<s>
AviSynth	B-Application
is	O
a	O
frameserver	B-Application
program	O
for	O
Microsoft	B-Application
Windows	I-Application
,	O
Linux	B-Application
and	O
macOS	B-Operating_System
initially	O
developed	O
by	O
Ben	O
Rudiak-Gould	O
,	O
Edwin	O
van	O
Eggelen	O
,	O
Klaus	O
Post	O
,	O
Richard	O
Berg	O
and	O
Ian	O
Brabham	O
in	O
May	O
2000	O
and	O
later	O
picked	O
up	O
and	O
maintained	O
by	O
the	O
open	O
source	O
community	O
which	O
is	O
still	O
active	O
nowadays	O
.	O
</s>
<s>
It	O
is	O
free	B-Application
software	I-Application
under	O
GNU	B-License
GPL	I-License
license	I-License
.	O
</s>
<s>
AviSynth	B-Application
acts	O
as	O
a	O
non-linear	O
video	O
editor	O
controlled	O
entirely	O
by	O
scripting	B-Language
(	O
without	O
a	O
GUI	B-Application
)	O
.	O
</s>
<s>
It	O
emulates	O
an	O
AVI	O
video	O
file	O
(	O
or	O
WAV	O
audio	O
file	O
)	O
as	O
seen	O
by	O
the	O
VFW	B-Device
downstream	O
application	O
,	O
which	O
is	O
typically	O
a	O
media	B-Device
player	I-Device
,	O
video	O
editing	O
software	O
,	O
or	O
an	O
encoder	B-General_Concept
.	O
</s>
<s>
AviSynth	B-Application
is	O
built	O
upon	O
filters	O
,	O
which	O
are	O
much	O
like	O
DirectShow	O
filters	O
,	O
but	O
with	O
a	O
different	O
binary	O
interface	O
.	O
</s>
<s>
AviSynth	B-Application
also	O
performs	O
traditional	O
video	O
editing	O
tasks	O
like	O
cutting	O
,	O
trimming	O
and	O
re-sequencing	O
segments	O
.	O
</s>
<s>
This	O
script	O
file	O
can	O
be	O
opened	O
in	O
most	O
media	B-Device
players	I-Device
(	O
such	O
as	O
Windows	B-Device
Media	I-Device
Player	I-Device
)	O
.	O
</s>
<s>
The	O
program	O
will	O
play	O
the	O
video	O
file	O
"	O
myAvi.avi	O
"	O
cropped	O
down	O
to	O
its	O
top-left	O
320	O
pixels	B-Algorithm
by	O
240	O
pixels	B-Algorithm
and	O
blurred	O
by	O
a	O
small	O
amount	O
.	O
</s>
<s>
Technically	O
,	O
AviSynth	B-Application
constructs	O
a	O
filter	B-Library
graph	I-Library
(	O
like	O
Microsoft	O
GraphEdit	B-Application
but	O
with	O
added	O
capabilities	O
)	O
,	O
controlled	O
by	O
scripts	O
written	O
in	O
the	O
.	O
</s>
<s>
Its	O
functionality	O
can	O
be	O
extended	O
through	O
the	O
use	O
of	O
third-party	O
filters	O
known	O
as	O
plugins	B-Application
.	O
</s>
<s>
An	O
external	O
plugin	B-Application
list	O
is	O
maintained	O
at	O
.	O
</s>
<s>
AviSynth	B-Application
is	O
a	O
frameserver	B-Application
the	O
calling	O
program	O
requests	O
audio/video	O
frames	O
and	O
the	O
script	O
serves	O
them	O
.	O
</s>
<s>
The	O
scripting	B-Language
language	I-Language
is	O
a	O
dataflow	O
language	O
:	O
a	O
programming	O
paradigm	O
that	O
describes	O
a	O
directed	O
graph	O
of	O
the	O
data	O
flowing	O
between	O
operations	O
.	O
</s>
<s>
It	O
lacks	O
some	O
procedural	B-Application
programming	I-Application
control	O
structures	O
,	O
but	O
it	O
contains	O
many	O
features	O
familiar	O
to	O
programmers	O
,	O
including	O
variables	O
,	O
distinct	O
datatypes	O
,	O
conditionals	O
,	O
and	O
complex	O
expressions	O
.	O
</s>
<s>
The	O
script	O
has	O
a	O
single	O
return	B-Language
value	I-Language
,	O
which	O
is	O
the	O
audio	O
and	O
video	O
'	O
seen	O
 '	O
