<s>
Data	B-General_Concept
compression	I-General_Concept
ratio	I-General_Concept
,	O
also	O
known	O
as	O
compression	O
power	O
,	O
is	O
a	O
measurement	O
of	O
the	O
relative	O
reduction	O
in	O
size	O
of	O
data	O
representation	O
produced	O
by	O
a	O
data	O
compression	O
algorithm	O
.	O
</s>
<s>
Data	B-General_Concept
compression	I-General_Concept
ratio	I-General_Concept
is	O
defined	O
as	O
the	O
ratio	O
between	O
the	O
uncompressed	O
size	O
and	O
compressed	O
size	O
:	O
</s>
<s>
For	O
example	O
,	O
uncompressed	O
songs	O
in	O
CD	O
format	O
have	O
a	O
data	O
rate	O
of	O
16	O
bits/channel	O
x	O
2	O
channels	O
x	O
44.1kHz	O
≅	O
1.4	O
Mbit/s	O
,	O
whereas	O
AAC	B-Application
files	I-Application
on	O
an	O
iPod	O
are	O
typically	O
compressed	O
to	O
128	O
kbit/s	O
,	O
yielding	O
a	O
compression	O
ratio	O
of	O
10.9	O
,	O
for	O
a	O
data-rate	O
saving	O
of	O
0.91	O
,	O
or	O
91%	O
.	O
</s>
<s>
Lossless	B-Algorithm
compression	I-Algorithm
of	O
digitized	O
data	O
such	O
as	O
video	O
,	O
digitized	O
film	O
,	O
and	O
audio	O
preserves	O
all	O
the	O
information	O
,	O
but	O
it	O
does	O
not	O
generally	O
achieve	O
compression	O
ratio	O
much	O
better	O
than	O
2:1	O
because	O
of	O
the	O
intrinsic	O
entropy	O
of	O
the	O
data	O
.	O
</s>
<s>
In	O
contrast	O
,	O
lossy	B-Algorithm
compression	I-Algorithm
(	O
e.g.	O
</s>
<s>
JPEG	O
for	O
images	O
,	O
or	O
MP3	B-Application
and	O
Opus	B-Algorithm
for	O
audio	O
)	O
can	O
achieve	O
much	O
higher	O
compression	O
ratios	O
at	O
the	O
cost	O
of	O
a	O
decrease	O
in	O
quality	O
,	O
such	O
as	O
Bluetooth	O
audio	O
streaming	O
,	O
as	O
visual	O
or	O
audio	O
compression	O
artifacts	O
from	O
loss	O
of	O
important	O
information	O
are	O
introduced	O
.	O
</s>
<s>
The	O
data	B-General_Concept
compression	I-General_Concept
ratio	I-General_Concept
can	O
serve	O
as	O
a	O
measure	O
of	O
the	O
complexity	O
of	O
a	O
data	O
set	O
or	O
signal	O
.	O
</s>
