<s>
Libav	B-Language
is	O
an	O
abandoned	O
free	B-Application
software	I-Application
project	O
,	O
forked	B-Application
from	O
FFmpeg	B-Library
in	O
2011	O
,	O
that	O
contains	O
libraries	B-Library
and	O
programs	B-Application
for	O
handling	O
multimedia	O
data	O
.	O
</s>
<s>
The	O
Libav	B-Language
project	O
was	O
a	O
fork	B-Application
of	O
the	O
FFmpeg	B-Library
project	O
.	O
</s>
<s>
It	O
was	O
announced	O
on	O
March	O
13	O
,	O
2011	O
by	O
a	O
group	O
of	O
FFmpeg	B-Library
developers	O
.	O
</s>
<s>
The	O
event	O
was	O
related	O
to	O
an	O
issue	O
in	O
project	O
management	O
and	O
different	O
goals	O
:	O
FFmpeg	B-Library
supporters	O
wanted	O
to	O
keep	O
development	O
velocity	O
in	O
favour	O
of	O
more	O
features	O
,	O
while	O
Libav	B-Language
supporters	O
and	O
developers	O
wanted	O
to	O
improve	O
the	O
state	O
of	O
the	O
code	O
and	O
take	O
the	O
time	O
to	O
design	O
better	O
APIs	O
.	O
</s>
<s>
The	O
maintainer	O
of	O
the	O
FFmpeg	B-Library
packages	O
for	O
Debian	O
and	O
Ubuntu	B-Operating_System
,	O
being	O
one	O
of	O
the	O
group	O
of	O
developers	O
who	O
forked	B-Application
FFmpeg	B-Library
,	O
switched	O
the	O
packages	O
to	O
this	O
fork	B-Application
in	O
2011	O
.	O
</s>
<s>
Hence	O
,	O
most	O
software	O
on	O
these	O
systems	O
that	O
depended	O
on	O
FFmpeg	B-Library
automatically	O
switched	O
to	O
Libav	B-Language
.	O
</s>
<s>
On	O
July	O
8	O
,	O
2015	O
,	O
Debian	O
announced	O
it	O
would	O
return	O
to	O
FFmpeg	B-Library
for	O
various	O
,	O
technical	O
reasons	O
.	O
</s>
<s>
Firstly	O
,	O
FFmpeg	B-Library
had	O
a	O
better	O
record	O
of	O
responding	O
to	O
vulnerabilities	O
than	O
Libav	B-Language
.	O
</s>
<s>
Secondly	O
,	O
Mateusz	O
"	O
j00ru	O
"	O
Jurczyk	O
,	O
a	O
security-oriented	O
developer	O
at	O
Google	O
,	O
argued	O
that	O
all	O
issues	O
he	O
found	O
in	O
FFmpeg	B-Library
were	O
fixed	O
in	O
a	O
timely	O
manner	O
,	O
while	O
Libav	B-Language
was	O
still	O
affected	O
by	O
various	O
bugs	O
.	O
</s>
<s>
Finally	O
,	O
FFmpeg	B-Library
supported	O
a	O
far	O
wider	O
variety	O
of	O
codecs	B-General_Concept
and	O
containers	O
than	O
Libav	B-Language
.	O
</s>
<s>
Libav	B-Language
is	O
an	O
abandoned	O
software	O
project	O
,	O
with	O
Libav	B-Language
developers	O
either	O
returning	O
to	O
FFmpeg	B-Library
,	O
moving	O
to	O
other	O
multimedia	O
projects	O
like	O
the	O
AV1	B-Application
video	O
codec	B-General_Concept
,	O
or	O
leaving	O
the	O
multimedia	O
field	O
entirely	O
.	O
</s>
<s>
At	O
the	O
beginning	O
of	O
this	O
fork	B-Application
,	O
Libav	B-Language
and	O
FFmpeg	B-Library
separately	O
developed	O
their	O
own	O
versions	O
of	O
the	O
ffmpeg	B-Library
command	O
.	O
</s>
<s>
Libav	B-Language
then	O
renamed	O
their	O
ffmpeg	B-Library
