Adalin	O
B.V.	O
</s>
<s>
The	O
author	O
claims	O
that	O
AeonWave-OpenAL	O
implementation	O
renders	O
3D	B-Application
audio	I-Application
five	O
(	O
on	O
an	O
AMD	O
Athlon	O
64	O
X2	O
)	O
to	O
seven	O
(	O
on	O
an	O
Intel	O
Atom	O
N270	O
)	O
times	O
faster	O
than	O
either	O
OpenAL	B-Application
SI	O
or	O
OpenAL	B-Application
Soft	O
under	O
the	O
same	O
conditions	O
.	O
</s>
<s>
Rapture3D	O
OpenAL	B-Application
Driver	O
The	O
Rapture3D	O
OpenAL	B-Application
Driver	O
is	O
a	O
non-free	B-Application
,	O
commercial	O
,	O
Windows	B-Application
only	O
,	O
software	O
implementation	O
made	O
by	O
Blue	O
Ripple	O
Sound	O
.	O
</s>
