<s>
LV2	B-Application
(	O
LADSPA	B-Language
Version	O
2	O
)	O
is	O
a	O
set	O
of	O
royalty-free	O
open	O
standards	O
for	O
plug-ins	B-Application
and	O
matching	O
host	O
applications	O
.	O
</s>
<s>
It	O
includes	O
support	O
for	O
the	O
synthesis	O
and	O
processing	B-General_Concept
of	O
digital	O
audio	O
and	O
CV	O
,	O
events	O
such	O
as	O
MIDI	O
and	O
OSC	O
,	O
and	O
provides	O
a	O
free	O
alternative	O
to	O
audio	B-Application
plug-in	I-Application
standards	O
such	O
as	O
Virtual	B-Application
Studio	I-Application
Technology	I-Application
(	O
VST	O
)	O
and	O
Audio	B-Operating_System
Units	I-Operating_System
(	O
AU	O
)	O
.	O
</s>
<s>
LV2	B-Application
succeeds	O
the	O
more	O
limited	O
Linux	B-Language
Audio	I-Language
Developer	I-Language
's	I-Language
Simple	I-Language
Plugin	I-Language
API	I-Language
(	O
LADSPA	B-Language
)	O
standard	O
and	O
replaces	O
the	O
Disposable	B-Application
Soft	I-Application
Synth	I-Application
Interface	I-Application
(	O
DSSI	O
)	O
plugin	B-Application
infrastructure	O
(	O
"	O
LADSPA	B-Language
for	O
instruments	O
"	O
)	O
,	O
adding	O
abilities	O
such	O
as	O
MIDI	O
capability	O
,	O
custom	O
UIs	O
,	O
and	O
a	O
system	O
allowing	O
extensibility	O
of	O
the	O
initial	O
standard	O
.	O
</s>
<s>
Over	O
twelve	O
hundred	O
plugins	B-Application
are	O
now	O
available	O
in	O
LV2	B-Application
format	O
.	O
</s>
<s>
Notable	O
plugins	B-Application
include	O
Calf	B-Application
Studio	I-Application
Gear	I-Application
.	O
</s>
<s>
Software	O
that	O
can	O
host	O
LV2	B-Application
plugin	B-Application
"	O
bundles	O
"	O
includes	O
Ardour	B-Language
,	O
,	O
(	O
of	O
KXStudio	O
)	O
,	O
Qtractor	B-Language
,	O
Traverso	B-Language
DAW	I-Language
,	O
Harrison	B-Application
Mixbus	I-Application
,	O
MusE	B-Language
,	O
Audacity	B-Language
,	O
Ecasound	B-Language
,	O
FFmpeg	B-Library
,	O
Guitarix	O
,	O
the	O
GStreamer	B-Language
framework	O
and	O
DJing	O
software	O
Mixxx	B-Language
,	O
with	O
currently	O
partial	O
support	O
in	O
LMMS	B-Language
and	O
REAPER	B-Application
.	O
</s>
<s>
It	O
is	O
also	O
the	O
plugin	B-Application
format	O
used	O
by	O
the	O
MOD	O
Duo	O
and	O
MOD	O
Duo	O
X	O
,	O
,	O
and	O
Digit/Beebo	O
hardware	O
units	O
.	O
</s>
<s>
LV2	B-Application
is	O
an	O
extensible	O
framework	O
,	O
allowing	O
a	O
program	O
to	O
load	O
a	O
plugin	B-Application
to	O
do	O
some	O
processing	B-General_Concept
.	O
</s>
<s>
Note	O
that	O
the	O
terms	O
used	O
here	O
are	O
generic	O
on	O
purpose	O
because	O
LV2	B-Application
allows	O
any	O
type	O
of	O
data	O
to	O
be	O
exchanged	O
between	O
the	O
host	O
and	O
the	O
plugin	B-Application
.	O
</s>
<s>
The	O
LV2	B-Application
specifications	O
are	O
defined	O
by	O
and	O
make	O
use	O
of	O
RDF	O
metadata	O
in	O
Turtle	O
format	O
.	O
</s>
<s>
Technologies	O
involved	O
include	O
Dublin	O
Core	O
,	O
FOAF	O
,	O
DOAP	O
,	O
SPDX	O
,	O
XSD	O
,	O
RDFS	O
and	O
OWL	B-Language
.	O
</s>
<s>
Beyond	O
the	O
core	O
specification	O
there	O
are	O
21	O
official	O
extensions	O
providing	O
support	O
for	O
host	O
options	O
,	O
plugin	B-Application
presets	O
,	O
time	O
and	O
units	O
,	O
port	O
buffers	O
,	O
properties	O
,	O
groups	O
and	O
parameter	O
labels	O
,	O
for	O
sending	O
MIDI	O
,	O
patches	O
,	O
UI	O
events	O
and	O
more	O
.	O
</s>
<s>
The	O
plugin	B-Application
uses	O
this	O
information	O
to	O
provide	O
a	O
list	O
of	O
capabilities	O
to	O
the	O
host	O
,	O
so	O
the	O
host	O
can	O
accommodate	O
those	O
.	O
