<s>
There	O
are	O
four	O
major	O
forms	O
of	O
digital	B-Application
television	I-Application
(	O
DTV	O
)	O
broadcast	O
in	O
the	O
United	O
Kingdom	O
:	O
a	O
direct-to-home	B-Application
satellite	I-Application
service	O
from	O
the	O
Astra	O
28.2	O
°E	O
satellites	B-Application
provided	O
by	O
Sky	O
UK	O
,	O
a	O
cable	O
television	O
service	O
provided	O
by	O
Virgin	O
Media	O
(	O
known	O
as	O
Virgin	O
TV	O
)	O
;	O
a	O
free-to-air	O
satellite	B-Application
service	O
called	O
Freesat	O
;	O
and	O
a	O
free-to-air	O
digital	B-Application
terrestrial	I-Application
service	O
called	O
Freeview	B-Device
.	O
</s>
<s>
77%	O
of	O
the	O
United	O
Kingdom	O
has	O
access	O
to	O
HDTV	B-Device
via	O
terrestrial	B-Application
digital	I-Application
television	I-Application
.	O
</s>
<s>
Satellite	B-Application
is	O
the	O
only	O
source	O
of	O
HDTV	B-Device
broadcast	O
available	O
for	O
the	O
remaining	O
23%	O
.	O
</s>
<s>
The	O
initial	O
attempt	O
at	O
launching	O
a	O
digital	B-Application
terrestrial	I-Application
broadcasting	O
service	O
,	O
ONdigital	O
(	O
later	O
called	O
ITV	O
Digital	O
)	O
,	O
was	O
unsuccessful	O
and	O
the	O
company	O
went	O
into	O
liquidation	O
.	O
</s>
<s>
ITV	O
Digital	O
was	O
replaced	O
in	O
late	O
2002	O
by	O
Freeview	B-Device
,	O
which	O
uses	O
the	O
same	O
DVB-T	O
technology	O
,	O
but	O
with	O
higher	O
levels	O
of	O
error	B-Error_Name
correction	I-Error_Name
and	O
more	O
robust	O
(	O
but	O
lower-capacity	O
)	O
modulation	O
on	O
the	O
"	O
Public	O
Service	O
"	O
multiplexes	O
in	O
an	O
attempt	O
to	O
counter	O
the	O
reception	O
problems	O
which	O
dogged	O
its	O
predecessor	O
.	O
</s>
<s>
Rather	O
than	O
concentrating	O
on	O
Pay	O
TV	O
services	O
,	O
Freeview	B-Device
uses	O
the	O
available	O
capacity	O
to	O
provide	O
a	O
free-to-air	O
service	O
that	O
includes	O
all	O
the	O
existing	O
five	O
free-to-air	O
analogue	O
terrestrial	O
channels	O
and	O
about	O
twenty	O
new	O
digital	O
channels	O
.	O
</s>
<s>
All	O
services	O
are	O
transmitted	O
in	O
standard	B-Device
definition	I-Device
—	O
576i	O
in	O
the	O
UK	O
—	O
many	O
using	O
an	O
anamorphic	O
widescreen	O
format	O
.	O
</s>
<s>
31	O
March	O
2004	O
saw	O
the	O
return	O
of	O
a	O
limited	O
pay-television	O
offering	O
to	O
the	O
digital	B-Application
terrestrial	I-Application
platform	O
with	O
the	O
launch	O
of	O
Top	O
Up	O
TV	O
.	O
</s>
<s>
Now	O
over	O
100	O
programs	O
are	O
broadcast	O
overnight	O
and	O
added	O
to	O
the	O
box	O
's	O
hard	B-Device
disk	I-Device
,	O
so	O
that	O
it	O
may	O
be	O
watched	O
at	O
any	O
time	O
.	O
</s>
<s>
The	O
residents	O
of	O
Ferryside	O