by	O
the	O
program	O
running	O
the	O
script	O
.	O
</s>
<s>
This	O
is	O
normally	O
the	O
last	O
line	O
of	O
the	O
script	O
,	O
but	O
a	O
return	B-Language
statement	I-Language
may	O
be	O
inserted	O
at	O
any	O
point	O
.	O
</s>
<s>
If	O
the	O
above	O
text	O
is	O
entered	O
into	O
a	O
text	O
file	O
with	O
the	O
.avs	O
extension	O
,	O
it	O
can	O
be	O
opened	O
in	O
Windows	B-Device
Media	I-Device
Player	I-Device
or	O
any	O
of	O
the	O
other	O
programs	O
in	O
the	O
list	O
below	O
,	O
and	O
a	O
video	O
containing	O
the	O
words	O
"	O
Hello	O
,	O
world	O
!	O
"	O
</s>
<s>
Avisynth	B-Application
uses	O
syntactic	O
sugar	O
that	O
makes	O
simple	O
scripts	O
far	O
easier	O
to	O
write	O
:	O
an	O
implicit	O
variable	O
called	O
.	O
</s>
<s>
AviSynth	B-Application
filters	O
work	O
in	O
many	O
RGB	O
and	O
YUV	O
color	B-Algorithm
spaces	I-Algorithm
to	O
allow	O
all	O
kinds	O
of	O
video	O
input	O
and	O
output	O
.	O
</s>
<s>
Certain	O
functions	O
only	O
work	O
on	O
specific	O
color	B-Algorithm
spaces	I-Algorithm
,	O
requiring	O
conversion	O
for	O
example	O
,	O
most	O
videos	O
are	O
distributed	O
in	O
a	O
YUV	O
color	B-Algorithm
space	I-Algorithm
,	O
but	O
most	O
color	O
correction	O
is	O
done	O
in	O
one	O
of	O
the	O
RGB	O
spaces	O
.	O
</s>
<s>
The	O
AviSynth	B-Application
scripting	B-Language
language	I-Language
allows	O
for	O
users	O
to	O
define	O
their	O
own	O
functions	O
.	O
</s>
<s>
AviSynth	B-Application
3.0	O
was	O
a	O
complete	O
rewrite	O
of	O
AviSynth	B-Application
2.x	O
,	O
and	O
aimed	O
to	O
overcome	O
the	O
limitations	O
of	O
AviSynth	B-Application
2.x	O
.	O
</s>
<s>
Adding	O
improvements	O
such	O
as	O
an	O
abstracted	O
color	B-Algorithm
space	I-Algorithm
model	O
,	O
in	O
which	O
new	O
color	B-Algorithm
spaces	I-Algorithm
(	O
including	O
two	O
with	O
45-bit	O
depth	O
)	O
could	O
be	O
supported	O
through	O
a	O
plug-in	B-Application
mechanism	O
,	O
better	O
cache	O
management	O
for	O
better	O
performance	O
,	O
and	O
using	O
Ruby	B-Language
rather	O
than	O
the	O
homegrown	O
language	O
employed	O
in	O
current	O
versions	O
.	O
</s>
<s>
AviSynth	B-Application
3.0	O
was	O
to	O
be	O
available	O
for	O
other	O
operating	O
systems	O
than	O
Windows	B-Application
,	O
instead	O
relying	O
on	O
GStreamer	B-Language
,	O
extending	O
support	O
to	O
platforms	O
such	O
as	O
Linux	B-Application
,	O
Mac	B-Operating_System
OS	I-Operating_System
X	I-Operating_System
and	O
BSD	B-Operating_System
.	O
</s>
<s>
The	O
most	O
current	O
and	O
modern	O
version	O
of	O
AviSynth	B-Application
today	O
is	O
,	O
originally	O
a	O
fork	O
of	O
the	O
official	O
AviSynth	B-Application
2.xx	O
,	O
but	O
AviSynth+	O
has	O
since	O
gained	O
widespread	O
recognition	O
and	O
has	O
become	O
the	O
go-to	O
implementation	O
.	O
</s>
<s>
It	O
rewrote	O
most	O
of	O
the	O
original	O
AviSynth	B-Application
code	O
,	O
and	O
introduced	O
long-sought	O
features	O
such	O
as	O
64-bit	O
support	O
,	O
multithreading	O
,	O
deep	O
color	B-Algorithm
spaces	I-Algorithm
,	O
support	O
for	O
recent	O
compilers	O
,	O
new	O
scripting	B-Language
constructs	O
(	O
new	O
control-flow	O
