<s>
Jamulus	B-Application
is	O
open	B-License
source	I-License
(	O
GPL	B-License
)	O
networked	B-Protocol
music	I-Protocol
performance	I-Protocol
software	O
that	O
enables	O
live	O
rehearsing	O
,	O
jamming	O
and	O
performing	O
with	O
musicians	O
located	O
anywhere	O
on	O
the	O
internet	O
.	O
</s>
<s>
Jamulus	B-Application
is	O
written	O
by	O
Volker	O
Fischer	O
and	O
contributors	O
using	O
C++	B-Language
.	O
</s>
<s>
The	O
Software	O
is	O
based	O
on	O
the	O
Qt	B-Language
framework	I-Language
and	O
uses	O
the	O
OPUS	B-Algorithm
audio	B-Algorithm
codec	I-Algorithm
.	O
</s>
<s>
A	O
further	O
problem	O
is	O
jitter	O
,	O
a	O
type	O
of	O
packet	B-Protocol
delay	I-Protocol
due	O
to	O
changes	O
in	O
latency	O
over	O
time	O
,	O
which	O
results	O
in	O
choppy	O
or	O
distorted	O
sound	O
.	O
</s>
<s>
Long	O
delays	O
can	O
even	O
lead	O
to	O
packet	B-Protocol
loss	I-Protocol
(	O
perceived	O
as	O
a	O
'	O
blackout	O
 '	O
)	O
.	O
</s>
<s>
These	O
can	O
be	O
alleviated	O
by	O
delay	O
buffers	O
or	O
jitter	O
buffers	O
(	O
both	O
of	O
which	O
are	O
present	O
in	O
Jamulus	B-Application
)	O
-	O
but	O
these	O
then	O
add	O
to	O
the	O
overall	O
round-trip	O
delay	O
,	O
so	O
need	O
to	O
be	O
balanced	O
.	O
</s>
<s>
Popular	O
video	B-Application
conferencing	I-Application
software	I-Application
such	O
as	O
Zoom	B-Application
or	O
Teams	B-Application
is	O
unsuited	O
to	O
this	O
task	O
as	O
the	O
latency	O
can	O
be	O
much	O
higher	O
(	O
Zoom	B-Application
recommends	O
"	O
a	O
latency	O
of	O
150ms	O
or	O
less	O
"	O
and	O
jitter	O
of	O
"	O
40ms	O
or	O
less	O
"	O
,	O
and	O
in	O
some	O
2020	O
tests	O
was	O
shown	O
to	O
have	O
an	O
average	O
latency	O
of	O
135	O
ms	O
;	O
the	O
"	O
Audio	O
poor	O
quality	O
metrics	O
"	O
for	O
Teams	B-Application
include	O
having	O
"	O
Round-trip	O
time	O
>500	O
ms	O
"	O
and	O
"	O
Jitter	O
>30	O
ms	O
"	O
)	O
.	O
</s>
<s>
In	O
addition	O
,	O
conferencing	O
software	O
does	O
not	O
normally	O
allow	O
detailed	O
setting	O
of	O
individual	O
audio	O
streams	O
 '	O
volume	O
or	O
panning	O
on	O
the	O
user	O
side	O
,	O
both	O
of	O
which	O
are	O
integral	O
features	O
of	O
Jamulus	B-Application
.	O
</s>
<s>
To	O
reduce	O
latency	O
as	O
much	O
as	O
possible	O
,	O
Jamulus	B-Application
makes	O
use	O
of	O
compressed	O
audio	O
and	O
the	O
UDP	B-Protocol
protocol	I-Protocol
to	O
transmit	O
audio	O
data	O
.	O
</s>
<s>
network	B-Protocol
latency	I-Protocol
due	O
to	O
delays	O
within	O
the	O
network	O
-	O
every	O
300km	O
is	O
responsible	O
for	O
at	O
least	O
1	O
ms	O
extra	O
latency	O
since	O
the	O
speed	O
of	O
light	O
limits	O
the	O
data	O
transport	O
on	O
internet	O
.	O
</s>
<s>
Jamulus	B-Application
is	O
client-server	O
based	O
;	O
each	O
client	O
transmits	O
its	O
own	O
compressed	O
audio	O
to	O
a	O
server	O
on	O
the	O
internet	O
.	O
</s>
<s>
Servers	O
can	O
be	O
either	O
public	O
or	O
private	O
(	O
termed	O
"	O
Registered	O
"	O
and	O
"	O
Unregistered	O
"	O
,	O
since	O
Jamulus	B-Application
has	O
no	O
built-in	O
user	O
authentication	O
mechanism	O
)	O
,	O
the	O
former	O
being	O
listed	O
by	O
"	O
directories	O
"	O
from	O
which	O
users	O
can	O
choose	O
a	O
server	O
with	O
the	O
lowest	O
latency	O
for	O
them	O
.	O
</s>
<s>
Already	O
in	O
2018	O
,	O
Jamulus	B-Application
was	O
attracting	O
attention	O
as	O
a	O
way	O
for	O
classical	O
ensembles	O
such	O
as	O
string	O
quartets	O
to	O
rehearse	O
at	O
a	O
distance	O
,	O
but	O
its	O
usage	O
increased	O
dramatically	O
in	O
2020	O
due	O
to	O
the	O
COVID-19	O
pandemic	O
.	O
</s>
<s>
It	O
was	O
elected	O
SourceForge	B-Application
'	O
Project	O
of	O
the	O
Month	O
 '	O
in	O
June	O
2020	O
.	O
</s>
<s>
Jamulus	B-Application
Storband	O
,	O
Sweden	O
's	O
first	O
"	O
virtual	O
big	O
band	O
"	O
with	O
over	O
20	O
members	O
,	O
also	O
started	O
that	O
month	O
.	O
</s>
<s>
Numerous	O
online	O
metronomes	O
are	O
available	O
,	O
or	O
other	O
OpenSource	B-License
tools	O
may	O
be	O
used	O
:	O
as	O
one	O
example	O
,	O
Sychronome	O
uses	O
NTP	O
(	O
Network	O
Time	O
Protocol	O
)	O
with	O
a	O
network	O
time	O
server	O
to	O
sync	O
metronomes	O
for	O
each	O
Jamulus	B-Application
client	O
via	O
smartphones	O
.	O
</s>