to	O
avconv	B-Language
to	O
distance	O
themselves	O
from	O
the	O
FFmpeg	B-Library
project	O
.	O
</s>
<s>
During	O
the	O
transition	O
period	O
,	O
when	O
a	O
Libav	B-Language
user	O
typed	O
ffmpeg	B-Library
,	O
there	O
was	O
a	O
message	O
telling	O
the	O
user	O
that	O
the	O
ffmpeg	B-Library
command	O
was	O
deprecated	O
and	O
avconv	B-Language
has	O
to	O
be	O
used	O
instead	O
.	O
</s>
<s>
This	O
confused	O
some	O
users	O
into	O
thinking	O
that	O
FFmpeg	B-Library
(	O
the	O
project	O
)	O
was	O
dead	O
.	O
</s>
<s>
This	O
message	O
was	O
removed	O
upstream	B-General_Concept
when	O
ffmpeg	B-Library
was	O
finally	O
removed	O
from	O
the	O
Libav	B-Language
sources	O
.	O
</s>
<s>
In	O
June	O
2012	O
,	O
on	O
Ubuntu	B-Operating_System
12.04	O
,	O
the	O
message	O
was	O
re-worded	O
,	O
but	O
that	O
new	O
"	O
deprecated	O
"	O
message	O
caused	O
even	O
more	O
user	O
confusion	O
.	O
</s>
<s>
Starting	O
with	O
Ubuntu	B-Operating_System
15.04	O
"	O
Vivid	O
"	O
,	O
FFmpeg	B-Library
's	O
ffmpeg	B-Library
is	O
back	O
in	O
the	O
repositories	O
again	O
.	O
</s>
<s>
To	O
further	O
complicate	O
matters	O
,	O
Libav	B-Language
chose	O
a	O
name	O
that	O
was	O
used	O
by	O
FFmpeg	B-Library
to	O
refer	O
to	O
its	O
libraries	B-Library
(	O
libavcodec	B-Language
,	O
libavformat	B-Library
,	O
etc	O
.	O
)	O
.	O
</s>
<s>
For	O
example	O
,	O
the	O
libav-user	O
mailing	O
list	O
,	O
for	O
questions	O
and	O
discussions	O
about	O
using	O
the	O
FFmpeg	B-Library
libraries	B-Library
,	O
is	O
unrelated	O
to	O
the	O
Libav	B-Language
project	O
.	O
</s>
<s>
Debian	O
followed	O
Libav	B-Language
when	O
it	O
was	O
announced	O
,	O
and	O
announced	O
it	O
would	O
return	O
to	O
FFmpeg	B-Library
for	O
Debian	O
Stretch	O
(	O
9.0	O
)	O
.	O
</s>
<s>
MPlayer2	O
,	O
a	O
defunct	O
fork	B-Application
of	O
MPlayer	B-Application
,	O
used	O
Libav	B-Language
exclusively	O
,	O
but	O
could	O
be	O
used	O
with	O
GStreamer	B-Language
with	O
its	O
public	O
API	O
.	O
</s>
<s>
The	O
MPV	B-Language
media	B-Device
player	I-Device
no	O
longer	O
supports	O
Libav	B-Language
due	O
to	O
missing	O
API	O
changes	O
.	O
</s>
<s>
Libav	B-Language
contains	O
more	O
than	O
100	O
codecs	B-General_Concept
.	O
</s>
<s>
Many	O
codecs	B-General_Concept
that	O
compress	O
information	O
have	O
been	O
claimed	O
by	O
patent	O
holders	O
.	O
</s>
<s>
The	O
Libav	B-Language
logo	O
uses	O
a	O
zigzag	O
pattern	O
that	O
references	O
how	O
MPEG	O
video	O
codecs	B-General_Concept
handle	O
entropy	B-Algorithm
encoding	I-Algorithm
.	O
</s>
<s>
It	O
was	O
previously	O
the	O
logo	O
of	O
the	O
FFmpeg	B-Library
project	O
until	O
Libav	B-Language
was	O
forked	B-Application
from	O
it	O
.	O
</s>
<s>
Following	O
the	O
fork	B-Application
,	O
in	O
2011	O
one	O
