<s>
Variance	B-Algorithm
Adaptive	I-Algorithm
Quantization	I-Algorithm
(	O
VAQ	B-Algorithm
)	O
is	O
a	O
video	O
encoding	O
algorithm	O
that	O
was	O
first	O
introduced	O
in	O
the	O
open	O
source	O
video	O
encoder	O
x264	B-Language
.	O
</s>
<s>
According	O
to	O
Xvid	B-Algorithm
Builds	O
FAQ	O
:	O
"	O
It	O
's	O
an	O
algorithm	O
that	O
tries	O
to	O
optimally	O
choose	O
a	O
quantizer	B-Algorithm
for	O
each	O
macroblock	B-General_Concept
using	O
advanced	O
math	O
algorithms.	O
"	O
</s>
<s>
It	O
was	O
later	O
ported	O
to	O
programs	O
which	O
encode	O
video	O
content	O
in	O
other	O
video	O
standards	O
,	O
like	O
MPEG-4	B-Application
ASP	I-Application
or	O
MPEG-2	B-Algorithm
.	O
</s>
<s>
In	O
the	O
case	O
of	O
Xvid	B-Algorithm
,	O
the	O
algorithm	O
is	O
intended	O
to	O
make	O
up	O
for	O
the	O
earlier	O
limitations	O
in	O
its	O
Adaptive	B-Algorithm
Quantization	I-Algorithm
mode	O
.	O
</s>
<s>
The	O
first	O
Xvid	B-Algorithm
library	O
containing	O
this	O
improvement	O
was	O
released	O
in	O
February	O
2008	O
.	O
</s>
