<s>
libavcodec	B-Language
is	O
a	O
free	B-License
and	I-License
open-source	I-License
library	B-Library
of	O
codecs	B-General_Concept
for	O
encoding	O
and	O
decoding	O
video	B-Algorithm
and	O
audio	O
data	O
.	O
</s>
<s>
libavcodec	B-Language
is	O
an	O
integral	O
part	O
of	O
many	O
open-source	O
multimedia	O
applications	O
and	O
frameworks	O
.	O
</s>
<s>
The	O
popular	O
MPV	B-Language
,	O
xine	B-Application
and	O
VLC	B-Application
media	I-Application
players	I-Application
use	O
it	O
as	O
their	O
main	O
,	O
built-in	O
decoding	O
engine	O
that	O
enables	O
playback	O
of	O
many	O
audio	O
and	O
video	B-Algorithm
formats	O
on	O
all	O
supported	O
platforms	O
.	O
</s>
<s>
It	O
is	O
also	O
used	O
by	O
the	O
ffdshow	B-Language
tryouts	I-Language
decoder	O
as	O
its	O
primary	O
decoding	O
library	B-Library
.	O
</s>
<s>
libavcodec	B-Language
is	O
also	O
used	O
in	O
video	B-Algorithm
editing	O
and	O
transcoding	O
applications	O
like	O
Avidemux	B-Language
,	O
MEncoder	B-Language
or	O
Kdenlive	B-Language
for	O
both	O
decoding	O
and	O
encoding	O
.	O
</s>
<s>
libavcodec	B-Language
contains	O
decoder	O
and	O
sometimes	O
encoder	O
implementations	O
of	O
several	O
proprietary	O
formats	O
,	O
including	O
ones	O
for	O
which	O
no	O
public	O
specification	O
has	O
been	O
released	O
.	O
</s>
<s>
As	O
such	O
,	O
a	O
significant	O
reverse	O
engineering	O
effort	O
is	O
part	O
of	O
libavcodec	B-Language
development	O
.	O
</s>
<s>
Having	O
such	O
codecs	B-General_Concept
available	O
within	O
the	O
standard	O
libavcodec	B-Language
framework	O
gives	O
a	O
number	O
of	O
benefits	O
over	O
using	O
the	O
original	O
codecs	B-General_Concept
,	O
most	O
notably	O
increased	O
portability	B-Architecture
,	O
and	O
in	O
some	O
cases	O
also	O
better	O
performance	O
,	O
since	O
libavcodec	B-Language
contains	O
a	O
standard	O
library	B-Library
of	O
highly	O
optimized	O
implementations	O
of	O
common	O
building	O
blocks	O
,	O
such	O
as	O
DCT	B-General_Concept
and	O
color	B-Algorithm
space	I-Algorithm
conversion	I-Algorithm
.	O
</s>
<s>
However	O
,	O
while	O
libavcodec	B-Language
does	O
strive	O
to	O
achieve	O
decoding	O
that	O
is	O
bit-exact	O
to	O
their	O
official	O
format	O
implementations	O
,	O
occasional	O
bugs	O
and	O
missing	O
features	O
in	O
such	O
re-implementations	O
can	O
sometimes	O
introduce	O
playback	O
compatibility	O
problems	O
for	O
certain	O
files	O
.	O
</s>
<s>
libavcodec	B-Language
includes	O
video	B-Algorithm
decoders	O
and/or	O
encoders	O
for	O
the	O
following	O
formats	O
,	O
this	O
list	O
is	O
not	O
exhaustive	O
:	O
</s>
<s>
libavcodec	B-Language
includes	O
decoders	O
and	O
encoders	O
for	O
the	O
following	O
formats	O
:	O
</s>
<s>
Libavcodec	B-Language
contains	O
more	O
than	O
100	O
codecs	B-General_Concept
,	O
most	O
of	O
which	O
do	O
not	O
just	O
store	O
uncompressed	O
data	O
.	O
</s>
<s>
Most	O
codecs	B-General_Concept
that	O
compress	O
information	O
could	O
be	O
claimed	O
by	O
patent	O
holders	O
.	O
</s>
<s>
Furthermore	O
,	O
many	O
of	O
these	O
codecs	B-General_Concept
are	O
only	O
released	O
under	O
terms	O
that	O
forbid	O
reverse	O
engineering	O
,	O
even	O
for	O
purposes	O
of	O
interoperability	O
.	O
</s>
<s>
ffdshow	B-Language
(	O
wraps	O
libavcodec	B-Language
as	O
a	O
DirectShow	B-Library
filter	O
and	O
adds	O
postprocessing	O
to	O
improve	O
image	O
quality	O
;	O
once	O
installed	O
,	O
it	O
is	O
automatically	O
used	O
by	O
all	O
Windows	O
DirectShow	B-Library
video	B-Algorithm
players	O
,	O
such	O
as	O
Windows	B-Device
Media	I-Device
Player	I-Device
,	O
Media	B-Language
Player	I-Language
Classic	I-Language
,	O
Winamp	B-Application
etc	O
.	O
</s>
<s>
It	O
also	O
wraps	O
libavcodec	B-Language
as	O
a	O
Video	B-Device
for	I-Device
Windows	I-Device
filter	O
;	O
the	O
framework	O
used	O
by	O
most	O
video	B-Algorithm
editing	O
software	O
.	O
)	O
</s>
<s>
osu	B-Application
!	I-Application
</s>
