<s>
DirectX	B-General_Concept
Video	I-General_Concept
Acceleration	I-General_Concept
(	O
DXVA	B-General_Concept
)	O
is	O
a	O
Microsoft	O
API	B-General_Concept
specification	O
for	O
the	O
Microsoft	B-Application
Windows	I-Application
and	O
Xbox	B-Operating_System
360	I-Operating_System
platforms	O
that	O
allows	O
video	B-Application
decoding	I-Application
to	O
be	O
hardware-accelerated	B-General_Concept
.	O
</s>
<s>
The	O
pipeline	B-Operating_System
allows	O
certain	O
CPU-intensive	O
operations	O
such	O
as	O
iDCT	B-General_Concept
,	O
motion	B-Algorithm
compensation	I-Algorithm
and	O
deinterlacing	O
to	O
be	O
offloaded	O
to	O
the	O
GPU	B-Architecture
.	O
</s>
<s>
DXVA	B-General_Concept
2.0	O
allows	O
more	O
operations	O
,	O
including	O
video	B-General_Concept
capturing	I-General_Concept
and	O
processing	O
operations	O
,	O
to	O
be	O
hardware-accelerated	B-General_Concept
as	O
well	O
.	O
</s>
<s>
DXVA	B-General_Concept
works	O
in	O
conjunction	O
with	O
the	O
video	B-Application
rendering	I-Application
model	O
used	O
by	O
the	O
video	B-Device
card	I-Device
.	O
</s>
<s>
DXVA	B-General_Concept
1.0	O
,	O
which	O
was	O
introduced	O
as	O
a	O
standardized	O
API	B-General_Concept
with	O
Windows	B-Application
2000	I-Application
and	O
is	O
currently	O
available	O
on	O
Windows	B-Device
98	I-Device
or	O
later	O
,	O
can	O
use	O
either	O
the	O
overlay	O
rendering	O
mode	O
or	O
VMR	B-Library
7/9	I-Library
.	O
</s>
<s>
DXVA	B-General_Concept
2.0	O
,	O
available	O
only	O
on	O
Windows	B-Application
Vista	I-Application
,	O
Windows	B-Device
7	I-Device
,	O
Windows	B-Application
8	I-Application
and	O
later	O
OSs	O
,	O
integrates	O
with	O
Media	B-Device
Foundation	I-Device
(	O
MF	O
)	O
and	O
uses	O
the	O
Enhanced	O
Video	B-Application
Renderer	I-Application
(	O
EVR	O
)	O
present	O
in	O
MF	O
.	O
</s>
<s>
The	O
DXVA	B-General_Concept
is	O
used	O
by	O
software	O
video	O
decoders	O
to	O
define	O
a	O
codec-specific	O
pipeline	B-Operating_System
for	O
hardware-accelerated	B-General_Concept
decoding	B-General_Concept
and	O
rendering	O
of	O
the	O
codec	B-General_Concept
.	O
</s>
<s>
The	O
pipeline	B-Operating_System
starts	O
at	O
the	O
CPU	B-Device
which	O
is	O
used	O
for	O
parsing	O
the	O
media	O
stream	O
and	O
conversion	O
to	O
DXVA-compatible	O
structures	O
.	O
</s>
<s>
DXVA	B-General_Concept
specifies	O
a	O
set	O
of	O
operations	O
that	O
can	O
be	O
hardware-accelerated	B-General_Concept
and	O
device	B-Application
driver	I-Application
interfaces	I-Application
(	O
DDIs	O
)	O
that	O
the	O
graphic	O
driver	O
can	O
implement	O
to	O
accelerate	O
the	O
operations	O
.	O
</s>
<s>
If	O
the	O
codec	B-General_Concept
needs	O
to	O
do	O
any	O
of	O
the	O
defined	O
operations	O
,	O
it	O
can	O
use	O
these	O
interfaces	B-Application
to	O
access	O
the	O
hardware-accelerated	B-General_Concept
implementation	O
of	O
these	O
operations	O
.	O
</s>
<s>
If	O
the	O
graphic	O
driver	O
does	O
not	O
implement	O
one	O
or	O
more	O
of	O
the	O
interfaces	B-Application
,	O
it	O
is	O
