<s>
DirectSound	B-Device
is	O
a	O
deprecated	O
software	O
component	O
of	O
the	O
Microsoft	B-Application
DirectX	I-Application
library	O
for	O
the	O
Windows	B-Application
operating	I-Application
system	I-Application
,	O
superseded	O
by	O
XAudio2	B-Device
.	O
</s>
<s>
It	O
provides	O
a	O
low-latency	O
interface	O
to	O
sound	B-Device
card	I-Device
drivers	O
written	O
for	O
Windows	B-Application
95	O
through	O
Windows	B-Application
XP	O
and	O
can	O
handle	O
the	O
mixing	O
and	O
recording	O
of	O
multiple	O
audio	O
streams	O
.	O
</s>
<s>
DirectSound	B-Device
was	O
originally	O
written	O
for	O
Microsoft	O
by	O
John	B-Library
Miles	I-Library
.	O
</s>
<s>
Besides	O
providing	O
the	O
essential	O
service	O
of	O
passing	O
audio	O
data	O
to	O
the	O
sound	B-Device
card	I-Device
,	O
DirectSound	B-Device
provides	O
other	O
essential	O
capabilities	O
such	O
as	O
recording	O
and	O
mixing	O
sound	O
,	O
adding	O
effects	O
to	O
sound	O
(	O
e.g.	O
,	O
reverb	O
,	O
echo	O
,	O
or	O
flange	O
)	O
,	O
using	O
hardware	B-General_Concept
accelerated	I-General_Concept
buffers	O
in	O
Windows	B-Application
95	O
through	O
XP	O
,	O
and	O
positioning	B-Application
sounds	I-Application
in	I-Application
3D	I-Application
space	I-Application
.	O
</s>
<s>
DirectSound	B-Device
also	O
provides	O
a	O
means	O
to	O
capture	O
sounds	O
from	O
a	O
microphone	O
or	O
other	O
input	O
and	O
controlling	O
capture	O
effects	O
during	O
audio	O
capture	O
.	O
</s>
<s>
After	O
many	O
years	O
of	O
development	O
,	O
today	O
DirectSound	B-Device
is	O
a	O
mature	O
API	B-Application
,	O
and	O
supplies	O
many	O
other	O
useful	O
capabilities	O
,	O
such	O
as	O
the	O
ability	O
to	O
play	O
multichannel	O
sounds	O
at	O
high	O
resolution	O
.	O
</s>
<s>
While	O
DirectSound	B-Device
was	O
designed	O
to	O
be	O
used	O
by	O
games	O
,	O
today	O
it	O
is	O
used	O
to	O
play	O
audio	O
in	O
many	O
audio	O
applications	B-Application
.	O
</s>
<s>
DirectShow	B-Library
uses	O
DirectSound	B-Device
's	O
hardware	O
audio	O
acceleration	O
capabilities	O
if	O
the	O
sound	B-Device
card	I-Device
's	O
hardware	O
audio	O
acceleration	O
capabilities	O
exist	O
and	O
are	O
exposed	O
by	O
the	O
audio	O
driver	O
.	O
</s>
<s>
DirectSound	B-Device
is	O
a	O
user	B-Operating_System
mode	I-Operating_System
API	B-Application
that	O
provides	O
an	O
interface	O
between	O
applications	B-Application
and	O
the	O
sound	B-Device
card	I-Device
driver	O
,	O
enabling	O
applications	B-Application
to	O
produce	O
sounds	O
and	O
play	O
back	O
music	O
.	O
</s>
<s>
DirectSound	B-Device
was	O
considered	O
revolutionary	O
when	O
it	O
was	O
introduced	O
in	O
1995	O
,	O
as	O
it	O
featured	O
multiple	O
simultaneous	O
audio	O
streams	O
and	O
allowed	O
several	O
applications	B-Application
to	O
access	O
the	O
sound	B-Device
card	I-Device
simultaneously	O
.	O
</s>
<s>
DirectSound	B-Device
provides	O
sample	O
rate	O