constructs	O
such	O
as	O
loops	O
)	O
,	O
and	O
increased	O
performance	O
in	O
many	O
areas	O
.	O
</s>
<s>
At	O
the	O
same	O
time	O
it	O
retained	O
100%	O
compatibility	O
to	O
the	O
AviSynth	B-Application
2.5/2.6	O
series	O
,	O
both	O
for	O
filters	O
and	O
host	O
applications	O
.	O
</s>
<s>
AviSynth	B-Application
2.xx	O
may	O
be	O
used	O
under	O
operating	O
systems	O
other	O
than	O
Windows	B-Application
through	O
the	O
use	O
of	O
Wine	B-Application
.	O
</s>
<s>
To	O
work	O
on	O
scripts	O
VirtualDub/VirtualDubMod	O
can	O
be	O
used	O
as	O
on	O
Windows	B-Application
.	O
</s>
<s>
To	O
interface	O
between	O
AviSynth	B-Application
under	O
Wine	B-Application
and	O
for	O
example	O
FFmpeg	B-Library
running	O
on	O
a	O
Linux	B-Application
host	O
,	O
Avs2YUV	O
can	O
be	O
used	O
.	O
</s>
<s>
Avs2YUV	O
is	O
a	O
Windows	B-Application
command	O
line	O
program	O
that	O
is	O
run	O
under	O
Wine	B-Application
and	O
renders	O
the	O
output	O
of	O
an	O
AviSynth	B-Application
script	O
to	O
stdout	B-Operating_System
that	O
is	O
then	O
piped	O
to	O
FFmpeg	B-Library
.	O
</s>
<s>
Avs2YUV	O
also	O
supports	O
writing	O
to	O
a	O
named	B-Operating_System
pipe	I-Operating_System
.	O
</s>
<s>
There	O
is	O
a	O
Linux	B-Application
port	O
of	O
AviSynth	B-Application
called	O
AvxSynth	O
.	O
</s>
<s>
Program	O
name	O
License	O
Comments	O
Homepage	O
Adobe	B-Operating_System
Premiere	I-Operating_System
Pro	I-Operating_System
Proprietary	O
,	O
commercial	O
Versions	O
6.0	O
and	O
later	O
(	O
up	O
to	O
and	O
including	O
CS4	O
)	O
have	O
an	O
AviSynth	B-Application
import	O
plugin	B-Application
available	O
.	O
</s>
<s>
Premiere	O
AviSynth	B-Application
import	O
plugin	B-Application
Avanti	O
GUI	B-Application
Proprietary	O
,	O
freeware	B-License
Avanti	O
GUI	B-Application
is	O
a	O
free	O
front-end	O
for	O
FFmpeg	B-Library
with	O
the	O
option	O
to	O
insert	O
AviSynth	B-Application
as	O
pre-processor	O
.	O
</s>
<s>
Avanti	O
GUI	B-Application
AvsPmod	O
GPL	B-License
AvsPmod	O
is	O
AviSynth	B-Application
script	O
editor	O
with	O
builtin	O
player	O
,	O
syntax	O
highlighting	O
and	O
code	O
autocompletion	O
.	O
</s>
<s>
AvsPmod	O
Cinema	O
Craft	O
Encoder	B-General_Concept
Proprietary	O
Cinema	O
Craft	O
Encoder	B-General_Concept
is	O
a	O
commercial	O
MPEG-2	O
encoder	B-General_Concept
that	O
supports	O
AviSynth	B-Application
input	O
.	O
</s>
<s>
Cinema	O
Craft	O
FFmpeg	B-Library
LGPL2.1	O
+	O
,	O
GPL	B-License
2+	O
FFmpeg	B-Library
compiled	O
for	O
windows	B-Application
can	O
receive	O
AviSynth	B-Application
input	O
instructions	O
GOM	B-Application
Player	I-Application
Proprietary	O
,	O
freeware	B-License
,	O
ad-supported	O
can	O
play	O
.avs	O
files	O
Media	B-Language
Player	I-Language
Classic	I-Language
GPL	B-License
Media	B-Language
Player	I-Language
Classic	I-Language
is	O
capable	O
of	O
loading	O
and	O
playing	O
AviSynth	B-Application
scripts	O
.	O
</s>
<s>
Media	B-Language
Player	I-Language
Classic	I-Language
Microsoft	B-Application
Expression	I-Application
Encoder	I-Application
Proprietary	O
,	O
freemium	O
Microsoft	B-Application