and	O
Llansteffan	O
in	O
Carmarthenshire	O
,	O
Wales	O
who	O
had	O
not	O
already	O
upgraded	O
to	O
digital	B-Application
television	I-Application
were	O
given	O
a	O
free	O
set-top	O
box	O
to	O
receive	O
the	O
Freeview	B-Device
television	O
service	O
,	O
which	O
includes	O
Channel	O
4	O
(	O
previously	O
unavailable	O
terrestrially	O
from	O
transmitters	O
in	O
Wales	O
)	O
and	O
S4C	O
~	O
2	O
,	O
which	O
broadcasts	O
sessions	O
of	O
the	O
National	O
Assembly	O
for	O
Wales	O
.	O
</s>
<s>
The	O
pilot	O
paved	O
the	O
way	O
for	O
full	O
switch-over	O
to	O
digital	B-Application
television	I-Application
signals	O
throughout	O
the	O
United	O
Kingdom	O
by	O
the	O
Government	O
's	O
deadline	O
of	O
2012	O
.	O
</s>
<s>
Freeview	B-Device
HD	O
launched	O
in	O
December	O
2009	O
,	O
from	O
the	O
Crystal	O
Palace	O
and	O
Winter	O
Hill	O
transmitters	O
,	O
to	O
coincide	O
with	O
digital	O
switchover	O
at	O
the	O
latter	O
.	O
</s>
<s>
BBC	O
HD	O
,	O
ITV	O
HD	O
,	O
BBC	O
One	O
HD	O
and	O
Channel	O
4	O
HD	O
are	O
the	O
currently	O
available	O
terrestrial	O
HDTV	B-Device
channels	O
.	O
</s>
<s>
The	O
broadcast	O
mode	O
is	O
DVB-T2	B-Protocol
,	O
using	O
MPEG4	O
encoding	O
.	O
</s>
<s>
The	O
BBC	O
,	O
ITV	O
,	O
Channel	O
4	O
and	O
Channel	O
5	O
ran	O
terrestrial	O
HDTV	B-Device
trials	O
involving	O
450	O
homes	O
in	O
the	O
London	O
area	O
during	O
June	O
–	O
December	O
2006	O
on	O
locally	O
unused	O
frequencies	O
.	O
</s>
<s>
Trials	O
of	O
the	O
UK	O
's	O
first	O
HDTV	B-Device
service	O
began	O
on	O
2	O
December	O
2005	O
.	O
</s>
<s>
Telewest	O
,	O
a	O
cable	O
TV	O
company	O
now	O
part	O
of	O
Virgin	O
Media	O
,	O
distributed	O
HDTV	B-Device
programs	O
to	O
400	O
customers	O
in	O
the	O
south	O
London	O
area	O
.	O
</s>
<s>
Following	O
the	O
merger	O
of	O
NTL	O
&	O
Telewest	O
and	O
the	O
creation	O
of	O
Virgin	O
Media	O
,	O
HDTV	B-Device
was	O
rolled	O
out	O
across	O
the	O
network	O
,	O
including	O
former	O
NTL	O
areas	O
.	O
</s>
<s>
The	O
service	O
is	O
provided	O
via	O
a	O
personal	B-Application
video	I-Application
recorder	I-Application
,	O
branded	O
as	O
V+	B-Device
and	O
formally	O
known	O
as	O
TV	B-Device
Drive	I-Device
.	O
</s>
<s>
On	O
1	O
November	O
2005	O
ITV	O
turned	O
off	O
encryption	B-Device
on	O
all	O
of	O
its	O
satellite	B-Application
based	O
signals	O
,	O
following	O
the	O
lead	O
from	O
the	O
BBC	O
.	O
</s>
<s>
These	O
transmissions	O
are	O
on	O
a	O
limited	O
spotbeam	O
which	O
is	O
aimed	O
primarily	O
towards	O
the	O
United	O
Kingdom	O
,	O
via	O
the	O
Astra	O
2D	O
satellite	B-Application
located	O
at	O
28.2	O
°	O
east	O
.	O
