<s>
Opus	B-Algorithm
is	O
a	O
lossy	B-Algorithm
audio	O
coding	O
format	O
developed	O
by	O
the	O
Xiph.Org	B-Application
Foundation	I-Application
and	O
standardized	O
by	O
the	O
Internet	O
Engineering	O
Task	O
Force	O
,	O
designed	O
to	O
efficiently	O
code	B-Application
speech	I-Application
and	O
general	O
audio	O
in	O
a	O
single	O
format	O
,	O
while	O
remaining	O
low-latency	O
enough	O
for	O
real-time	O
interactive	O
communication	O
and	O
low-complexity	O
enough	O
for	O
low-end	O
embedded	O
processors	O
.	O
</s>
<s>
Opus	B-Algorithm
replaces	O
both	O
Vorbis	B-Algorithm
and	O
Speex	B-Application
for	O
new	O
applications	O
,	O
and	O
several	O
blind	O
listening	O
tests	O
have	O
ranked	O
it	O
higher-quality	O
than	O
any	O
other	O
standard	O
audio	O
format	O
at	O
any	O
given	O
bitrate	O
until	O
transparency	B-Algorithm
is	O
reached	O
,	O
including	O
MP3	B-Application
,	O
AAC	B-Application
,	O
and	O
HE-AAC	O
.	O
</s>
<s>
Opus	B-Algorithm
combines	O
the	O
speech-oriented	O
LPC-based	O
SILK	O
algorithm	O
and	O
the	O
lower-latency	O
MDCT-based	O
CELT	B-Algorithm
algorithm	O
,	O
switching	O
between	O
or	O
combining	O
them	O
as	O
needed	O
for	O
maximal	O
efficiency	O
.	O
</s>
<s>
Opus	B-Algorithm
has	O
the	O
low	O
algorithmic	O
delay	O
(	O
26.5ms	O
by	O
default	O
)	O
necessary	O
for	O
use	O
as	O
part	O
of	O
a	O
real-time	O
communication	O
link	O
,	O
networked	B-Protocol
music	I-Protocol
performances	I-Protocol
,	O
and	O
live	O
lip	O
sync	O
;	O
by	O
trading-off	O
quality	O
or	O
bitrate	O
,	O
the	O
delay	O
can	O
be	O
reduced	O
down	O
to	O
5ms	O
.	O
</s>
<s>
Its	O
delay	O
is	O
exceptionally	O
low	O
compared	O
to	O
competing	O
codecs	O
,	O
which	O
require	O
well	O
over	O
100ms	O
,	O
yet	O
Opus	B-Algorithm
performs	O
very	O
competitively	O
with	O
these	O
formats	O
in	O
terms	O
of	O
quality	O
per	O
bitrate	O
.	O
</s>
<s>
As	O
an	O
open	O
format	O
standardized	O
through	O
RFC	B-Algorithm
6716	I-Algorithm
,	O
a	O
reference	O
implementation	O
called	O
libopus	B-Algorithm
is	O
available	O
under	O
the	O
New	O
BSD	B-Operating_System
License	I-Operating_System
.	O
</s>
<s>
The	O
reference	O
has	O
both	O
fixed-point	O
and	O
floating-point	B-Algorithm
optimizations	O
for	O
low	O
-	O
and	O
high-end	O
devices	O
,	O
with	O
SIMD	B-Device
optimizations	O
on	O
platforms	O
that	O
support	O
them	O
.	O
</s>
<s>
All	O
known	O
software	O
patents	O
that	O
cover	O
Opus	B-Algorithm
are	O
licensed	O
under	O
royalty-free	O
terms	O
.	O
</s>
<s>
Opus	B-Algorithm
is	O
widely	O
used	O
as	O
the	O
voice	B-Application
over	I-Application
IP	I-Application
(	O
VoIP	B-Application
)	O
codec	O
in	O
applications	O
such	O
as	O
Discord	B-Application
,	O
WhatsApp	B-Application
,	O
and	O
the	B-Operating_System
PlayStation	I-Operating_System
4	I-Operating_System
.	O
</s>
<s>
Opus	B-Algorithm
supports	O
constant	B-General_Concept
and	O
variable	B-General_Concept
bitrate	I-General_Concept
encoding	I-General_Concept
from	O
6kbit/s	O
to	O
510kbit/s	O
(	O
or	O
up	O
to	O
256kbit/s	O
per	O
channel	O
for	O
multi-channel	O
tracks	O
)	O
,	O
frame	O
sizes	O
from	O
2.5ms	O
to	O
60ms	O
,	O
and	O
five	O
sampling	O
rates	O
from	O
8kHz	O
(	O
with	O
4kHz	O
bandwidth	O
)	O
to	O
48kHz	O
(	O
with	O
20kHz	O
bandwidth	O
,	O
the	O
human	O
hearing	O
range	O
)	O
.	O
</s>
<s>
An	O
Opus	B-Algorithm
stream	O
can	O
support	O
up	O
to	O
255	O
audio	O
channels	O
,	O
and	O
it	O
allows	O
channel	O
coupling	O
between	O
channels	O
in	O
groups	O
of	O
two	O
using	O
mid-side	O
coding	O
.	O
</s>
<s>
Opus	B-Algorithm
has	O
very	O
short	O
latency	O
(	O
26.5ms	O
using	O
the	O
default	O
20ms	O
frames	O
and	O
default	O
application	O
setting	O
)	O
,	O
which	O
makes	O
it	O
suitable	O
for	O
real-time	B-General_Concept
applications	I-General_Concept
such	O
as	O
telephony	O
,	O
Voice	B-Application
over	I-Application
IP	I-Application
and	O
videoconferencing	B-Application
;	O
research	O
by	O
Xiph	B-Application
led	O
to	O
the	O
CELT	B-Algorithm
codec	O
,	O
which	O
allows	O
the	O
highest	O
quality	O
while	O
maintaining	O
low	O
delay	O
.	O
</s>
<s>
In	O
any	O
Opus	B-Algorithm
stream	O
,	O
the	O
bitrate	O
,	O
bandwidth	O
,	O
and	O
delay	O
can	O
be	O
continually	O
varied	O
without	O
introducing	O
any	O
distortion	O
or	O
discontinuity	O
;	O
even	O
mixing	O
packets	B-Protocol
from	O
different	O
streams	O
will	O
cause	O
a	O
smooth	O
change	O
,	O
rather	O
than	O
the	O
distortion	O
common	O
in	O
other	O
codecs	O
.	O
</s>
<s>
Unlike	O
Vorbis	B-Algorithm
,	O
Opus	B-Algorithm
does	O
not	O
require	O
large	O
codebooks	O
for	O
each	O
individual	O
file	O
,	O
making	O
it	O
more	O
efficient	O
for	O
short	O
clips	O
of	O
audio	O
and	O
more	O
