<s>
Context-adaptive	B-Algorithm
variable-length	I-Algorithm
coding	I-Algorithm
(	O
CAVLC	B-Algorithm
)	O
is	O
a	O
form	O
of	O
entropy	B-Algorithm
coding	I-Algorithm
used	O
in	O
H.264/MPEG	B-Application
-4	I-Application
AVC	I-Application
video	O
encoding	O
.	O
</s>
<s>
It	O
is	O
an	O
inherently	O
lossless	B-Algorithm
compression	I-Algorithm
technique	O
,	O
like	O
almost	O
all	O
entropy-coders	O
.	O
</s>
<s>
In	O
H.264/MPEG	B-Application
-4	I-Application
AVC	I-Application
,	O
it	O
is	O
used	O
to	O
encode	O
residual	O
,	O
zig-zag	O
order	O
,	O
blocks	O
of	O
transform	O
coefficients	O
.	O
</s>
<s>
It	O
is	O
an	O
alternative	O
to	O
context-based	O
adaptive	O
binary	O
arithmetic	B-Algorithm
coding	I-Algorithm
(	O
CABAC	O
)	O
.	O
</s>
<s>
CAVLC	B-Algorithm
requires	O
considerably	O
less	O
processing	O
to	O
decode	O
than	O
CABAC	O
,	O
although	O
it	O
does	O
not	O
compress	O
the	O
data	O
quite	O
as	O
effectively	O
.	O
</s>
<s>
CAVLC	B-Algorithm
is	O
supported	O
in	O
all	O
H.264	B-Application
profiles	O
,	O
unlike	O
CABAC	O
which	O
is	O
not	O
supported	O
in	O
Baseline	O
and	O
Extended	O
profiles	O
.	O
</s>
<s>
CAVLC	B-Algorithm
is	O
used	O
to	O
encode	O
residual	O
,	O
zig-zag	O
ordered	O
4×4	O
(	O
and	O
2×2	O
)	O
blocks	O
of	O
transform	O
coefficients	O
.	O
</s>
<s>
CAVLC	B-Algorithm
is	O
designed	O
to	O
take	O
advantage	O
of	O
several	O
characteristics	O
of	O
quantized	O
4×4	O
blocks	O
:	O
</s>
<s>
CAVLC	B-Algorithm
signals	O
the	O
number	O
of	O
high-frequency	O
+	O
/	O
−1	O
coefficients	O
in	O
a	O
compact	O
way	O
.	O
</s>
<s>
CAVLC	B-Algorithm
takes	O
advantage	O
of	O
this	O
by	O
adapting	O
the	O
choice	O
of	O
VLC	O
look-up	O
table	O
for	O
the	O
“	O
level	O
”	O
parameter	O
depending	O
on	O
recently	O
coded	O
level	O
magnitudes	O
.	O
</s>