conversion	O
and	O
sound	O
mixing	O
(	O
volume	B-Algorithm
and	O
pan	O
)	O
for	O
an	O
unlimited	O
number	O
of	O
audio	O
sources	O
;	O
however	O
,	O
the	O
practical	O
limits	O
are	O
the	O
number	O
of	O
hardware	O
audio	O
sources	O
and	O
the	O
performance	O
of	O
software	O
mixers	O
.	O
</s>
<s>
The	O
DirectSound	B-Device
architecture	O
features	O
a	O
concept	O
of	O
the	O
"	O
ring	O
buffer	O
"	O
which	O
would	O
be	O
continuously	O
played	O
in	O
a	O
cycle	O
.	O
</s>
<s>
On	O
supported	O
sound	B-Device
cards	I-Device
,	O
DirectSound	B-Device
would	O
try	O
to	O
use	O
"	O
hardware	B-General_Concept
accelerated	I-General_Concept
"	O
buffers	O
,	O
i.e.	O
</s>
<s>
the	O
ones	O
which	O
either	O
can	O
be	O
placed	O
in	O
local	O
sound	B-Device
card	I-Device
memory	O
,	O
or	O
can	O
be	O
accessed	O
by	O
the	O
sound	B-Device
card	I-Device
from	O
the	O
system	O
memory	O
.	O
</s>
<s>
If	O
hardware	B-General_Concept
acceleration	I-General_Concept
is	O
not	O
available	O
,	O
DirectSound	B-Device
would	O
create	O
audio	O
buffers	O
in	O
the	O
system	O
memory	O
and	O
use	O
purely	O
software	O
mixing	O
.	O
</s>
<s>
Some	O
late	O
DOS-era	O
"	O
wavetable	O
"	O
sound	B-Device
cards	I-Device
such	O
as	O
Sound	B-Device
Blaster	I-Device
AWE32	I-Device
and	O
Gravis	B-Application
Ultrasound	I-Application
featured	O
dedicated	O
DSPs	B-Architecture
,	O
which	O
were	O
borrowed	O
from	O
the	O
digital	O
music	O
instruments	O
.	O
</s>
<s>
However	O
,	O
this	O
was	O
only	O
possible	O
in	O
DOS	O
by	O
directly	O
programming	O
the	O
hardware	O
,	O
and	O
full-featured	O
"	O
hardware	B-General_Concept
acceleration	I-General_Concept
"	O
from	O
the	O
local	O
memory	O
was	O
never	O
implemented	O
on	O
these	O
cards	O
,	O
due	O
to	O
complexities	O
of	O
double	O
buffering	O
.	O
</s>
<s>
Later	O
cards	O
such	O
as	O
Sound	O
Blaster	O
Live	O
!,	O
Audigy	B-Device
and	O
X-Fi	B-Device
are	O
capable	O
of	O
accessing	O
the	O
system	O
memory	O
buffers	O
directly	O
.	O
</s>
<s>
DirectSound3D	O
(	O
DS3D	O
)	O
is	O
an	O
extension	O
to	O
DirectSound	B-Device
introduced	O
with	O
DirectX	B-Application
3	O
in	O
1996	O
with	O
the	O
intention	O
to	O
standardize	O
3D	B-Application
audio	I-Application
in	O
Windows	B-Application
.	O
</s>
<s>
DirectSound3D	O
allows	O
software	O
developers	O
to	O
utilize	O
audio	O
by	O
writing	O
once	O
for	O
a	O
single	O
audio	O
API	B-Application
instead	O
of	O
rewriting	O
code	O
numerous	O
times	O
to	O
work	O
for	O
each	O
audio	B-Device
card	I-Device
vendor	O
.	O
</s>
<s>
In	O
DirectX	B-Application
5	O
,	O
DirectSound3D	O
gained	O
the	O
support	O
for	O
sound	B-Device
cards	I-Device
that	O
use	O
third	O
party	O
3D	B-Application
audio	I-Application
algorithms	O
in	O
order	O
to	O
accelerate	B-General_Concept
DirectSound3D	O
properly	O
,	O
through	O
methods	O
approved	O
by	O
Microsoft	O
.	O
</s>
<s>
In	O
DirectX	B-Application
8	I-Application