resilient	O
.	O
</s>
<s>
The	O
Opus	B-Algorithm
format	I-Algorithm
is	O
based	O
on	O
a	O
combination	O
of	O
the	O
full-bandwidth	O
CELT	B-Algorithm
format	O
and	O
the	O
speech-oriented	O
SILK	O
format	O
,	O
both	O
heavily	O
modified	O
:	O
CELT	B-Algorithm
is	O
based	O
on	O
the	O
modified	O
discrete	O
cosine	O
transform	O
(	O
MDCT	O
)	O
that	O
most	O
music	O
codecs	O
use	O
,	O
using	O
CELP	B-Algorithm
techniques	O
in	O
the	O
frequency	O
domain	O
for	O
better	O
prediction	O
,	O
while	O
SILK	O
uses	O
linear	B-Algorithm
predictive	I-Algorithm
coding	I-Algorithm
(	O
LPC	B-Algorithm
)	O
and	O
an	O
optional	O
Long-Term	O
Prediction	O
filter	O
to	O
model	O
speech	O
.	O
</s>
<s>
In	O
Opus	B-Algorithm
,	O
both	O
were	O
modified	O
to	O
support	O
more	O
frame	O
sizes	O
,	O
as	O
well	O
as	O
further	O
algorithmic	O
improvements	O
and	O
integration	O
,	O
such	O
as	O
using	O
CELT	B-Algorithm
's	O
range	B-Algorithm
encoder	I-Algorithm
for	O
both	O
types	O
.	O
</s>
<s>
To	O
minimize	O
overhead	O
at	O
low	O
bitrates	O
,	O
if	O
latency	O
is	O
not	O
as	O
pressing	O
,	O
SILK	O
has	O
support	O
for	O
packing	O
multiple	O
20ms	O
frames	O
together	O
,	O
sharing	O
context	O
and	O
headers	O
;	O
SILK	O
also	O
allows	O
Low	O
Bit-Rate	O
Redundancy	O
(	O
LBRR	O
)	O
frames	O
,	O
allowing	O
low-quality	O
packet	B-Protocol
loss	O
recovery	O
.	O
</s>
<s>
CELT	B-Algorithm
includes	O
both	O
spectral	O
replication	O
and	O
noise	O
generation	O
,	O
similar	O
to	O
AAC	B-Application
's	O
SBR	O
and	O
PNS	O
,	O
and	O
can	O
further	O
save	O
bits	O
by	O
filtering	O
out	O
all	O
harmonics	O
of	O
tonal	O
sounds	O
entirely	O
,	O
then	O
replicating	O
them	O
in	O
the	O
decoder	O
.	O
</s>
<s>
The	O
format	O
has	O
three	O
different	O
modes	O
:	O
speech	O
,	O
hybrid	O
,	O
and	O
CELT	B-Algorithm
.	O
</s>
<s>
If	O
wider	O
bandwidth	O
is	O
desired	O
,	O
a	O
hybrid	O
mode	O
uses	O
CELT	B-Algorithm
to	O
encode	O
the	O
frequency	O
range	O
above	O
8kHz	O
.	O
</s>
<s>
The	O
third	O
mode	O
is	O
pure-CELT	O
,	O
designed	O
for	O
general	O
audio	O
.	O
</s>
<s>
SILK	O
is	O
inherently	O
VBR	B-General_Concept
and	O
cannot	O
hit	O
a	O
bitrate	O
target	O
,	O
while	O
CELT	B-Algorithm
can	O
always	O
be	O
encoded	O
to	O
any	O
specific	O
number	O
of	O
bytes	O
,	O
enabling	O
hybrid	O
and	O
CELT	B-Algorithm
mode	O
when	O
CBR	O
is	O
required	O
.	O
</s>
<s>
CELT	B-Algorithm
supports	O
frame	O
sizes	O
of	O
2.5	O
,	O
5	O
,	O
10	O
and	O
20ms	O
.	O
</s>
<s>
Thus	O
,	O
hybrid	O
mode	O
only	O
supports	O
frame	O
sizes	O
of	O
10	O
and	O
20ms	O
;	O
frames	O
shorter	O
than	O
10ms	O
will	O
always	O
use	O
CELT	B-Algorithm
mode	O
.	O
</s>
<s>
A	O
typical	O
Opus	B-Algorithm
packet	B-Protocol
contains	O
a	O
single	O
frame	O
,	O
but	O
packets	B-Protocol
of	O
up	O
to	O
120ms	O
are	O
produced	O
by	O
combining	O
multiple	O
frames	O
per	O
packet	B-Protocol
.	O
</s>
<s>
Opus	B-Algorithm
can	O
transparently	O
switch	O
between	O
modes	O
,	O
frame	O
sizes	O
,	O
bandwidths	O
,	O
and	O
channel	O
counts	O
on	O
a	O
per-packet	O
basis	O
,	O
although	O
specific	O
applications	O
may	O
choose	O
to	O
limit	O
this	O
.	O
</s>
<s>
The	O
reference	O
implementation	O
is	O
written	O
in	O
C	B-Language
and	O
compiles	O
on	O
hardware	O
architectures	O
with	O
or	O
without	O
a	O
floating-point	B-General_Concept
unit	I-General_Concept
,	O
although	O
floating-point	B-Algorithm
is	O
currently	O
required	O
for	O
audio	O
bandwidth	O
detection	O
(	O
dynamic	O
switching	O
between	O
SILK	O
,	O
CELT	B-Algorithm
,	O
and	O
hybrid	O
encoding	O
)	O
and	O
most	O
speed	O
optimizations	O
.	O
</s>
<s>
Opus	B-Algorithm
packets	B-Protocol
are	O
not	O
self-delimiting	O
,	O
but	O
are	O
designed	O
to	O
be	O
used	O
inside	O
a	O
container	O
of	O
some	O
sort	O
which	O
supplies	O
the	O
decoder	O
with	O
each	O
packet	B-Protocol
's	O
length	O
.	O
</s>
<s>
Opus	B-Algorithm
was	O
originally	O
specified	O
for	O
encapsulation	O
in	O
Ogg	O
containers	O
,	O
specified	O
as	O
audio/ogg	O
;	O
codecs	O
=	O
opus	B-Algorithm
,	O
and	O
for	O
Ogg	B-Algorithm
Opus	I-Algorithm
files	O
the	O
.opus	B-Algorithm
filename	O
extension	O
is	O
recommended	O
.	O
</s>
<s>
Opus	B-Algorithm
streams	O
are	O
also	O
supported	O
in	O
Matroska	O
,	O
WebM	B-Application
,	O
MPEG-TS	O
,	O
and	O
MP4	O
.	O
</s>
<s>
Alternatively	O
,	O
each	O
Opus	B-Algorithm
packet	B-Protocol
may	O
be	O
wrapped	O
in	O
a	O
network	B-Protocol
packet	I-Protocol
which	O
supplies	O
the	O
packet	B-Protocol
length	O
.	O
</s>
<s>
Opus	B-Algorithm
packets	B-Protocol
may	O
be	O
sent	O
over	O
an	O
ordered	O
datagram	O
protocol	O
such	O
as	O
RTP	B-Protocol
.	O
</s>
<s>
An	O
optional	O
self-delimited	O
packet	B-Protocol
