<s>
An	O
audio	B-Algorithm
codec	I-Algorithm
is	O
a	O
device	O
or	O
computer	O
program	O
capable	O
of	O
encoding	O
or	O
decoding	O
a	O
digital	O
data	O
stream	O
(	O
a	O
codec	B-General_Concept
)	O
that	O
encodes	O
or	O
decodes	O
audio	O
.	O
</s>
<s>
In	O
software	O
,	O
an	O
audio	B-Algorithm
codec	I-Algorithm
is	O
a	O
computer	O
program	O
implementing	O
an	O
algorithm	O
that	O
compresses	O
and	O
decompresses	O
digital	O
audio	O
data	O
according	O
to	O
a	O
given	O
audio	O
file	O
or	O
streaming	O
media	O
audio	O
coding	O
format	O
.	O
</s>
<s>
Most	O
software	B-General_Concept
codecs	I-General_Concept
are	O
implemented	O
as	O
libraries	B-Library
which	O
interface	O
to	O
one	O
or	O
more	O
multimedia	O
players	O
.	O
</s>
<s>
Most	O
modern	O
audio	O
compression	O
algorithms	O
are	O
based	O
on	O
modified	O
discrete	O
cosine	O
transform	O
(	O
MDCT	O
)	O
coding	O
and	O
linear	B-Algorithm
predictive	I-Algorithm
coding	I-Algorithm
(	O
LPC	O
)	O
.	O
</s>
<s>
In	O
hardware	O
,	O
audio	B-Algorithm
codec	I-Algorithm
refers	O
to	O
a	O
single	O
device	O
that	O
encodes	O
analog	O
audio	O
as	O
digital	O
signals	O
and	O
decodes	O
digital	O
back	O
into	O
analog	O
.	O
</s>
<s>
This	O
is	O
used	O
in	O
sound	B-Device
cards	I-Device
that	O
support	O
both	O
audio	O
in	O
and	O
out	O
,	O
for	O
instance	O
.	O
</s>
<s>
Hardware	O
audio	B-Algorithm
codecs	I-Algorithm
send	O
and	O
receive	O
digital	O
data	O
using	O
buses	B-General_Concept
such	O
as	O
AC-Link	O
,	O
I²S	O
,	O
SPI	B-Architecture
,	O
I²C	O
,	O
etc	O
.	O
</s>
<s>
Most	O
commonly	O
the	O
digital	O
data	O
is	O
linear	B-Algorithm
PCM	I-Algorithm
,	O
and	O
this	O
is	O
the	O
only	O
format	O
that	O
most	O
codecs	B-General_Concept
support	O
,	O
but	O
some	O
legacy	O
codecs	B-General_Concept
support	O
other	O
formats	O
such	O
as	O
G.711	B-Algorithm
for	O
telephony	O
.	O
</s>