up	O
to	O
the	O
codec	B-General_Concept
to	O
provide	O
a	O
software	O
fallback	O
for	O
it	O
.	O
</s>
<s>
The	O
decoded	O
video	O
is	O
handed	O
over	O
to	O
the	O
hardware	O
video	B-Application
renderer	I-Application
,	O
where	O
further	O
video	O
post-processing	O
might	O
be	O
applied	O
to	O
it	O
before	O
being	O
rendered	O
to	O
the	O
device	O
.	O
</s>
<s>
The	O
resulting	O
pipeline	B-Operating_System
is	O
usable	O
in	O
a	O
DirectShow-compatible	O
application	O
.	O
</s>
<s>
DXVA	B-General_Concept
specifies	O
the	O
Motion	B-Algorithm
Compensation	I-Algorithm
DDI	O
,	O
which	O
specifies	O
the	O
interfaces	B-Application
for	O
iDCT	B-General_Concept
operations	O
,	O
Huffman	B-General_Concept
coding	I-General_Concept
,	O
motion	B-Algorithm
compensation	I-Algorithm
,	O
alpha	B-Algorithm
blending	I-Algorithm
,	O
inverse	O
quantization	B-Algorithm
,	O
color	O
space	O
conversion	O
and	O
frame-rate	O
conversion	O
operations	O
,	O
among	O
others	O
.	O
</s>
<s>
The	O
COPP	O
(	O
Certified	O
Output	O
Protection	O
Protocol	O
)	O
DDI	O
functions	O
allow	O
the	O
pipeline	B-Operating_System
to	O
be	O
secured	O
for	O
DRM-protected	O
media	O
,	O
by	O
specifying	O
encryption	O
functions	O
.	O
</s>
<s>
The	O
ProcAmp	O
driver	O
module	O
sits	O
between	O
the	O
hardware	O
video	B-Application
renderer	I-Application
and	O
the	O
display	O
driver	O
,	O
and	O
it	O
provides	O
functions	O
for	O
applying	O
post-processing	O
filters	O
on	O
the	O
decompressed	O
video	O
.	O
</s>
<s>
The	O
functions	O
exposed	O
by	O
DXVA	B-General_Concept
DDIs	O
are	O
not	O
accessible	O
directly	O
by	O
a	O
DirectShow	B-Library
client	O
,	O
but	O
are	O
supplied	O
as	O
callback	O
functions	O
to	O
the	O
video	B-Application
renderer	I-Application
.	O
</s>
<s>
As	O
such	O
,	O
the	O
renderer	O
plays	O
a	O
very	O
important	O
role	O
in	O
anchoring	O
the	O
pipeline	B-Operating_System
.	O
</s>
<s>
DXVA	B-General_Concept
2.0	O
enhances	O
the	O
implementation	O
of	O
the	O
video	O
pipeline	B-Operating_System
and	O
adds	O
a	O
host	O
of	O
other	O
DDIs	O
,	O
including	O
a	O
Capture	O
DDI	O
for	O
video	B-General_Concept
capture	I-General_Concept
.	O
</s>
<s>
The	O
DDIs	O
it	O
shares	O
with	O
DXVA	B-General_Concept
1.0	O
are	O
also	O
enhanced	O
with	O
the	O
ability	O
to	O
use	O
hardware	B-General_Concept
acceleration	I-General_Concept
of	O
more	O
operations	O
.	O
</s>
<s>
Also	O
,	O
the	O
DDI	O
functions	O
are	O
directly	O
available	O
to	O
callers	O
and	O
need	O
not	O
be	O
mediated	O
by	O
the	O
video	B-Application
renderer	I-Application
.	O
</s>
<s>
As	O
such	O
,	O
a	O
program	O
can	O
also	O
create	O
a	O
pipeline	B-Operating_System
for	O
simply	O
decoding	B-General_Concept
the	O
media	O
(	O
without	O
rendering	O
)	O
or	O
post-processing	O
and	O
rendering	O
(	O
without	O
decoding	B-General_Concept
)	O
.	O
</s>
<s>
These	O
features	O
require	O
the	O
Windows	B-Device
Display	I-Device
Driver	I-Device
Model	I-Device
drivers	O
,	O
which	O
limits	O
DXVA	B-General_Concept
2.0	O
to	O
Windows	B-Application