format	O
is	O
defined	O
in	O
an	O
appendix	O
to	O
the	O
specification	O
.	O
</s>
<s>
This	O
uses	O
one	O
or	O
two	O
additional	O
bytes	O
per	O
packet	B-Protocol
to	O
encode	O
the	O
packet	B-Protocol
length	O
,	O
allowing	O
packets	B-Protocol
to	O
be	O
concatenated	O
without	O
encapsulation	O
.	O
</s>
<s>
Opus	B-Algorithm
allows	O
the	O
following	O
bandwidths	O
during	O
encoding	O
.	O
</s>
<s>
Opus	B-Algorithm
compression	O
does	O
not	O
depend	O
on	O
the	O
input	O
sample	O
rate	O
;	O
timestamps	O
are	O
measured	O
in	O
48kHz	O
units	O
even	O
if	O
the	O
full	O
bandwidth	O
is	O
not	O
used	O
.	O
</s>
<s>
Opus	B-Algorithm
was	O
proposed	O
for	O
the	O
standardization	O
of	O
a	O
new	O
audio	O
format	O
at	O
the	O
IETF	O
,	O
which	O
was	O
eventually	O
accepted	O
and	O
granted	O
by	O
the	O
codec	O
working	O
group	O
.	O
</s>
<s>
It	O
is	O
based	O
on	O
two	O
initially	O
separate	O
standard	O
proposals	O
from	O
the	O
Xiph.Org	B-Application
Foundation	I-Application
and	O
Skype	O
Technologies	O
S.A.	O
(	O
now	O
Microsoft	O
)	O
.	O
</s>
<s>
Its	O
main	O
developers	O
are	O
Jean-Marc	O
Valin	O
(	O
Xiph.Org	B-Application
,	O
Octasic	O
,	O
Mozilla	O
Corporation	O
)	O
,	O
Koen	O
Vos	O
(	O
Skype	O
)	O
,	O
and	O
Timothy	O
B	O
.	O
Terriberry	O
(	O
Xiph.Org	B-Application
,	O
Mozilla	O
Corporation	O
)	O
.	O
</s>
<s>
Among	O
others	O
,	O
Juin-Hwey	O
(	O
Raymond	O
)	O
Chen	O
(	O
Broadcom	O
)	O
,	O
Gregory	O
Maxwell	O
(	O
Xiph.Org	B-Application
,	O
Wikimedia	O
)	O
,	O
and	O
Christopher	O
Montgomery	O
(	O
Xiph.Org	B-Application
)	O
were	O
also	O
involved	O
.	O
</s>
<s>
The	O
development	O
of	O
the	O
CELT	B-Algorithm
part	O
of	O
the	O
format	O
goes	O
back	O
to	O
thoughts	O
on	O
a	O
successor	O
for	O
Vorbis	B-Algorithm
under	O
the	O
working	O
name	O
Ghost	O
.	O
</s>
<s>
As	O
a	O
newer	O
speech	B-Application
codec	I-Application
from	O
the	O
Xiph.Org	B-Application
Foundation	I-Application
,	O
Opus	B-Algorithm
replaces	O
Xiph	B-Application
's	O
older	O
speech	B-Application
codec	I-Application
Speex	B-Application
,	O
an	O
earlier	O
project	O
of	O
Jean-Marc	O
Valin	O
.	O
</s>
<s>
CELT	B-Algorithm
has	O
been	O
worked	O
on	O
since	O
November	O
2007	O
.	O
</s>
<s>
The	O
SILK	O
part	O
has	O
been	O
under	O
development	O
at	O
Skype	O
since	O
January	O
2007	O
as	O
the	O
successor	O
of	O
their	O
SVOPC	B-Protocol
,	O
an	O
internal	O
project	O
to	O
make	O
the	O
company	O
independent	O
from	O
third-party	O
codecs	O
like	O
iSAC	B-Algorithm
and	O
iLBC	B-Algorithm
and	O
respective	O
license	O
payments	O
.	O
</s>
<s>
Representatives	O
of	O
several	O
companies	O
which	O
were	O
taking	O
part	O
in	O
the	O
standardization	O
of	O
patent-encumbered	O
competing	O
format	O
,	O
including	O
Polycom	O
and	O
Ericsson	O
—	O
the	O
creators	O
and	O
licensors	O
of	O
G.719	B-Algorithm
—	O
as	O
well	O
as	O
France	O
Télécom	O
,	O
Huawei	O
and	O
the	O
Orange	O
Labs	O
(	O
department	O
of	O
France	O
Télécom	O
)	O
,	O
which	O
were	O
involved	O
in	O
the	O
creation	O
of	O
G.718	B-Algorithm
,	O
stated	O
objections	O
against	O
the	O
start	O
of	O
the	O
standardization	O
process	O
for	O
a	O
royalty-free	O
format	O
.	O
</s>
<s>
(	O
Some	O
of	O
the	O
opponents	O
would	O
later	O
claim	O
patent	O
rights	O
that	O
Xiph	B-Application
dismissed	O
;	O
see	O
below	O
.	O
)	O
</s>
<s>
In	O
July	O
2010	O
,	O
a	O
prototype	O
of	O
a	O
hybrid	O
format	O
was	O
presented	O
that	O
combined	O
the	O
two	O
proposed	O
format	O
candidates	O
SILK	O
and	O
CELT	B-Algorithm
.	O
</s>
<s>
In	O
September	O
2010	O
,	O
Opus	B-Algorithm
was	O
submitted	O
to	O
the	O
IETF	O
as	O
proposal	O
for	O
standardization	O
.	O
</s>
<s>
Near	O
the	O
end	O
of	O
July	O
2011	O
,	O
Jean-Marc	O
Valin	O
was	O
hired	O
by	O
the	O
Mozilla	O
Corporation	O
to	O
continue	O
working	O
on	O
Opus	B-Algorithm
.	O
</s>
<s>
On	O
July	O
2	O
,	O
2012	O
,	O
Opus	B-Algorithm
was	O
approved	O
by	O
the	O
IETF	O
for	O
standardization	O
.	O
</s>
<s>
The	O
final	O
specification	O
was	O
released	O
as	O
RFC	B-Algorithm
6716	I-Algorithm
on	O
September	O
10	O
,	O
2012	O
.	O
and	O
versions	O
1.0	O
and	O
1.0.1	O
of	O
the	O
reference	O
implementation	O
libopus	B-Algorithm
were	O
released	O
the	O
day	O
after	O
.	O
</s>
<s>
On	O
July	O
11	O
,	O
2013	O
,	O
libopus	B-Algorithm
1.0.3	O
brought	O
bug	O
fixes	O
and	O
a	O
new	O
Surround	O
sound	O
API	O
that	O
improves	O
channel	O
allocation	O
and	O
quality	O
,	O
especially	O
for	O
LFE	O
.	O
</s>
<s>
On	O
December	O
5	O
,	O
2013	O
,	O
libopus	B-Algorithm
1.1	O
was	O
released	O
,	O
incorporating	O
overall	O
speed	O
improvements	O
and	O
significant	O
encoder	O
quality	O
improvements	O
:	O
Tonality	O
estimation	O
boosts	O
bitrate	O