</s>
<s>
Similarly	O
,	O
the	O
host	O
can	O
provide	O
a	O
list	O
of	O
LV2	B-Application
extension	O
capabilities	O
that	O
it	O
supports	O
on	O
initialization	O
of	O
the	O
plugin	B-Application
.	O
</s>
<s>
In	O
the	O
example	O
below	O
,	O
first	O
the	O
shortcut	O
prefixes	O
for	O
the	O
lv2	B-Application
,	O
doap	O
and	O
spdx	O
ontology	O
are	O
declared	O
.	O
</s>
<s>
Next	O
,	O
every	O
plugin	B-Application
must	O
have	O
its	O
own	O
URI	B-Protocol
or	O
URN	B-Protocol
.	O
</s>
<s>
Then	O
the	O
4	O
following	O
lines	O
declare	O
that	O
this	O
resource	O
is	O
an	O
lv2:Plugin	O
,	O
a	O
binary	O
object	B-Application
file	I-Application
library	O
with	O
the	O
filename	O
silence.so	O
should	O
be	O
present	O
,	O
that	O
the	O
plugin	B-Application
is	O
known	O
under	O
the	O
name	O
Silence	O
,	O
and	O
is	O
licensed	O
under	O
the	O
GNU	O
GPL	O
.	O
</s>
<s>
These	O
4	O
properties	O
are	O
mandatory	O
for	O
an	O
LV2	B-Application
plugin	B-Application
;	O
if	O
a	O
plugin	B-Application
does	O
not	O
have	O
all	O
of	O
them	O
a	O
host	O
might	O
not	O
load	O
it	O
.	O
</s>
<s>
"	O
Atom	O
"	O
data	B-General_Concept
structures	I-General_Concept
are	O
used	O
for	O
messaging	O
between	O
plugin	B-Application
ports	O
for	O
the	O
transfer	O
of	O
MIDI	O
,	O
OSC	O
,	O
Patch	O
,	O
UI	O
and	O
other	O
events	O
between	O
plugin	B-Application
instances	O
.	O
</s>
<s>
Aside	O
from	O
separating	O
metadata	O
from	O
binaries	O
,	O
LV2	B-Application
mandates	O
a	O
general	O
separation	O
between	O
DSP	O
and	O
user	O
interface	O
processing	B-General_Concept
.	O
</s>
<s>
Benefits	O
include	O
that	O
UI	O
processing	B-General_Concept
cannot	O
hold	O
back	O
DSP	O
processing	B-General_Concept
,	O
and	O
UI	O
and	O
DSP	O
can	O
be	O
separated	O
across	O
a	O
network	O
.	O
</s>
<s>
Hosts	O
can	O
also	O
provide	O
an	O
interface	O
for	O
displaying	O
and	O
configuring	O
the	O
properties	O
of	O
plugin	B-Application
instances	O
.	O
</s>
<s>
One	O
capability	O
that	O
a	O
host	O
can	O
provide	O
to	O
a	O
plugin	B-Application
is	O
a	O
"	O
worker	O
thread	O
"	O
.	O
</s>
<s>
In	O
programming	O
terms	O
,	O
this	O
means	O
that	O
the	O
plugin	B-Application
can	O
offload	O
some	O
work	O
to	O
be	O
done	O
in	O
another	O
thread	O
that	O
the	O
host	O
provides	O
.	O
</s>
<s>
This	O
is	O
generally	O
useful	O
because	O
a	O
plugin	B-Application
is	O
usually	O
run	O
in	O
the	O
real-time	O
audio	O
thread	O
of	O
an	O
application	O
,	O
and	O
hence	O
cannot	O
do	O
any	O
non-real-time	O
safe	O
operations	O
(	O
disk-accesses	O
,	O
system	O
calls	O
,	O
etc	O
.	O
)	O
.	O
</s>
<s>
To	O
make	O
it	O
easy	O
for	O
the	O
plugin	B-Application
to	O
achieve	O
its	O
goals	O
(	O
e.g.	O
</s>
<s>
The	O
host	O
provides	O
the	O
LV2_Extension	O
for	O
the	O
worker	O
thread	O
and	O
the	O
plugin	B-Application
is	O
then	O
able	O
to	O
use	O
it	O
.	O
</s>
<s>
There	O
are	O
tools	O
and	O
frameworks	O
available	O
to	O
assist	O
with	O
in	O
creating	O
LV2	B-Application
plugins	B-Application
.	O
</s>
<s>
These	O
include	O
DPF	O
(	O
DISTRHO	O
Plugin	B-Application
Framework	O
)	O
,	O
JUCE	B-Language
,	O
Faust	B-Language
,	O
Dplug	O
,	O
iPlug	O
2	O
(	O
alpha	O
)	O
,	O
and	O
Cabbage	O
(	O
alpha	O
)	O
.	O
</s>
<s>
There	O
is	O
also	O
the	O
ability	O
to	O
load	O
Pure	B-Language
Data	I-Language
patches	O
as	O
well	O
as	O
JIT-run	O
Faust	B-Language
,	O
Rust	O
,	O
Lua	O
or	O
C	B-Language
code	O
in	O
certain	O
LV2	B-Application
plugins	B-Application
.	O
</s>
