<s>
Music	B-Application
information	I-Application
retrieval	I-Application
(	O
MIR	O
)	O
is	O
the	O
interdisciplinary	O
science	O
of	O
retrieving	O
information	O
from	O
music	O
.	O
</s>
<s>
Those	O
involved	O
in	O
MIR	O
may	O
have	O
a	O
background	O
in	O
academic	O
musicology	O
,	O
psychoacoustics	O
,	O
psychology	O
,	O
signal	O
processing	O
,	O
informatics	O
,	O
machine	O
learning	O
,	O
optical	B-Application
music	I-Application
recognition	I-Application
,	O
computational	B-General_Concept
intelligence	I-General_Concept
or	O
some	O
combination	O
of	O
these	O
.	O
</s>
<s>
One	O
of	O
the	O
classical	O
MIR	O
research	O
topic	O
is	O
genre	O
classification	O
,	O
which	O
is	O
categorizing	O
music	O
items	O
into	O
one	O
of	O
pre-defined	O
genres	O
such	O
as	O
classical	O
,	O
jazz	B-Device
,	O
rock	O
,	O
etc	O
.	O
</s>
<s>
Several	O
recommender	B-Application
systems	I-Application
for	O
music	O
already	O
exist	O
,	O
but	O
surprisingly	O
few	O
are	O
based	O
upon	O
MIR	O
techniques	O
,	O
instead	O
making	O
use	O
of	O
similarity	O
between	O
users	O
or	O
laborious	O
data	O
compilation	O
.	O
</s>
<s>
Pandora	B-Application
,	O
for	O
example	O
,	O
uses	O
experts	O
to	O
tag	O
the	O
music	O
with	O
particular	O
qualities	O
such	O
as	O
"	O
female	O
singer	O
"	O
or	O
"	O
strong	O
bassline	O
"	O
.	O
</s>
<s>
Digital	O
audio	O
formats	O
such	O
as	O
WAV	O
,	O
mp3	B-Application
,	O
and	O
ogg	O
are	O
used	O
when	O
the	O
audio	O
itself	O
is	O
part	O
of	O
the	O
analysis	O
.	O
</s>
<s>
Lossy	O
formats	O
such	O
as	O
mp3	B-Application
and	O
ogg	O
work	O
well	O
with	O
the	O
human	O
ear	O
but	O
may	O
be	O
missing	O
crucial	O
data	O
for	O
study	O
.	O
</s>
<s>
Despite	O
this	O
the	O
ubiquity	O
of	O
the	O
mp3	B-Application
has	O
meant	O
much	O
research	O
in	O
the	O
field	O
involves	O
these	O
as	O
the	O
source	O
material	O
.	O
</s>
<s>
Increasingly	O
,	O
metadata	O
mined	O
from	O
the	O
web	O
is	O
incorporated	O
in	O
MIR	O
for	O
a	O
more	O
rounded	O
understanding	O
of	O
the	O
music	O
within	O
its	O
cultural	O
context	O
,	O
and	O
this	O
recently	O
consists	O
of	O
analysis	O
of	O
social	B-General_Concept
tags	I-General_Concept
for	O
music	O
.	O
</s>
<s>
Analysis	O
can	O
often	O
require	O
some	O
summarising	O
,	O
and	O
for	O
music	O
(	O
as	O
with	O
many	O
other	O
forms	O
of	O
data	O
)	O
this	O
is	O
achieved	O
by	O
feature	B-Algorithm
extraction	I-Algorithm
,	O
especially	O
when	O
the	O
audio	B-General_Concept
content	I-General_Concept
itself	O
is	O
analysed	O
and	O
machine	O
learning	O
is	O
to	O
be	O
applied	O
.	O
</s>
<s>
One	O
common	O
feature	O
extracted	O
is	O
the	O
Mel-Frequency	B-Algorithm
Cepstral	I-Algorithm
Coefficient	I-Algorithm
(	O
MFCC	O
)	O
which	O
is	O
a	O
measure	O
of	O
the	O
timbre	O
of	O
a	O
piece	O
of	O
music	O
.	O
</s>
<s>
Other	O
features	O
may	O
be	O
employed	O
to	O
represent	O
the	O
key	O
,	O
chords	O
,	O
harmonies	B-Library
,	O
melody	O
,	O
main	O
pitch	O
,	O
beats	O
per	O
minute	O
or	O
rhythm	O
in	O
the	O
piece	O
.	O
</s>
<s>
Music	O
analysis	O
and	O
knowledge	O
representation	O
—	O
automatic	B-Application
summarization	I-Application
,	O
citing	O
,	O
excerpting	O
,	O
downgrading	O
,	O
transformation	O
,	O
formal	O
models	O
of	O
music	O
,	O
digital	O
scores	O
and	O
representations	O
,	O
music	O
indexing	O
and	O
metadata	O
.	O
</s>
<s>
is	O
the	O
top-tier	O
venue	O
for	O
music	B-Application
information	I-Application
retrieval	I-Application
research	O
.	O
</s>