Vista	I-Application
,	O
Windows	B-Device
Server	I-Device
2008	I-Device
,	O
Windows	B-Device
7	I-Device
,	O
Windows	B-Device
Server	I-Device
2008	I-Device
R2	I-Device
and	O
Windows	B-Application
8	I-Application
.	O
</s>
<s>
On	O
Windows	B-Application
XP	I-Application
and	O
Windows	B-Application
2000	I-Application
,	O
programs	O
can	O
use	O
DXVA	B-General_Concept
1.0	O
.	O
</s>
<s>
DXVA	B-General_Concept
2.0	O
allows	O
Enhanced	O
Video	B-Application
Renderer	I-Application
as	O
the	O
video	B-Application
renderer	I-Application
only	O
on	O
Vista	B-Application
,	O
Windows	B-Device
7	I-Device
,	O
and	O
Windows	B-Application
8	I-Application
.	O
</s>
<s>
(	O
With	O
Windows	B-Application
XP	I-Application
,	O
DXVA-Rendering	O
is	O
possible	O
with	O
VMR9	B-Library
and	O
the	O
well-known	O
Overlay	O
Mixer	O
.	O
)	O
</s>
<s>
DXVA	B-General_Concept
integrates	O
with	O
Media	B-Device
Foundation	I-Device
and	O
allows	O
DXVA	B-General_Concept
pipelines	B-Operating_System
to	O
be	O
exposed	O
as	O
Media	B-Device
Foundation	I-Device
Transforms	O
(	O
MFTs	O
)	O
.	O
</s>
<s>
Even	O
decoder	O
pipelines	B-Operating_System
or	O
post-processing	O
pipelines	B-Operating_System
can	O
be	O
exposed	O
as	O
MFTs	O
,	O
which	O
can	O
be	O
used	O
by	O
the	O
Media	B-Device
Foundation	I-Device
topology	O
loader	O
to	O
create	O
a	O
full	O
media	O
playback	O
pipeline	B-Operating_System
.	O
</s>
<s>
DXVA	B-General_Concept
1.0	O
is	O
emulated	O
using	O
DXVA	B-General_Concept
2.0	O
.	O
</s>
<s>
DXVA	B-General_Concept
2.0	O
does	O
not	O
include	O
the	O
COPP	O
DDI	O
,	O
rather	O
it	O
uses	O
PVP	O
for	O
protected	O
content	O
.	O
</s>
<s>
Windows	B-Device
7	I-Device
implements	O
DXVA-HD	O
if	O
the	O
driver	O
complies	O
with	O
WDDM	B-Device
1.1	O
.	O
</s>
<s>
With	O
native	O
implementation	O
,	O
the	O
decoded	O
video	O
stays	O
in	O
GPU	B-Architecture
memory	O
until	O
it	O
has	O
been	O
displayed	O
.	O
</s>
<s>
The	O
video	O
decoder	O
must	O
be	O
connected	O
to	O
the	O
video	B-Application
renderer	I-Application
with	O
no	O
intermediary	O
processing	O
filter	O
.	O
</s>
<s>
The	O
video	B-Application
renderer	I-Application
must	O
also	O
support	O
DXVA	B-General_Concept
,	O
which	O
gives	O
less	O
freedom	O
in	O
the	O
choice	O
of	O
renderers	O
.	O
</s>
<s>
With	O
copy-back	O
implementation	O
,	O
the	O
decoded	O
video	O
is	O
copied	O
from	O
GPU	B-Architecture
memory	O
back	O
to	O
the	O
CPU	B-Device
's	O
memory	O
.	O
</s>
<s>
This	O
implementation	O
does	O
n't	O
have	O
the	O
limitations	O
mentioned	O
above	O
and	O
acts	O
similarly	O
to	O
a	O
normal	O
software	O
decoder	O
;	O
however	O
,	O
video	O
stuttering	O
will	O
occur	O
if	O
the	O
GPU	B-Architecture
is	O
not	O
fast	O
enough	O
to	O
copy	O
its	O
memory	O
back	O
to	O
the	O
CPU	B-Device
's	O
memory	O
.	O
</s>
<s>
Native	O
mode	O
is	O
advantageous	O
unless	O
there	O
is	O
a	O
need	O
for	O
customized	O
processing	O
,	O
as	O
the	O
additional	O
copy-back	O
operations	O
will	O
increase	O
GPU	B-Architecture
memory	O
load	O
.	O
</s>