and	O
quality	O
for	O
previously	O
,	O
like	O
harpsichords	O
;	O
automated	O
speech/music	O
detection	O
improves	O
quality	O
in	O
mixed	O
audio	O
;	O
mid-side	O
stereo	O
reduces	O
the	O
bitrate	O
needs	O
of	O
many	O
songs	O
;	O
band	O
precision	O
boosting	O
for	O
improved	O
transients	O
;	O
and	O
DC	O
rejection	O
below	O
3Hz	O
.	O
</s>
<s>
Two	O
new	O
VBR	B-General_Concept
modes	O
were	O
added	O
:	O
unconstrained	O
for	O
more	O
consistent	O
quality	O
,	O
and	O
temporal	O
VBR	B-General_Concept
that	O
boosts	O
louder	O
frames	O
and	O
generally	O
improves	O
quality	O
.	O
</s>
<s>
libopus	B-Algorithm
1.1.1	O
was	O
released	O
on	O
November	O
26	O
,	O
2015	O
,	O
and	O
1.1.2	O
on	O
January	O
12	O
,	O
2016	O
,	O
both	O
adding	O
speed	O
optimizations	O
and	O
bug	O
fixes	O
.	O
</s>
<s>
libopus	B-Algorithm
1.2	O
Beta	O
was	O
released	O
on	O
May	O
24	O
,	O
2017	O
.	O
libopus	B-Algorithm
1.2	O
was	O
released	O
on	O
June	O
20	O
,	O
2017	O
.	O
</s>
<s>
libopus	B-Algorithm
1.2	O
includes	O
optional	O
support	O
for	O
the	O
decoder	O
specification	O
changes	O
made	O
in	O
drafts	O
of	O
RFC	O
8251	O
,	O
improving	O
the	O
quality	O
of	O
output	O
from	O
such	O
low-rate	O
streams	O
.	O
</s>
<s>
libopus	B-Algorithm
1.3	O
was	O
released	O
on	O
October	O
18	O
,	O
2018	O
.	O
</s>
<s>
The	O
Opus	B-Algorithm
1.3	O
major	O
release	O
again	O
brings	O
quality	O
improvements	O
,	O
new	O
features	O
,	O
and	O
bug	O
fixes	O
.	O
</s>
<s>
libopus	B-Algorithm
1.3.1	O
was	O
released	O
on	O
April	O
12	O
,	O
2019	O
.	O
</s>
<s>
This	O
Opus	B-Algorithm
1.3.1	O
minor	O
release	O
fixes	O
an	O
issue	O
with	O
the	O
analysis	O
on	O
files	O
with	O
digital	O
silence	O
(	O
all	O
zeros	O
)	O
,	O
especially	O
on	O
x87	B-Application
builds	O
(	O
mostly	O
affects	O
32-bit	O
builds	O
)	O
.	O
</s>
<s>
libopus	B-Algorithm
1.4	O
was	O
released	O
on	O
April	O
20	O
,	O
2023	O
.	O
</s>
<s>
Opus	B-Algorithm
1.4	O
brings	O
the	O
following	O
improvements	O
and	O
fixes	O
:	O
</s>
<s>
Improved	O
tuning	O
of	O
the	O
Opus	B-Algorithm
in-band	O
FEC	O
(	O
LBRR	O
)	O
.	O
</s>
<s>
Opus	B-Algorithm
performs	O
well	O
at	O
both	O
low	O
and	O
high	O
bit	O
rates	O
.	O
</s>
<s>
In	O
listening	O
tests	O
around	O
64	O
kbit/s	O
,	O
Opus	B-Algorithm
shows	O
superior	O
quality	O
compared	O
to	O
HE-AAC	O
codecs	O
,	O
which	O
were	O
previously	O
dominant	O
due	O
to	O
their	O
use	O
of	O
the	O
patented	O
spectral	B-Algorithm
band	I-Algorithm
replication	I-Algorithm
(	O
SBR	O
)	O
technology	O
.	O
</s>
<s>
In	O
listening	O
tests	O
around	O
96	O
kbit/s	O
,	O
Opus	B-Algorithm
shows	O
slightly	O
superior	O
quality	O
compared	O
to	O
AAC	B-Application
and	O
significantly	O
better	O
quality	O
compared	O
to	O
Vorbis	B-Algorithm
and	O
MP3	B-Application
.	O
</s>
<s>
Opus	B-Algorithm
has	O
very	O
low	O
algorithmic	O
delay	O
,	O
a	O
necessity	O
for	O
use	O
as	O
part	O
of	O
a	O
low-audio-latency	O
communication	O
link	O
,	O
which	O
can	O
permit	O
natural	O
conversation	O
,	O
networked	B-Protocol
music	I-Protocol
performances	I-Protocol
,	O
or	O
lip	O
sync	O
at	O
live	O
events	O
.	O
</s>
<s>
Total	O
algorithmic	O
delay	O
for	O
an	O
audio	O
format	O
is	O
the	O
sum	O
of	O
delays	O
that	O
must	O
be	O
incurred	O
in	O
the	O
encoder	O
and	O
the	O
decoder	O
of	O
a	O
live	O
audio	O
stream	O
regardless	O
of	O
processing	O
speed	O
and	O
transmission	O
speed	O
,	O
such	O
as	O
buffering	O
audio	O
samples	O
into	O
blocks	O
or	O
frames	O
,	O
allowing	O
for	O
window	O
overlap	O
and	O
possibly	O
allowing	O
for	O
noise-shaping	O
look-ahead	O
in	O
a	O
decoder	O
and	O
any	O
other	O
forms	O
of	O
look-ahead	O
,	O
or	O
for	O
an	O
MP3	B-Application
encoder	I-Application
,	O
the	O
use	O
of	O
bit	O
reservoir	O
.	O
</s>
<s>
Total	O
one-way	O
latency	O
below	O
150ms	O
is	O
the	O
preferred	O
target	O
of	O
most	O
VoIP	B-Application
systems	O
,	O
to	O
enable	O
natural	O
conversation	O
with	O
turn-taking	O
little	O
affected	O
by	O
delay	O
.	O
</s>
<s>
Opus	B-Algorithm
permits	O
trading-off	O
reduced	O
quality	O
or	O
increased	O
bitrate	O
to	O
achieve	O
an	O
even	O
smaller	O
algorithmic	O
delay	O
(	O
5.0ms	O
minimum	O
)	O
.	O
</s>
<s>
While	O
the	O
reference	O
implementation	O
's	O
default	O
Opus	B-Algorithm
frame	O
is	O
20.0ms	O
long	O
,	O
the	O
SILK	O
layer	O
requires	O
a	O
further	O
5.0ms	O
lookahead	O
plus	O
1.5ms	O
for	O
resampling	O
,	O
giving	O
a	O
default	O
delay	O
of	O
26.5ms	O
.	O
</s>
<s>
When	O
the	O
CELT	B-Algorithm
layer	O
is	O
active	O
,	O
it	O
requires	O
2.5ms	O
lookahead	O
for	O
window	O
overlap	O
to	O
which	O
a	O
matching	O
delay	O
of	O
4.0ms	O
is	O
added	O
by	O
default	O
to	O
synchronize	O
with	O
the	O
SILK	O
layer	O
.	O