of	O
the	O
Libav	B-Language
developers	O
Måns	O
Rullgård	O
claimed	O
copyright	O
over	O
the	O
logo	O
and	O
requested	O
FFmpeg	B-Library
cease	O
and	O
desist	O
from	O
using	O
it	O
.	O
</s>
<s>
FFmpeg	B-Library
subsequently	O
altered	O
their	O
logo	O
into	O
a	O
3D	O
version	O
.	O
</s>
<s>
Libav	B-Language
participated	O
in	O
the	O
Google	B-Application
Summer	I-Application
of	I-Application
Code	I-Application
program	O
in	O
2011	O
and	O
2012	O
.	O
</s>
<s>
With	O
participation	O
in	O
the	O
Google	B-Application
Summer	I-Application
of	I-Application
Code	I-Application
,	O
Libav	B-Language
has	O
had	O
many	O
new	O
features	O
and	O
improvements	O
developed	O
,	O
including	O
a	O
WMVP/WVP2	O
decoder	O
,	O
hardware	O
accelerated	O
H.264	B-Application
decoding	O
on	O
Android	B-Application
,	O
and	O
G.723.1	B-Algorithm
codec	B-General_Concept
support	O
.	O
</s>
<s>
Libav	B-Language
primarily	O
consists	O
of	O
libavcodec	B-Language
,	O
which	O
is	O
an	O
audio/video	O
codec	B-General_Concept
library	O
used	O
by	O
several	O
other	O
projects	O
,	O
libavformat	B-Library
,	O
which	O
is	O
an	O
audio/video	O
container	O
muxing	B-Architecture
and	I-Architecture
demuxing	I-Architecture
library	O
,	O
and	O
avconv	B-Language
,	O
which	O
is	O
a	O
multimedia	O
manipulation	O
tool	O
similar	O
to	O
FFmpeg	B-Library
's	O
ffmpeg	B-Library
or	O
Gstreamer	B-Language
gst-launch-1.0	O
command	O
.	O
</s>
<s>
The	O
command	O
line-programs	O
:	O
</s>
<s>
avconv	B-Language
A	O
video	O
and	O
audio	O
converter	B-Algorithm
that	O
can	O
also	O
grab	O
from	O
a	O
live	O
audio/video	O
source	O
.	O
</s>
<s>
avplay	O
A	O
very	O
simple	O
and	O
portable	O
media	B-Device
player	I-Device
using	O
the	O
Libav	B-Language
libraries	B-Library
and	O
the	O
SDL	B-Operating_System
library	I-Operating_System
.	O
</s>
<s>
The	O
libraries	B-Library
:	O
</s>
<s>
libavcodec	B-Language
A	O
library	O
containing	O
all	O
the	O
Libav	B-Language
audio/video	O
encoders	O
and	O
decoders	O
.	O
</s>
<s>
libavfilter	B-Library
The	O
substitute	O
for	O
vhook	O
which	O
allows	O
the	O
video/audio	O
to	O
be	O
modified	O
or	O
examined	O
between	O
the	O
decoder	O
and	O
the	O
encoder	O
.	O
</s>
<s>
libavformat	B-Library
A	O
library	O
containing	O
demuxers	B-Architecture
and	O
muxers	B-Architecture
for	O
audio	O
and	O
video	O
container	O
formats	O
.	O
</s>
<s>
libavresample	O
A	O
library	O
containing	O
audio	O
resampling	B-Algorithm
routines	O
.	O
</s>
<s>
libavutil	B-Library
A	O
helper	O
library	O
containing	O
routines	O
common	O
to	O
different	O
parts	O
of	O
Libav	B-Language
.	O
</s>
<s>
This	O
library	O
includes	O
Adler-32	B-Algorithm
,	O
CRC	O
,	O
MD5	B-Algorithm
,	O
SHA-1	B-Algorithm
,	O
LZO	B-Language
decompressor	O
,	O