,	O
DirectSound	B-Device
and	O
DirectSound3D	O
(	O
DS3D	O
)	O
were	O
officially	O
merged	O
and	O
given	O
the	O
name	O
DirectX	B-Application
Audio	O
,	O
however	O
the	O
API	B-Application
is	O
still	O
commonly	O
referred	O
to	O
as	O
DirectSound	B-Device
.	O
</s>
<s>
EAX	O
is	O
an	O
extension	O
to	O
DirectSound	B-Device
and	O
DirectSound3D	O
which	O
provides	O
sound	O
effects	O
processing	O
to	O
the	O
hardware-accelerated	B-General_Concept
buffers	O
.	O
</s>
<s>
In	O
Windows	B-Application
95	O
,	O
98	O
and	O
Me	O
,	O
the	O
DirectSound	B-Device
mixer	O
component	O
and	O
the	O
sound	B-Device
card	I-Device
drivers	O
were	O
both	O
implemented	O
as	O
a	O
kernel-mode	B-Operating_System
VxD	B-Application
driver	O
(	O
Dsound.vxd	O
)	O
,	O
allowing	O
direct	O
access	O
to	O
the	O
primary	O
buffer	O
used	O
by	O
the	O
audio	O
hardware	O
and	O
thus	O
,	O
providing	O
the	O
lowest	O
possible	O
latency	O
between	O
the	O
user-mode	B-Operating_System
API	B-Application
and	O
the	O
underlying	O
hardware	O
,	O
but	O
in	O
some	O
cases	O
causing	O
instability	O
and	O
blue	O
screen	O
errors	O
.	O
</s>
<s>
Windows	B-Application
98	O
introduced	O
WDM	O
Audio	O
and	O
the	O
Kernel	O
Audio	O
Mixer	O
driver	O
(	O
KMixer	O
)	O
,	O
which	O
enabled	O
digital	O
mixing	O
,	O
routing	O
and	O
processing	O
of	O
simultaneous	O
audio	O
streams	O
with	O
a	O
higher	O
quality	O
sample	O
rate	O
conversion	O
as	O
well	O
as	O
kernel	O
streaming	O
.	O
</s>
<s>
Under	O
WDM	O
,	O
DirectSound	B-Device
sends	O
data	O
to	O
the	O
software-based	O
KMixer	O
.	O
</s>
<s>
Windows	B-Application
98	O
Second	O
Edition	O
improved	O
WDM	O
audio	O
support	O
by	O
adding	O
DirectSound	B-Device
hardware	O
buffering	O
,	O
DirectSound3D	O
hardware	O
abstraction	O
,	O
KMixer	O
sample-rate	O
conversion	O
(	O
SRC	O
)	O
for	O
capture	O
streams	O
,	O
multichannel	O
audio	O
support	O
and	O
introduction	O
of	O
DirectMusic	B-Library
.	O
</s>
<s>
If	O
the	O
audio	O
hardware	O
supports	O
hardware	B-General_Concept
mixing	I-General_Concept
(	O
also	O
known	O
as	O
hardware	O
buffering	O
or	O
DirectSound	B-Device
hardware	B-General_Concept
acceleration	I-General_Concept
)	O
,	O
DirectSound	B-Device
buffers	O
directly	O
to	O
the	O
rendering	O
device	O
.	O
</s>
<s>
If	O
DirectSound	B-Device
streams	O
use	O
hardware	B-General_Concept
mixing	I-General_Concept
,	O
KMixer	O
and	O
its	O
latency	O
delay	O
are	O
bypassed	O
.	O
</s>
<s>
On	O
Windows	B-Application
98	O
and	O
Windows	B-Application
Me	O
,	O
WDM	O
audio	O
drivers	O
were	O
preferred	O
but	O
compatibility	O
with	O
VxD	B-Application
driver	O
model	O
was	O
preserved	O
.	O
</s>
<s>
Although	O
Windows	B-Application
Driver	I-Application
Model	I-Application
(	O
WDM	O
)	O
was	O
available	O
starting	O
with	O
Windows	B-Application
98	O
,	O
few	O
audio	B-Device
card	I-Device
manufacturers	O
used	O
it	O
.	O
</s>
<s>
Windows	B-Application