Expression	I-Application
Encoder	I-Application
can	O
import	O
and	O
transcode	O
.avs	O
files	O
.	O
</s>
<s>
MPlayer	B-Application
GPL	B-License
MPlayer	B-Application
can	O
play	O
.avs	O
files	O
Nero	B-Application
Multimedia	I-Application
Suite	I-Application
Proprietary	O
,	O
commercial	O
Nero	B-Application
Showtime	I-Application
can	O
play	O
avs	O
files	O
SUPER	B-Application
Proprietary	O
,	O
freeware	B-License
,	O
ad-supported	O
SUPER	B-Application
(	O
Simplified	O
Universal	O
Player	O
,	O
Encoder	B-General_Concept
and	O
Renderer	O
)	O
is	O
freeware	B-License
from	O
eRightSoft	O
that	O
can	O
encode	O
most	O
common	O
video	O
formats	O
and	O
has	O
full	O
AviSynth	B-Application
support	O
.	O
</s>
<s>
SUPER	B-Application
TMPGEnc	B-Application
Shareware/freeware	O
TMPGEnc	B-Application
is	O
a	O
free	O
MPEG-1	O
and	O
MPEG-2	O
encoder	B-General_Concept
.	O
</s>
<s>
TMPGEnc	B-Application
Plus	O
and	O
TMPGEnc	B-Application
Express	O
are	O
commercial	O
versions	O
of	O
TMPGEnc	B-Application
that	O
include	O
enhanced	O
functionality	O
,	O
as	O
well	O
as	O
the	O
removal	O
of	O
a	O
30-day	O
restriction	O
on	O
MPEG-2	O
encoding	O
present	O
in	O
TMPGEnc	B-Application
.	O
</s>
<s>
Pegasys	O
Inc	O
.	O
Total	O
video	O
converter	O
Proprietary	O
,	O
trialware	O
Total	O
video	O
converter	O
has	O
an	O
AviSynth	B-Application
import	O
plugin	B-Application
available	O
.	O
</s>
<s>
Total	O
Video	O
Converter	O
VirtualDub	B-Application
GPL	B-License
VirtualDub	B-Application
is	O
a	O
widely	O
used	O
all-purpose	O
video	O
converter	O
.	O
</s>
<s>
VirtualDub	B-Application
VirtualDubMod	B-Language
GPL	B-License
VirtualDubMod	B-Language
contains	O
several	O
AviSynth-specific	O
features	O
such	O
as	O
explicit	O
support	O
for	O
AviSynth	B-Application
scripts	O
,	O
an	O
AviSynth	B-Application
script	O
editor	O
,	O
and	O
more	O
.	O
</s>
<s>
VirtualDubMod	B-Language
Windows	B-Device
Media	I-Device
Player	I-Device
Proprietary	O
,	O
component	O
of	O
Windows	B-Application
/	O
freeware	B-License
Windows	B-Device
Media	I-Device
Player	I-Device
is	O
capable	O
of	O
loading	O
and	O
playing	O
AviSynth	B-Application
scripts	O
,	O
so	O
it	O
is	O
a	O
good	O
choice	O
for	O
simple	O
playback	O
and	O
testing	O
.	O
</s>
<s>
In	O
addition	O
,	O
several	O
programs	O
have	O
now	O
been	O
created	O
which	O
accept	O
only	O
AviSynth	B-Application
scripts	O
as	O
input	O
-	O
thereby	O
simplifying	O
the	O
programs	O
themselves	O
but	O
giving	O
users	O
the	O
full	O
power	O
of	O
AviSynth	B-Application
for	O
input	O
.	O
</s>
<s>
There	O
are	O
also	O
several	O
batch	O
encoding	O
applications	O
that	O
tie	O
together	O
AviSynth	B-Application
with	O
command	O
line	O
audio	O
and	O
video	O
encoders	O
and	O
muxers	O
to	O
provide	O
an	O
all-in-one	O
,	O
modular	O
,	O
customizable	O
video	O
encoding	O
application	O
.	O
</s>
<s>
Although	O
AviSynth	B-Application
scripts	O
are	O
meant	O
to	O
be	O
easily	O
opened	O
in	O
simple	O
text	O
editing	O
programs	O
,	O
there	O
are	O
several	O
editors	O
meant	O
especially	O
for	O
editing	O
AviSynth	B-Application
scripts	O
such	O
as	O
.	O
</s>
