<s>
A	O
media	B-Application
server	I-Application
is	O
a	O
computer	B-Architecture
appliance	I-Architecture
or	O
an	O
application	B-Application
software	I-Application
that	O
stores	O
digital	O
media	O
(	O
video	O
,	O
audio	O
or	O
images	O
)	O
and	O
makes	O
it	O
available	O
over	O
a	O
network	O
.	O
</s>
<s>
Media	B-Application
servers	I-Application
range	O
from	O
servers	B-Application
that	O
provide	O
video	B-Application
on	I-Application
demand	I-Application
to	O
smaller	O
personal	B-Device
computers	I-Device
or	O
NAS	B-Application
(	O
Network	B-Application
Attached	I-Application
Storage	I-Application
)	O
for	O
the	O
home	O
.	O
</s>
<s>
By	O
definition	O
,	O
a	O
media	B-Application
server	I-Application
is	O
a	O
device	O
that	O
simply	O
stores	O
and	O
shares	O
media	O
.	O
</s>
<s>
This	O
definition	O
is	O
vague	O
,	O
and	O
can	O
allow	O
several	O
different	O
devices	O
to	O
be	O
called	O
media	B-Application
servers	I-Application
.	O
</s>
<s>
It	O
may	O
be	O
a	O
NAS	B-Application
drive	I-Application
,	O
a	O
home	O
theater	O
PC	O
running	O
Windows	O
XP	O
Media	O
Center	O
Edition	O
,	O
MediaPortal	B-Application
or	O
MythTV	B-Application
,	O
or	O
a	O
commercial	O
web	B-Application
server	I-Application
that	O
hosts	O
media	O
for	O
a	O
large	O
web	O
site	O
.	O
</s>
<s>
In	O
a	O
home	O
setting	O
,	O
a	O
media	B-Application
server	I-Application
acts	O
as	O
an	O
aggregator	O
of	O
information	O
:	O
video	O
,	O
audio	O
,	O
photos	O
,	O
books	O
,	O
etc	O
.	O
</s>
<s>
These	O
different	O
types	O
of	O
media	O
(	O
whether	O
they	O
originated	O
on	O
DVD	O
,	O
CD	O
,	O
digital	B-Device
camera	I-Device
,	O
or	O
in	O
physical	O
form	O
)	O
are	O
stored	O
on	O
the	O
media	B-Application
server	I-Application
's	O
hard	B-Device
drive	I-Device
.	O
</s>
<s>
The	O
only	O
requirement	O
for	O
a	O
media	B-Application
server	I-Application
is	O
a	O
method	O
of	O
storing	O
media	O
and	O
a	O
network	O
connection	O
with	O
enough	O
bandwidth	O
to	O
allow	O
access	O
to	O
that	O
media	O
.	O
</s>
<s>
Depending	O
on	O
the	O
uses	O
and	O
applications	O
that	O
it	O
runs	O
,	O
a	O
media	B-Application
server	I-Application
may	O
require	O
large	O
amounts	O
of	O
RAM	B-Architecture
,	O
or	O
a	O
powerful	O
multicore	B-Architecture
CPU	I-Architecture
.	O
</s>
<s>
A	O
RAID	B-Architecture
array	I-Architecture
may	O
be	O
used	O
to	O
create	O
a	O
large	O
amount	O
of	O
storage	O
,	O
though	O
it	O
is	O
generally	O
not	O
necessary	O
in	O
a	O
home	O
media	B-Application
server	I-Application
to	O
use	O
a	O
RAID	B-Architecture
array	I-Architecture
that	O
gives	O
a	O
performance	O
increase	O
because	O
current	O
home	O
network	O
transfer	O
speeds	O
are	O
slower	O
than	O
that	O
of	O
most	O
current	O
hard	B-Device
drives	I-Device
.	O
</s>
<s>
However	O
,	O
a	O
RAID	B-Architecture
configuration	O
may	O
be	O
used	O
to	O
prevent	O
loss	O
of	O
the	O
media	O
files	O
due	O
to	O
disk	O
failure	O
as	O
well	O
.	O
</s>
<s>
Many	O
media	B-Application
servers	I-Application
also	O
have	O
the	O
ability	O
to	O
capture	O
media	O
.	O
</s>
<s>
This	O
analog	O
video	O
then	O
needs	O
to	O
be	O
encoded	O
in	O
digital	O
format	O
to	O
be	O
stored	O
on	O
the	O
media	B-Application
server	I-Application
.	O
</s>
<s>
This	O
encoding	O
can	O
be	O
done	O
with	O
software	O
running	O
on	O
the	O
Media	B-Application
server	I-Application
computer	O
or	O
by	O
hardware	O
on	O
the	O
TV	O
tuner	O
card	O
.	O
</s>
<s>
The	O
growing	O
use	O
of	O
motion	O
graphics	O
in	O
environments	O
such	O
as	O
theatre	O
,	O
dance	O
,	O
corporate	O
events	O
and	O
concerts	O
has	O
led	O
to	O
the	O
development	O
of	O
media	B-Application
servers	I-Application
designed	O
specifically	O
for	O
live	O
events	O
.	O
</s>
<s>
These	O
machines	O
are	O
often	O
high-spec	O
PC	O
computers	O
with	O
high-speed	O
hard	B-Device
drive	I-Device
technologies	O
such	O