98	O
also	O
includes	O
a	O
WDM	O
streaming	O
class	O
driver	O
(	O
Stream.sys	O
)	O
to	O
address	O
these	O
real	O
time	O
multimedia	O
data	O
stream	O
processing	O
requirements	O
.	O
</s>
<s>
When	O
the	O
sound	B-Device
card	I-Device
uses	O
a	O
custom	O
driver	O
for	O
use	O
with	O
the	O
system	O
supplied	O
port	O
class	O
driver	O
PortCls.sys	O
or	O
implements	O
a	O
mini-driver	O
for	O
use	O
with	O
the	O
streaming	O
class	O
driver	O
,	O
applications	B-Application
can	O
bypass	O
the	O
KMixer	O
completely	O
and	O
use	O
the	O
kernel	O
streaming	O
interfaces	O
instead	O
to	O
reduce	O
latency	O
.	O
</s>
<s>
In	O
Windows	B-Application
2000	O
,	O
Microsoft	O
also	O
implemented	O
the	O
same	O
WDM-based	O
audio	O
stack	O
on	O
Windows	B-Device
NT	I-Device
by	O
introducing	O
the	O
WDM	O
audio	O
drivers	O
and	O
the	O
kernel	O
mixer	O
component	O
(	O
KMixer	O
)	O
.	O
</s>
<s>
In	O
Windows	B-Application
XP	O
,	O
Microsoft	O
introduced	O
another	O
improved	O
kernel	O
streaming	O
class	O
driver	O
,	O
AVStream	O
.	O
</s>
<s>
Beginning	O
with	O
Windows	B-Application
XP	O
,	O
hardware	B-General_Concept
acceleration	I-General_Concept
was	O
also	O
added	O
for	O
DirectSound	B-Device
capture	O
effects	O
processing	O
such	O
as	O
Acoustic	O
Echo	O
Cancellation	O
for	O
USB	O
microphones	O
,	O
noise	O
suppression	O
and	O
array	O
microphone	O
support	O
.	O
</s>
<s>
Windows	B-Application
Vista	O
features	O
a	O
completely	O
re-written	O
audio	O
stack	O
based	O
on	O
the	O
Universal	B-Device
Audio	I-Device
Architecture	I-Device
.	O
</s>
<s>
Because	O
of	O
the	O
architectural	O
changes	O
in	O
the	O
redesigned	O
audio	O
stack	O
,	O
a	O
direct	O
path	O
from	O
DirectSound	B-Device
to	O
the	O
audio	O
drivers	O
does	O
not	O
exist	O
.	O
</s>
<s>
DirectSound	B-Device
,	O
DirectMusic	B-Library
and	O
other	O
APIs	B-Application
such	O
as	O
MME	O
are	O
emulated	O
as	O
WASAPI	O
Session	O
instances	O
.	O
</s>
<s>
DirectSound	B-Device
runs	O
in	O
emulation	O
mode	O
on	O
the	O
Microsoft	O
software	O
mixer	O
.	O
</s>
<s>
The	O
emulator	O
does	O
not	O
have	O
hardware	O
abstraction	O
,	O
so	O
there	O
is	O
no	O
hardware	O
DirectSound	B-Device
acceleration	O
,	O
meaning	O
hardware	O
and	O
software	O
relying	O
on	O
DirectSound	B-Device
acceleration	O
may	O
have	O
degraded	O
performance	O
.	O
</s>
<s>
In	O
the	O
case	O
of	O
hardware	O
3D	B-Application
audio	I-Application
effects	I-Application
played	O
using	O
DirectSound3D	O
,	O
they	O
will	O
not	O
be	O
playable	O
;	O
this	O
also	O
breaks	O
compatibility	O
with	O
EAX	O
extensions	O
.	O
</s>
<s>
Third-party	O
APIs	B-Application
such	O
as	O
ASIO	B-Library
and	O
OpenAL	B-Application
are	O
not	O
affected	O
by	O
these	O
architectural	O
changes	O
in	O
Windows	B-Application
Vista	O
,	O
as	O
they	O
use	O
IOCtl	B-Operating_System
to	O
interface	O
directly	O
with	O
the	O
audio	O
driver	O
.	O
</s>
<s>
A	O