Base64	B-Protocol
encoder/decoder	B-General_Concept
,	O
DES	B-Algorithm
encrypter/decrypter	O
,	O
RC4	B-Algorithm
encrypter/decrypter	O
and	O
AES	B-Algorithm
encrypter/decrypter	O
.	O
</s>
<s>
libswscale	B-Application
A	O
library	O
containing	O
video	O
image	B-Algorithm
scaling	I-Algorithm
and	O
colorspace/pixelformat	O
conversion	O
routines	O
.	O
</s>
<s>
Numerous	O
free	B-License
and	I-License
open-source	I-License
implementations	O
of	O
existing	O
algorithms	O
for	O
the	O
(	O
usually	O
lossy	O
)	O
compression	O
and	O
decompression	O
of	O
audio	O
or	O
video	O
data	O
,	O
called	O
codecs	B-General_Concept
,	O
are	O
available	O
.	O
</s>
<s>
Here	O
are	O
lists	O
of	O
the	O
ones	O
contained	O
in	O
the	O
libav	B-Language
library	O
:	O
</s>
<s>
Libav	B-Language
includes	O
video	O
decoders	O
and/or	O
encoders	O
for	O
the	O
following	O
formats	O
:	O
</s>
<s>
DVD	O
Forum	O
standards	O
related	O
/	O
Dolby	O
audio	O
codecs	B-General_Concept
:	O
MLP	B-Algorithm
(	O
a.k.a.	O
</s>
<s>
Windows	B-Device
Media	I-Device
Player	I-Device
related	O
video	O
codecs	B-General_Concept
:	O
Microsoft	O
RLE	O
,	O
Microsoft	B-Algorithm
Video	I-Algorithm
1	I-Algorithm
,	O
Cinepak	B-Algorithm
,	O
Indeo	B-Algorithm
2	O
,	O
3	O
and	O
5	O
,	O
Motion	B-Application
JPEG	I-Application
,	O
Microsoft	O
MPEG-4	O
v1	O
,	O
v2	O
and	O
v3	O
,	O
WMV1	O
,	O
WMV2	O
and	O
WMV3	B-Device
(	O
a.k.a.	O
</s>
<s>
SMPTE	O
video	O
standards	O
:	O
VC-1	B-Operating_System
(	O
a.k.a.	O
</s>
<s>
WMV3	B-Device
)	O
,	O
VC-2	B-Application
(	O
a.k.a.	O
</s>
<s>
Dirac	B-Application
)	O
,	O
VC-3	O
(	O
a.k.a.	O
</s>
<s>
Libav	B-Language
includes	O
decoders	O
and	O
encoders	O
for	O
the	O
following	O
formats	O
:	O
</s>
<s>
3GPP	O
vocoder	O
standards	O
:	O
AMR-NB	B-Algorithm
,	O
AMR-WB	B-Algorithm
(	O
a.k.a.	O
</s>
<s>
ITU-T	O
vocoder	O
standards	O
:	O
G.711	B-Algorithm
μ-law	O
,	O
G.711	B-Algorithm
A-law	O
,	O
G.721	B-Algorithm
(	O
a.k.a.	O
</s>
<s>
G.726	B-Algorithm
32k	O
)	O
,	O
G.722	B-Algorithm
,	O
G.722.2	B-Algorithm
(	O
a.k.a.	O
</s>
<s>
AMR-WB	B-Algorithm
)	O
,	O
G.723	B-Algorithm
(	O
a.k.a.	O
</s>
<s>
RealPlayer	B-Application
related	O
audio	O
codecs	B-General_Concept
:	O
RealAudio	B-Algorithm
3	O
,	O
6	O
,	O
7	O
,	O
8	O
,	O
9	O
and	O
10	O
(	O
a.k.a.	O
</s>
<s>
Additionally	O
to	O
the	O
aforementioned	O
codecs	B-General_Concept
,	O
Libav	B-Language
also	O
supports	O
several	O
file	O
formats	O
(	O
file	O
formats	O
designed	O
to	O
contain	O
audio	O
and/or	O
video	O
data	O
and	O
subtitles	O
,	O
are	O
called	O
"	O
containers	O
"	O
,	O
but	O
that	O
is	O
just	O
a	O
special	O
denomination	O
.	O
</s>
<s>
Support	O
for	O
several	O
communications	O
protocols	O
is	O
also	O
contained	O
in	O
Libav	B-Language
.	O
</s>