</s>
<s>
The	O
format	O
and	O
algorithms	O
are	O
openly	O
documented	O
and	O
the	O
reference	O
implementation	O
is	O
published	O
as	O
free	B-Application
software	I-Application
.	O
</s>
<s>
Xiph	B-Application
's	O
reference	O
implementation	O
is	O
called	O
libopus	B-Algorithm
and	O
a	O
package	O
called	O
opus-tools	B-Algorithm
provides	O
command-line	O
encoder	O
and	O
decoder	O
utilities	O
.	O
</s>
<s>
It	O
is	O
published	O
under	O
the	O
terms	O
of	O
a	O
BSD-like	B-Operating_System
license	I-Operating_System
.	O
</s>
<s>
It	O
is	O
written	O
in	O
C	B-Language
and	O
can	O
be	O
compiled	O
for	O
hardware	O
architectures	O
with	O
or	O
without	O
a	O
floating-point	B-General_Concept
unit	I-General_Concept
.	O
</s>
<s>
The	O
accompanying	O
diagnostic	O
tool	O
opusinfo	O
reports	O
detailed	O
technical	O
information	O
about	O
Opus	B-Algorithm
files	O
,	O
including	O
information	O
on	O
the	O
standard	O
compliance	O
of	O
the	O
bitstream	O
format	O
.	O
</s>
<s>
It	O
is	O
based	O
on	O
ogginfo	O
from	O
the	O
vorbis-tools	O
and	O
therefore	O
—	O
unlike	O
the	O
encoder	O
and	O
decoder	O
—	O
is	O
available	O
under	O
the	O
terms	O
of	O
version	O
2	O
of	O
the	O
GPL	B-License
.	O
</s>
<s>
contains	O
a	O
complete	O
source	O
code	O
for	O
an	O
older	O
version	O
of	O
the	O
reference	O
implementation	O
written	O
in	O
C	B-Language
.	O
RFC	O
contains	O
errata	O
.	O
</s>
<s>
Libopus	B-Algorithm
is	O
the	O
more	O
up-to-date	O
but	O
non-normative	O
branch	O
of	O
the	O
reference	O
implementation	O
.	O
</s>
<s>
The	O
FFmpeg	B-Library
project	O
has	O
encoder	O
and	O
decoder	O
implementations	O
not	O
derived	O
from	O
the	O
reference	O
library	O
.	O
</s>
<s>
The	O
documentation	O
describes	O
it	O
as	O
CELT-only	O
and	O
poorer-quality	O
than	O
the	O
reference	O
.	O
</s>
<s>
The	O
libopus	B-Algorithm
reference	O
library	O
has	O
been	O
ported	O
to	O
both	O
C#	B-Application
and	O
Java	B-Language
as	O
part	O
of	O
a	O
project	O
called	O
Concentus	O
.	O
</s>
<s>
These	O
ports	O
sacrifice	O
performance	O
for	O
the	O
sake	O
of	O
being	O
easily	O
integrated	O
into	O
cross-platform	B-Operating_System
applications	O
.	O
</s>
<s>
Digital	O
Radio	O
Mondiale	O
–	O
a	O
digital	O
radio	O
format	O
for	O
AM	O
frequencies	O
–	O
can	O
broadcast	O
and	O
receive	O
Opus	B-Algorithm
audio	O
(	O
albeit	O
not	O
recognised	O
in	O
official	O
standard	O
)	O
using	O
Dream	O
software-defined	B-Architecture
radio	I-Architecture
.	O
</s>
<s>
The	O
Wikimedia	O
Foundation	O
sponsored	O
a	O
free	O
and	O
open	O
source	O
online	O
JavaScript	B-Language
Opus	B-Algorithm
encoder	O
for	O
browsers	O
supporting	O
the	O
required	O
HTML5	B-Application
features	O
.	O
</s>
<s>
A	O
list	O
of	O
radio	O
stations	O
that	O
stream	O
using	O
Opus	B-Algorithm
audio	B-Algorithm
codec	I-Algorithm
can	O
be	O
found	O
on	O
the	O
Xiph.Org	B-Application
Foundation	I-Application
Icecast	B-Application
directory	O
.	O
</s>
<s>
In	O
late	O
2014	O
and	O
2015	O
,	O
Google	B-Application
's	I-Application
video	O
platform	O
YouTube	B-General_Concept
started	O
offering	O
Opus	B-Algorithm
audio	O
along	O
with	O
VP9	B-Algorithm
video	O
in	O
the	O
WebM	B-Application
file	O
format	O
,	O
through	O
DASH	B-Protocol
streaming	I-Protocol
.	O
</s>
<s>
Since	O
2016	O
,	O
WhatsApp	B-Application
has	O
been	O
using	O
Opus	B-Algorithm
as	O
its	O
audio	O
file	O
format	O
.	O
</s>
<s>
Signal	B-Application
switched	O
from	O
Speex	B-Application
to	O
Opus	B-Algorithm
audio	B-Algorithm
codec	I-Algorithm
for	O
better	O
audio	O
quality	O
in	O
the	O
beginning	O
of	O
2017	O
.	O
</s>
<s>
In	O
2018	O
,	O
SoundCloud	O
switched	O
from	O
MP3	B-Application
to	O
Opus	B-Algorithm
,	O
reducing	O
half	O
of	O
its	O
required	O
bandwidth	O
for	O
music	O
streaming	O
.	O
</s>
<s>
In	O
January	O
2021	O
,	O
Vimeo	O
introduced	O
Opus	B-Algorithm
to	O
its	O
video	O
platform	O
.	O
</s>
<s>
In	O
2021	O
,	O
the	O
Danish	O
journalism	O
website	O
Zetland	O
switched	O
from	O
MP3	B-Application
to	O
Opus	B-Algorithm
for	O
its	O
articles	O
 '	O
audio	O
recordings	O
,	O
which	O
attained	O
a	O
35	O
percent	O
reduction	O
in	O
bandwidth	O
and	O
reduced	O
climate	O
footprint	O
.	O
</s>
<s>
Most	O
end-user	O
software	O
relies	O
on	O
multimedia	B-Library
frameworks	I-Library
provided	O
by	O
the	O
operating	B-General_Concept
system	I-General_Concept
.	O
</s>
<s>
Native	O
Opus	B-Algorithm
codec	I-Algorithm
support	O
is	O
implemented	O
in	O
most	O
major	O
multimedia	B-Library
frameworks	I-Library
for	O
Unix-like	B-Operating_System
operating	I-Operating_System
systems	I-Operating_System
,	O
including	O
GStreamer	B-Language
,	O
FFmpeg	B-Library
,	O
and	O
Libav	B-Language
libraries	O