solution	O
for	O
applications	B-Application
that	O
wish	O
to	O
take	O
advantage	O
of	O
hardware	B-General_Concept
accelerated	I-General_Concept
high-quality	O
3D	O
positional	B-Application
audio	I-Application
is	O
to	O
use	O
OpenAL	B-Application
.	O
</s>
<s>
However	O
,	O
this	O
only	O
works	O
if	O
the	O
manufacturer	O
provides	O
an	O
OpenAL	B-Application
driver	O
for	O
their	O
hardware	O
.	O
</s>
<s>
WASAPI	O
audio	O
stack	O
in	O
Windows	B-Application
8	I-Application
introduces	O
support	O
for	O
"	O
hardware	O
offloading	O
"	O
of	O
multiple	O
audio	O
streams	O
to	O
the	O
audio	B-Device
card	I-Device
for	O
mixing	O
and	O
effect	O
processing	O
,	O
in	O
addition	O
to	O
the	O
software	O
processing	O
introduced	O
in	O
Vista	O
,	O
however	O
the	O
functionality	O
is	O
only	O
exposed	O
for	O
Windows	B-Application
Runtime	O
apps	O
.	O
</s>
<s>
DirectSound	B-Device
's	O
and	O
DirectMusic	B-Library
's	O
hardware	O
interfaces	O
to	O
sound	B-Device
card	I-Device
drivers	O
are	O
not	O
implemented	O
.	O
</s>
<s>
Although	O
DirectSound	B-Device
support	O
was	O
available	O
in	O
Windows	B-Operating_System
CE	I-Operating_System
versions	O
up	O
to	O
4.2	O
,	O
it	O
was	O
removed	O
starting	O
5.0	O
.	O
</s>
<s>
Windows	B-Operating_System
CE	I-Operating_System
6.0	O
also	O
does	O
not	O
support	O
DirectSound	B-Device
,	O
instead	O
favoring	O
that	O
applications	B-Application
be	O
rewritten	O
to	O
use	O
the	O
Waveform	O
Audio	O
API	B-Application
.	O
</s>
<s>
After	O
the	O
removal	O
of	O
DirectSound	B-Device
in	O
Windows	B-Application
Vista	O
,	O
a	O
few	O
replacement	O
implementations	O
have	O
appeared	O
.	O
</s>
<s>
Sound	O
Blaster	O
's	O
Creative	O
ALchemy	O
(	O
2007	O
)	O
provides	O
hardware	B-General_Concept
acceleration	I-General_Concept
of	O
DirectSound3D	O
and	O
Audio	O
Effects	O
,	O
such	O
as	O
EAX	O
.	O
</s>
<s>
Creative	O
ALchemy	O
intercepts	O
calls	O
to	O
DirectSound3D	O
and	O
translates	O
them	O
into	O
OpenAL	B-Application
calls	O
to	O
be	O
processed	O
by	O
supported	O
hardware	O
such	O
as	O
Sound	B-Device
Blaster	I-Device
X-Fi	I-Device
and	O
Sound	B-Device
Blaster	I-Device
Audigy	I-Device
.	O
</s>
<s>
For	O
software-based	O
Creative	O
audio	O
solutions	O
,	O
ALchemy	O
utilizes	O
its	O
built-in	O
3D	B-Application
audio	I-Application
engine	O
without	O
using	O
OpenAL	B-Application
at	O
all	O
.	O
</s>
<s>
C-Media	O
,	O
a	O
manufacturer	O
of	O
PC	O
sound	B-Device
card	I-Device
chipsets	O
,	O
also	O
has	O
a	O
solution	O
called	O
Xear3D	O
EX	O
,	O
although	O
it	O
works	O
instead	O
by	O
intercepting	O
DirectSound3D	O
calls	O
transparently	O
in	O
the	O
background	O
without	O
any	O
user	O
intervention	O
.	O
</s>
<s>
IndirectSound	O
is	O
a	O
freeware	O
library	O
that	O
emulates	O
DirectSound	B-Device
3D	O
using	O
XAudio2	B-Device
,	O
without	O
using	O
hardware	B-General_Concept
acceleration	I-General_Concept
.	O
</s>