as	O
RAID	B-Architecture
arrays	I-Architecture
or	O
solid-state	B-Device
drives	I-Device
,	O
multiple	O
GPUs	O
and	O
optionally	O
a	O
video	O
capture	O
board	O
to	O
allow	O
mixing	O
live	O
video	O
with	O
recorded	O
content	O
and	O
real-time	O
effects	O
.	O
</s>
<s>
High-end	O
media	B-Application
server	I-Application
systems	O
include	O
support	O
for	O
DMX512-A	O
,	O
MIDI	O
,	O
Art-Net	B-Protocol
or	O
similar	O
control	O
protocols	O
to	O
allow	O
multiple	O
remote	O
sources	O
like	O
sliders	O
,	O
buttons	O
and	O
knobs	O
on	O
a	O
control	O
console	O
to	O
drive	O
these	O
parameters	O
,	O
as	O
well	O
as	O
sending	O
commands	O
from	O
the	O
media	B-Application
server	I-Application
to	O
for	O
instance	O
control	O
RGB	O
or	O
moving	O
lighting	O
and	O
other	O
stage	O
effects	O
.	O
</s>
<s>
A	O
major	O
feature	O
of	O
high-end	O
media	B-Application
servers	I-Application
is	O
projection	O
mapping	O
,	O
where	O
multiple	O
video	O
projectors	O
can	O
project	O
images	O
onto	O
irregularly	O
shaped	O
and	O
positioned	O
set	O
pieces	O
and	O
even	O
track	O
their	O
motion	O
.	O
</s>
<s>
In	O
the	O
world	O
of	O
telephony	O
,	O
a	O
media	B-Application
server	I-Application
is	O
the	O
computing	O
component	O
that	O
processes	O
the	O
audio	O
or	O
video	B-Application
streams	I-Application
associated	O
with	O
telephone	O
calls	O
or	O
connections	O
.	O
</s>
<s>
Conference	O
services	O
are	O
a	O
particular	O
example	O
of	O
how	O
media	B-Application
servers	I-Application
can	O
be	O
used	O
,	O
as	O
a	O
special	O
'	O
engine	O
 '	O
is	O
needed	O
to	O
mix	O
audio	O
streams	O
together	O
so	O
that	O
conference	O
participants	O
can	O
hear	O
all	O
of	O
the	O
other	O
participants	O
.	O
</s>
<s>
Conferencing	O
servers	B-Application
may	O
also	O
need	O
other	O
specialized	O
functions	O
like	O
"	O
loudest	O
talker	O
"	O
detection	O
,	O
or	O
transcoding	B-Device
of	O
audio	O
streams	O
,	O
and	O
also	O
interpreting	O
DTMF	O
tones	O
used	O
to	O
navigate	O
menus	O
.	O
</s>
<s>
For	O
video	O
processing	O
,	O
it	O
may	O
be	O
needed	O
to	O
change	O
video	B-Application
streams	I-Application
,	O
for	O
example	O
transcode	B-Device
from	O
one	O
video	O
codec	O
to	O
another	O
or	O
rescale	O
a	O
picture	O
from	O
one	O
size	O
to	O
another	O
.	O
</s>
<s>
These	O
media	O
processing	O
functions	O
are	O
the	O
core	O
responsibility	O
of	O
a	O
media	B-Application
server	I-Application
.	O
</s>
<s>
With	O
telephony	O
networks	O
moving	O
towards	O
VoIP	B-Application
technology	O
,	O
and	O
using	O
Session	B-Application
Initiation	I-Application
Protocol	I-Application
(	O
SIP	O
)	O
,	O
the	O
idea	O
of	O
media	B-Application
servers	I-Application
has	O
started	O
to	O
gain	O
some	O
traction	O
.	O
</s>
<s>
Typically	O
,	O
an	O
application	O
(	O
the	O
'	O
application	O
server	O
 '	O
)	O
has	O
the	O
controlling	O
logic	O
,	O
and	O
controls	O
a	O
remote	O
media	B-Application
server	I-Application
(	O
or	O
multiple	O
servers	B-Application
)	O
over	O
an	O
IP	B-Protocol
connection	O
,	O
possibly	O
using	O
SIP	O
.	O
</s>
<s>
Protocols	O
such	O
as	O
Netann	O
,	O
MSCML	B-Language
and	O
MSML	B-Language
have	O
been	O
created	O
for	O
this	O
way	O
of	O
working	O
,	O
and	O
a	O
new	O
protocol	O
,	O
MediaCTRL	O
,	O
is	O
under	O
development	O
at	O
the	O
IETF	O
.	O
</s>
<s>
The	O
IP	B-Protocol
Multimedia	I-Protocol
Subsystem	I-Protocol
(	O
IMS	O
)	O
,	O
the	O
blueprint	O
for	O
next	O
generation	O
networks	O
,	O
defines	O
a	O
component	O
called	O
the	O
MRF	O
(	O
Media	O
Resource	O
Function	O
)	O
,	O
which	O
is	O
a	O
kind	O
of	O
media	B-Application
server	I-Application
.	O
</s>
<s>
Media	B-Application
servers	I-Application
in	O
cinema	O
allow	O
users	O
to	O
download	O
and	O
watch	O
high	O
quality	O
content	O
by	O
utilizing	O
a	O
movie	O
player	O
and	O
plugging	O
into	O
a	O
display	O
or	O
AV	O
system	O
.	O
</s>
