<s>
Constant	B-General_Concept
bitrate	I-General_Concept
(	O
CBR	O
)	O
is	O
a	O
term	O
used	O
in	O
telecommunications	O
,	O
relating	O
to	O
the	O
quality	O
of	O
service	O
.	O
</s>
<s>
Compare	O
with	O
variable	B-General_Concept
bitrate	I-General_Concept
.	O
</s>
<s>
When	O
referring	O
to	O
codecs	B-General_Concept
,	O
constant	B-General_Concept
bit	I-General_Concept
rate	I-General_Concept
encoding	B-Algorithm
means	O
that	O
the	O
rate	O
at	O
which	O
a	O
codec	B-General_Concept
's	O
output	O
data	O
should	O
be	O
consumed	O
is	O
constant	O
.	O
</s>
<s>
CBR	O
is	O
useful	O
for	O
streaming	B-Architecture
multimedia	O
content	O
on	O
limited	O
capacity	O
channels	O
since	O
it	O
is	O
the	O
maximum	O
bit	O
rate	O
that	O
matters	O
,	O
not	O
the	O
average	O
,	O
so	O
CBR	O
would	O
be	O
used	O
to	O
take	O
advantage	O
of	O
all	O
of	O
the	O
capacity	O
.	O
</s>
<s>
The	O
problem	O
of	O
not	O
allocating	O
enough	O
data	O
for	O
complex	O
sections	O
could	O
be	O
solved	O
by	O
choosing	O
a	O
high	O
bitrate	O
to	O
ensure	O
that	O
there	O
will	O
be	O
enough	O
bits	O
for	O
the	O
entire	O
encoding	B-Algorithm
process	O
,	O
though	O
the	O
size	O
of	O
the	O
file	O
at	O
the	O
end	O
would	O
be	O
proportionally	O
larger	O
.	O
</s>
<s>
Most	O
coding	O
schemes	O
such	O
as	O
Huffman	B-General_Concept
coding	I-General_Concept
or	O
run-length	B-Algorithm
encoding	I-Algorithm
produce	O
variable-length	O
codes	O
,	O
making	O
perfect	O
CBR	O
difficult	O
to	O
achieve	O
.	O
</s>
<s>
In	O
the	O
case	O
of	O
streaming	B-Application
video	I-Application
as	O
a	O
CBR	O
,	O
the	O
source	O
could	O
be	O
under	O
the	O
CBR	O
data	O
rate	O
target	O
.	O
</s>
<s>
So	O
in	O
order	O
to	O
complete	O
the	O
stream	O
,	O
it	O
's	O
necessary	O
to	O
add	O
stuffing	B-Protocol
packets	I-Protocol
in	O
the	O
stream	O
to	O
reach	O
the	O
data	O
rate	O
wanted	O
.	O
</s>