</s>
<s>
The	O
BBC	O
is	O
broadcasting	O
BBC	O
HD	O
as	O
a	O
free-to-air	O
channel	O
from	O
the	O
Astra	O
2D	O
satellite	B-Application
,	O
and	O
the	O
channel	O
can	O
be	O
viewed	O
for	O
free	O
with	O
suitable	O
satellite	B-Application
reception	O
equipment	O
.	O
</s>
<s>
Sky	O
also	O
offers	O
a	O
free-to-air	O
version	O
of	O
its	O
regular	O
Sky	O
service	O
known	O
as	O
Freesat	B-Application
from	I-Application
Sky	I-Application
.	O
</s>
<s>
Freesat	B-Application
from	I-Application
Sky	I-Application
provides	O
a	O
non-subscription	O
card	O
for	O
public	O
service	O
broadcast	O
channels	O
Channel	O
4	O
and	O
Channel	O
5	O
,	O
however	O
Channel	O
4	O
London	O
,	O
Film4	O
,	O
Film4+1	O
are	O
free-to-air	O
.	O
</s>
<s>
In	O
September	O
2005	O
,	O
the	O
BBC	O
and	O
ITV	O
announced	O
a	O
free-to-air	O
satellite	B-Application
service	O
as	O
a	O
competitor	O
to	O
Freesat	B-Application
from	I-Application
Sky	I-Application
,	O
to	O
be	O
called	O
Freesat	O
.	O
</s>
<s>
Launched	O
in	O
May	O
2008	O
,	O
Freesat	O
offers	O
all	O
BBC	O
and	O
ITV	O
digital	B-Application
TV	I-Application
channels	O
,	O
plus	O
other	O
channels	O
,	O
interactive	O
services	O
,	O
and	O
radio	O
channels	O
,	O
all	O
using	O
existing	O
broadcasts	O
from	O
Astra	O
28.2	O
°E	O
.	O
</s>
<s>
It	O
is	O
being	O
touted	O
as	O
the	O
satellite	B-Application
equivalent	O
to	O
Freeview	B-Device
,	O
especially	O
for	O
areas	O
unable	O
to	O
receive	O
the	O
Freeview	B-Device
DTT	B-Application
service	O
.	O
</s>
<s>
The	O
UK	O
now	O
has	O
3	O
main	O
ways	O
of	O
accessing	O
high	B-Device
definition	I-Device
television	I-Device
channels	O
.	O
</s>
<s>
The	O
BBC	O
has	O
launched	O
its	O
own	O
high-definition	O
service	O
called	O
BBC	O
HD	O
which	O
is	O
currently	O
available	O
via	O
Digital	O
Satellite	B-Application
.	O
</s>
<s>
BBC	O
HD	O
is	O
also	O
available	O
on	O
Virgin	O
Media	O
and	O
Freeview	B-Device
.	O
</s>
<s>
BBC	O
One	O
HD	O
was	O
launched	O
on	O
3	O
November	O
2010	O
on	O
Sky	O
,	O
Virgin	O
,	O
Freesat	O
and	O
Freeview	B-Device
.	O
</s>
<s>
This	O
trial	O
was	O
a	O
Digital	B-Application
Terrestrial	I-Application
trial	O
which	O
broadcast	O
only	O
from	O
the	O
Crystal	O
Palace	O
transmitting	O
station	O
in	O
London	O
.	O
</s>
<s>
Channel	O
4	O
launched	O
a	O
high-definition	O
simulcast	O
,	O
Channel	O
4	O
HD	O
of	O
its	O
main	O
channel	O
on	O
digital	O
satellite	B-Application
on	O
10	O
December	O
2007	O
.	O
</s>
<s>
It	O
also	O
took	O
part	O
in	O
the	O
terrestrial	O
trial	O
mentioned	O
above	O
and	O
launched	O
on	O
Freeview	B-Device
on	O
31	O
March	O
2010	O
.	O
</s>