.	O
</s>
<s>
The	O
WebM	B-Application
container	O
.webm	B-Application
is	O
mostly	O
used	O
on	O
online	O
video	O
platforms	O
(	O
e.g.	O
</s>
<s>
YouTube	B-General_Concept
)	O
,	O
and	O
is	O
usually	O
treated	O
as	O
a	O
video	O
file	O
by	O
operating	B-General_Concept
systems	I-General_Concept
&	O
media	B-Device
players	I-Device
.	O
</s>
<s>
Even	O
if	O
a	O
WebM	B-Application
file	O
contains	O
only	O
Opus	B-Algorithm
audio	O
and	O
no	O
video	O
,	O
some	O
music	O
players	O
do	O
not	O
recognize	O
WebM	B-Application
files	O
as	O
audio	O
files	O
and	O
do	O
not	O
support	O
reading	O
of	O
file	O
metadata	O
.	O
</s>
<s>
The	O
Ogg	O
container	O
.opus	B-Algorithm
is	O
preferred	O
for	O
audio-only	O
files	O
,	O
and	O
most	O
media	B-Device
players	I-Device
have	O
support	O
for	O
audio	O
file	O
metadata	O
tagged	O
in	O
the	O
Vorbis	B-Algorithm
comment	O
format	O
.	O
</s>
<s>
Google	B-Application
added	O
native	O
support	O
for	O
Opus	B-Algorithm
audio	O
playback	O
in	O
Android	B-Application
5.0	I-Application
"	I-Application
Lollipop	I-Application
"	I-Application
.	O
</s>
<s>
However	O
,	O
it	O
was	O
limited	O
to	O
Opus	B-Algorithm
audio	O
encapsulated	O
in	O
Matroska	O
and	O
WebM	B-Application
containers	O
,	O
such	O
as	O
.mkv	O
,	O
.mka	O
and	O
.webm	B-Application
files	O
.	O
</s>
<s>
Android	B-Application
7.0	I-Application
"	I-Application
Nougat	I-Application
"	I-Application
introduced	O
support	O
for	O
Opus	B-Algorithm
audio	O
encapsulated	O
in	O
Ogg	O
containers	O
.	O
</s>
<s>
Android	B-Application
10	I-Application
finally	O
added	O
native	O
support	O
for	O
.opus	B-Algorithm
extensions	O
.	O
</s>
<s>
Due	O
to	O
the	O
addition	O
of	O
WebRTC	B-Protocol
support	O
in	O
Apple	O
's	O
WebKit	B-Language
rendering	O
engine	O
,	O
macOS	B-Operating_System
High	I-Operating_System
Sierra	I-Operating_System
and	O
iOS	B-Operating_System
11	I-Operating_System
come	O
with	O
native	O
playback	O
support	O
for	O
Opus	B-Algorithm
audio	O
encapsulated	O
in	O
Core	B-Application
Audio	I-Application
Format	I-Application
containers	O
.	O
</s>
<s>
On	O
Windows	B-Operating_System
10	I-Operating_System
,	O
version	O
1607	O
,	O
Microsoft	O
provided	O
native	O
support	O
for	O
Opus	B-Algorithm
audio	O
encapsulated	O
in	O
Matroska	O
and	O
WebM	B-Application
containers	O
.	O
</s>
<s>
On	O
version	O
1709	O
,	O
support	O
for	O
Opus	B-Algorithm
audio	O
encapsulated	O
in	O
Ogg	O
containers	O
was	O
made	O
available	O
through	O
a	O
pre-installed	O
add-on	O
called	O
Web	O
Media	O
Extensions	O
.	O
</s>
<s>
On	O
Windows	B-Operating_System
10	I-Operating_System
version	O
1903	O
,	O
native	O
support	O
for	O
the	O
.opus	B-Algorithm
extension	O
was	O
added	O
.	O
</s>
<s>
On	O
Windows	B-Device
8.1	I-Device
and	O
older	O
,	O
third-party	O
decoders	O
,	O
such	O
as	O
LAV	O
Filters	O
,	O
are	O
available	O
to	O
provide	O
support	O
for	O
the	O
format	O
.	O
</s>
<s>
+	O
Opus	B-Algorithm
support	O
by	O
different	O
operating	B-General_Concept
systems	I-General_Concept
Windows	B-Application
macOS	B-Application
Linux	B-Application
Android	B-Application
iOS	B-Application
Codec	O
support	O
Container	O
support	O
On	O
Windows	B-Operating_System
10	I-Operating_System
Anniversary	O
Update	O
(	O
1607	O
)	O
:WebM	O
(	O
.webm	B-Application
is	O
not	O
recognised	O
;	O
requires	O
pseudo	O
extension	O
)	O
Matroska	O
(	O
.mka	O
,	O
.mkv	O
)	O
On	O
Windows	B-Operating_System
10	I-Operating_System
Fall	O
Creators	O
Update	O
(	O
1709	O
)	O
with	O
Web	O
Media	O
Extensions	O
add-on:Ogg	O
(	O
.opus	B-Algorithm
is	O
not	O
recognised	O
;	O
requires	O
pseudo	O
extension	O
)	O
On	O
Windows	B-Operating_System
10	I-Operating_System
October	O
2018	O
Update	O
(	O
1809	O
)	O
:WebM	O
(	O
.webm	B-Application
is	O
recognised	O
officially	O
)	O
On	O
Windows	B-Operating_System
10	I-Operating_System
May	O
2019	O
Update	O
(	O
1903	O
)	O
:	O
Ogg	O
(	O
.opus	B-Algorithm
,	O
.oga	B-Algorithm
,	O
.ogg	O
)	O
(	O
.opus	B-Algorithm
is	O
recognised	O
officially	O
)	O
On	O
macOS	B-Application
High	O
Sierra:Core	O
Audio	O
Format	O
(	O
.caf	B-Application
)	O
On	O
macOS	B-Application
Monterey:WebM	O
(	O
.webm	B-Application
;	O
experimental	O
support	O
)	O
Ogg	O
(	O
.opus	B-Algorithm
)	O
WebM	B-Application
(	O
.webm	B-Application
)	O
Matroska	O
(	O
.mka	O
,	O
.mkv	O
)	O
MPEG-TS	O
(	O
.ts	O
)	O
On	O
Android	B-Application
5:WebM	O
(	O
.webm	B-Application
)	O
Matroska	O
(	O
.mka	O
,	O
.mkv	O
)	O
On	O
Android	B-Application
7:Ogg	O
(	O
.oga	B-Algorithm
,	O
.ogg	O
)	O
(	O
.opus	B-Algorithm
is	O
not	O
recognised	O
;	O
requires	O
pseudo	O
extension	O
)	O
On	O
Android	B-Application
10	I-Application
:	O
Ogg	O
(	O
.opus	B-Algorithm
,	O
.oga	B-Algorithm
,	O
.ogg	O
)	O
(	O
.opus	B-Algorithm
is	O
recognised	O
officially	O
)	O
On	O
iOS	B-Application
11:Core	O
Audio	O
Format	O
(	O
.caf	B-Application
)	O
Notes	O
On	O
Windows	B-Operating_System
10	I-Operating_System
:	O
-	O
On	O
Anniversary	O
Update	O
(	O
1607	O
)	O
,	O
limited	O
support	O
is	O
available	O
in	O
Microsoft	B-Application
Edge	I-Application
(	O
via	O
MSE	B-Language
only	O
)	O
and	O
Universal	B-Device
Windows	I-Device
Platform	I-Device
apps	O
.	O
</s>
<s>
Windows	B-Device
Media	I-Device
Player	I-Device
does	O
not	O
support	O
Ogg	O
;	O
only	O
WebM	B-Application
and	O
Matroska.	O
-	O
On	O
April	O
2018	O
Update	O
(	O
1803	O
)	O
with	O
Web	O
Media	O
Extensions	O
preinstalled	O
,	O
Microsoft	B-Application
Edge	I-Application
(	O
EdgeHTML	O
17	O
)	O
supports	O
Opus	B-Algorithm
audio	O
embedded	O
in	O
<audio>	O
tags.	O
-	O
Up	O
till	O
October	O
2018	O
update	O
(	O
1809	O
)	O
,	O
the	O
filename	O
extension	O
.opus	B-Algorithm
was	O
not	O
recognised	O
.	O
</s>
<s>
(	O
substitute	O
with	O
a	O
pseudo	O
file	O
extension	O
such	O
as	O
.m4a	O
)	O
On	O
Windows	B-Device
8.1	I-Device
and	O
older	O
:	O
-	O
Requires	O
installation	O
of	O
a	O
third-party	O
multimedia	B-Library
framework	I-Library
,	O
LAV	O
Filters	O
.	O
</s>
<s>
Only	O
Opus	B-Algorithm
audio	O
in	O
a	O
CAF	O
container	O
is	O
supported	O
.	O
</s>
<s>
In	O
Safari	O
15	O
,	O
Apple	O
added	O
support	O
for	O
Opus	B-Algorithm
audio	O
in	O
WebM	B-Application
containers	O
.	O
</s>
<s>
Experimental	O
support	O
is	O
only	O
present	O
in	O
macOS	B-Application
.	O
</s>
<s>
–	O
-	O
Up	O
till	O
Android	B-Application
9	O
,	O
the	O
filename	O
extension	O
.opus	B-Algorithm
was	O
not	O
recognised	O
(	O
substitute	O
with	O
a	O
pseudo	O
file	O
extension	O
such	O
as	O
.ogg	O
or	O
.m4a	O
)	O
Only	O
Opus	B-Algorithm
audio	O
in	O
a	O
CAF	O
container	O
is	O
supported	O
.	O
</s>
<s>
In	O
Safari	O
15	O
,	O
Apple	O
added	O
support	O
for	O
Opus	B-Algorithm
audio	O
in	O
WebM	B-Application
containers	O
.	O
</s>
<s>
However	O
,	O
it	O
is	O
non-functional	O
in	O
iOS	B-Application
15	O
,	O
as	O
of	O
September	O
2021	O
.	O
</s>
<s>
While	O
support	O
in	O
multimedia	B-Library
frameworks	I-Library
automatically	O
enables	O
Opus	B-Algorithm
support	O
in	O
software	O
which	O
is	O
built	O
on	O
top	O
of	O
such	O
frameworks	O
,	O
several	O
applications	O
developers	O
made	O
additional	O
efforts	O
for	O
supporting	O
the	O
Opus	B-Algorithm
audio	I-Algorithm
format	I-Algorithm
in	O
their	O
software	O
.	O
</s>
<s>
Such	O
support	O
was	O
added	O
to	O
AIMP	B-Application
,	O
Amarok	B-Language
,	O
cmus	B-Language
,	O
Music	B-Language
Player	I-Language
Daemon	I-Language
,	O
foobar2000	B-Application
,	O
Mpxplay	O
,	O
MusicBee	B-Application
,	O
SMplayer	B-Language
,	O
VLC	B-Application
media	I-Application
player	I-Application
,	O
Winamp	B-Application
and	O
Xmplay	O
audio	O
players	O
;	O
Icecast	B-Application
,	O
Airtime	O
(	O
software	O
)	O
audio	O
streaming	O
software	O
;	O
and	O
Asunder	B-Language
audio	O
CD	O
ripper	O
,	O
CDBurnerXP	B-Application
CD	O
burner	O
,	O
FFmpeg	B-Library
,	O
Libav	B-Language
and	O
MediaCoder	B-Algorithm
media	O
encoding	O
tools	O
.	O
</s>
<s>
Streaming	O
Icecast	B-Application
radio	O
trials	O
are	O
live	O
since	O
September	O
2012	O
and	O
January	O
2013	O
.	O
</s>
<s>
SteamOS	B-Application
uses	O
Opus	B-Algorithm
or	O
Vorbis	B-Algorithm
for	O
streaming	O
audio	O
.	O
</s>
<s>
Opus	B-Algorithm
support	O
is	O
mandatory	O
for	O
WebRTC	B-Protocol
implementations	O
.	O
</s>
<s>
Opus	B-Algorithm
is	O
supported	O
in	O
Mozilla	B-Application
Firefox	I-Application
,	O
Chromium	B-Language
and	O
Google	B-Application
Chrome	I-Application
,	O
Blink-based	O
Opera	B-Application
,	O
as	O
well	O
as	O
all	O
browsers	O
for	O
Unix-like	B-Operating_System
systems	I-Operating_System
relying	O
on	O
GStreamer	B-Language
for	O
multimedia	O
formats	O
support	O
.	O
</s>
<s>
Although	O
Internet	B-Application
Explorer	I-Application
will	O
not	O
provide	O
Opus	B-Algorithm
playback	O
natively	O
,	O
support	O
for	O
the	O
format	O
is	O
built	O
into	O
the	O
Edge	B-Application
browser	I-Application
,	O
along	O
with	O
VP9	B-Algorithm
,	O
for	O
full	O
WebM	B-Application
support	O
.	O
</s>
<s>
Safari	O
supports	O
Opus	B-Algorithm
as	O
of	O
iOS	B-Operating_System
11	I-Operating_System
and	O
macOS	B-Operating_System
High	I-Operating_System
Sierra	I-Operating_System
.	O
</s>
<s>
Due	O
to	O
its	O
abilities	O
,	O
Opus	B-Algorithm
gained	O
early	O
interest	O
from	O
voice	B-Application
over	I-Application
IP	I-Application
(	O
VoIP	B-Application
)	O
software	O
vendors	O
.	O
</s>
<s>
Several	O
SIP	B-Application
clients	O
,	O
including	O
Acrobits	B-Protocol
Softphone	I-Protocol
,	O
CSipSimple	B-Application
(	O
via	O
additional	O
plug-in	O
)	O
,	O
Empathy	B-Language
(	O
via	O
GStreamer	B-Language
)	O
,	O
Jitsi	B-Protocol
,	O
Tuenti	O
,	O
Line2	O
(	O
currently	O
only	O
on	O
iOS	B-Application
)	O
,	O
Linphone	B-Protocol
,	O
Phoner	B-Application
and	O
PhonerLite	B-Application
,	O
SFLphone	B-Protocol
,	O
Telephone	B-Language
,	O
Mumble	B-Language
,	O
Discord	B-Application
and	O
TeamSpeak	B-Language
3	I-Language
voice	O
chat	O
software	O
also	O
support	O
Opus	B-Algorithm
.	O
</s>
<s>
TrueConf	O
supports	O
Opus	B-Algorithm
in	O
its	O
VoIP	B-Application
products	O
.	O
</s>
<s>
Asterisk	B-Language
lacked	O
builtin	O
Opus	B-Algorithm
support	O
for	O
legal	O
reasons	O
,	O
but	O
a	O
third-party	O
patch	O
was	O
available	O
for	O
download	O
and	O
official	O
support	O
via	O
a	O
binary	O
blob	O
was	O
added	O
in	O
September	O
2016	O
.	O
</s>
<s>
Tox	B-Protocol
P2P	I-Protocol
videoconferencing	I-Protocol
software	I-Protocol
uses	O
Opus	B-Algorithm
exclusively	O
.	O
</s>
<s>
Classified-ads	O
distributed	O
messaging	O
app	O
sends	O
raw	O
opus	B-Algorithm
frames	O
inside	O
TLS	O
socket	O
in	O
its	O
VoIP	B-Application
implementation	O
.	O
</s>
<s>
Opus	B-Algorithm
is	O
widely	O
used	O
as	O
the	O
voice	B-Application
codec	I-Application
in	O
WhatsApp	B-Application
,	O
which	O
has	O
over	O
1.5billion	O
users	O
worldwide	O
.	O
</s>
<s>
WhatsApp	B-Application
uses	O
Opus	B-Algorithm
at	O
816	O
kHz	O
sampling	O
rates	O
,	O
with	O
the	O
Real-time	B-Protocol
Transport	I-Protocol
Protocol	I-Protocol
(	O
RTP	B-Protocol
)	O
.	O
</s>
<s>
The	B-Operating_System
PlayStation	I-Operating_System
4	I-Operating_System
video	O
game	O
console	O
also	O
uses	O
the	O
CELT/Opus	O
codec	O
for	O
its	O
PlayStation	B-Device
Network	I-Device
system	O
party	O
chat	O
.	O
</s>
<s>
It	O
is	O
also	O
used	O
in	O
the	O
Zoom	O
videoconferencing	B-Application
app	O
.	O
</s>
<s>
Since	O
version	O
3.13	O
,	O
Rockbox	B-Application
enables	O
Opus	B-Algorithm
playback	O
on	O
supported	O
portable	O
media	B-Device
players	I-Device
,	O
including	O
some	O
products	O
from	O
the	B-Device
iPod	I-Device
series	O
by	O
Apple	O
,	O
devices	O
made	O
by	O
iriver	O
,	O
Archos	O
and	O
Sandisk	O
,	O
and	O
on	O
Android	B-Application
devices	O
using	O
"	O
Rockbox	B-Application
as	O
an	O
Application	O
"	O
.	O
</s>
<s>
All	O
recent	O
Grandstream	O
IP	B-Device
phones	I-Device
support	O
Opus	B-Algorithm
audio	O
both	O
for	O
encoding	O
and	O
decoding	O
.	O
</s>
<s>
OBihai	O
OBi1062	O
,	O
OBi1032	O
and	O
OBi1022	O
IP	B-Device
phones	I-Device
all	O
support	O
Opus	B-Algorithm
.	O
</s>
<s>
Recent	O
BlueSound	O
wireless	O
speakers	O
support	O
Opus	B-Algorithm
playback	O
.	O
</s>
<s>
Devices	O
running	O
Hiby	O
OS	O
,	O
like	O
the	O
Hiby	O
R3	O
,	O
are	O
capable	O
of	O
decoding	O
Opus	B-Algorithm
files	O
natively	O
.	O
</s>
<s>
Many	O
broadcast	O
IP	O
codecs	O
include	O
Opus	B-Algorithm
such	O
as	O
those	O
manufactured	O
by	O
Comrex	O
,	O
GatesAir	O
and	O
Tieline	O
.	O
</s>
<s>
The	O
Sony	B-Device
PlayStation	I-Device
5	I-Device
supports	O
capturing	O
1080p	O
and	O
2160p	O
footage	O
using	O
VP9	B-Algorithm
video	O
and	O
Opus	B-Algorithm
audio	O
in	O
a	O
WebM	B-Application
container	O
.	O
</s>
<s>
Broadcom	O
and	O
the	O
Xiph.Org	B-Application
Foundation	I-Application
own	O
software	O
patents	O
on	O
some	O
of	O
the	O
CELT	B-Algorithm
algorithms	O
,	O
and	O
Skype	O
Technologies/Microsoft	O
own	O
some	O
on	O
the	O
SILK	O
algorithms	O
;	O
each	O
offers	O
a	O
royalty-free	O
perpetual	O
license	O
for	O
use	O
with	O
Opus	B-Algorithm
,	O
reserving	O
only	O
the	O
right	O
to	O
make	O
use	O
of	O
their	O
patents	O
to	O
defend	O
against	O
infringement	O
suits	O
of	O
third	O
parties	O
.	O
</s>
<s>
Qualcomm	O
,	O
Huawei	O
,	O
France	O
Telecom	O
,	O
and	O
Ericsson	O
have	O
claimed	O
that	O
their	O
patents	O
may	O
apply	O
,	O
which	O
Xiph	B-Application
's	O
legal	O
counsel	O
denies	O
,	O
and	O
none	O
have	O
pursued	O
any	O
legal	O
action	O
.	O
</s>
<s>
The	O
Opus	B-Algorithm
license	O
automatically	O
and	O
retroactively	O
terminates	O
for	O
any	O
entity	O
that	O
attempts	O
to	O
file	O
a	O
patent	O
suit	O
.	O
</s>
<s>
In	O
September	O
of	O
2022	O
,	O
UK-based	O
Vectis	O
IP	O
Ltd	O
announced	O
their	O
plans	O
to	O
collect	O
and	O
enforce	O
any	O
available	O
patents	O
to	O
extract	O
royalties	O
from	O
manufacturers	O
of	O
hardware	O
using	O
Opus	B-Algorithm
,	O
via	O
a	O
then	O
upcoming	O
patent	O
pool	O
for	O
Opus	B-Algorithm
.	O
</s>
<s>
PCs	O
,	O
smartphones	O
,	O
IP	B-Device
phones	I-Device
,	O
smart	O
TVs	O
)	O
.	O
</s>
