<s>
Digital	B-Application
television	I-Application
(	O
DTV	O
)	O
is	O
the	O
transmission	O
of	O
television	O
signals	O
using	O
digital	O
encoding	O
,	O
in	O
contrast	O
to	O
the	O
earlier	O
analog	O
television	O
technology	O
which	O
used	O
analog	O
signals	O
.	O
</s>
<s>
Modern	O
digital	B-Application
television	I-Application
is	O
transmitted	O
in	O
high-definition	B-Device
television	I-Device
(	O
HDTV	B-Device
)	O
with	O
greater	O
resolution	O
than	O
analog	O
TV	O
.	O
</s>
<s>
It	O
makes	O
more	O
economical	O
use	O
of	O
scarce	O
radio	B-Algorithm
spectrum	I-Algorithm
space	O
;	O
it	O
can	O
transmit	O
up	O
to	O
seven	O
channels	O
in	O
the	O
same	O
bandwidth	B-Algorithm
as	O
a	O
single	O
analog	O
channel	O
,	O
and	O
provides	O
many	O
new	O
features	O
that	O
analog	O
television	O
cannot	O
.	O
</s>
<s>
Different	O
digital	B-Application
television	I-Application
broadcasting	I-Application
standards	O
have	O
been	O
adopted	O
in	O
different	O
parts	O
of	O
the	O
world	O
;	O
below	O
are	O
the	O
more	O
widely	O
used	O
standards	O
:	O
</s>
<s>
Digital	B-Application
Video	I-Application
Broadcasting	I-Application
(	O
DVB	B-Application
)	O
uses	O
coded	B-Protocol
orthogonal	I-Protocol
frequency-division	I-Protocol
multiplexing	I-Protocol
(	O
OFDM	B-Protocol
)	O
modulation	O
and	O
supports	O
hierarchical	O
transmission	O
.	O
</s>
<s>
Advanced	B-Device
Television	I-Device
System	I-Device
Committee	I-Device
(	O
ATSC	B-Device
)	O
standard	O
uses	O
eight-level	O
vestigial	O
sideband	O
(	O
8VSB	B-Device
)	O
for	O
terrestrial	O
broadcasting	O
.	O
</s>
<s>
Integrated	B-Protocol
Services	I-Protocol
Digital	I-Protocol
Broadcasting	I-Protocol
(	O
ISDB	B-Protocol
)	O
is	O
a	O
system	O
designed	O
to	O
provide	O
good	O
reception	O
to	O
fixed	O
receivers	O
and	O
also	O
portable	O
or	O
mobile	O
receivers	O
.	O
</s>
<s>
It	O
utilizes	O
OFDM	B-Protocol
and	O
two-dimensional	O
interleaving	O
.	O
</s>
<s>
It	O
supports	O
hierarchical	O
transmission	O
of	O
up	O
to	O
three	O
layers	O
and	O
uses	O
MPEG-2	B-Algorithm
video	I-Algorithm
and	O
Advanced	B-Application
Audio	I-Application
Coding	I-Application
.	O
</s>
<s>
ISDB-T	B-Application
International	I-Application
is	O
an	O
adaptation	O
of	O
this	O
standard	O
using	O
H.264/MPEG	B-Application
-4	I-Application
AVC	I-Application
,	O
which	O
has	O
been	O
adopted	O
in	O
most	O
of	O
South	O
America	O
and	O
Portuguese-speaking	O
African	O
countries	O
.	O
</s>
<s>
Digital	B-Application
Terrestrial	I-Application
Multimedia	O
Broadcast	O
(	O
DTMB	O
)	O
adopts	O
time-domain	O
synchronous	O
(	O
TDS	O
)	O
OFDM	B-Protocol
technology	O
with	O
a	O
pseudo-random	O
signal	O
frame	O
to	O
serve	O
as	O
the	O
guard	O
interval	O
(	O
GI	O
)	O
of	O
the	O
OFDM	B-Protocol
block	O
and	O
the	O
training	O
symbol	O
.	O
</s>
<s>
Digital	O
Multimedia	O
Broadcasting	O
(	O
DMB	O
)	O
is	O
a	O
digital	O
radio	O
transmission	O
technology	O
developed	O
in	O
South	O
Korea	O
as	O
part	O
of	O
the	O
national	O
information	B-General_Concept
technology	I-General_Concept
project	O
for	O
sending	O
multimedia	O
such	O
as	O
TV	O
,	O
radio	O
and	O
datacasting	O
to	O
mobile	B-Application
devices	I-Application
such	O
as	O
mobile	O
phones	O
,	O
laptops	O
and	O
GPS	O
navigation	O
systems	O
.	O
</s>
<s>
Digital	B-Application
television	I-Application
's	O
roots	O
are	O
tied	O
to	O
the	O
availability	O
of	O
inexpensive	O
,	O
high	O
performance	O
computers	O
.	O
</s>
<s>
It	O
was	O
not	O
until	O
the	O
1990s	O
that	O
digital	B-Application
TV	I-Application
became	O
a	O
real	O
possibility	O
.	O
</s>
<s>
Digital	B-Application
television	I-Application
was	O
previously	O
not	O
practically	O
feasible	O
due	O
to	O
the	O
impractically	O
high	O
bandwidth	B-Algorithm
requirements	O
of	O
uncompressed	B-Device
video	I-Device
,	O
requiring	O
around	O
200Mbit/s	O
for	O
a	O
standard-definition	B-Device
television	I-Device
(	O
SDTV	B-Device
)	O
signal	O
,	O
and	O
over	O
1Gbit/s	O
for	O
high-definition	B-Device
television	I-Device
(	O
HDTV	B-Device
)	O
.	O
</s>
<s>
In	O
the	O
mid-1980s	O
,	O
Toshiba	O
released	O
a	O
television	O
set	O
with	O
digital	O
capabilities	O
,	O
using	O
integrated	O
circuit	O
chips	O
such	O
as	O
a	O
microprocessor	B-Architecture
to	O
convert	O
analog	O
television	O
broadcast	O
signals	O
to	O
digital	O
video	O
signals	O
,	O
enabling	O
features	O
such	O
as	O
freezing	O
pictures	O
and	O
showing	O
two	O
channels	O
at	O
once	O
.	O
</s>
<s>
However	O
,	O
they	O
still	O
relied	O
on	O
analog	O
TV	O
broadcast	O
signals	O
,	O
with	O
true	O
digital	B-Application
TV	I-Application
broadcasts	O
not	O
yet	O
being	O
available	O
at	O
the	O
time	O
.	O
</s>
<s>
A	O
digital	B-Application
TV	I-Application
broadcast	O
service	O
was	O
proposed	O
in	O
1986	O
by	O
Nippon	O
Telegraph	O
and	O
Telephone	O
(	O
NTT	O
)	O
and	O
the	O
Ministry	O
of	O
Posts	O
and	O
Telecommunication	O
(	O
MPT	O
)	O
in	O
Japan	O
,	O
where	O
there	O
were	O
plans	O
to	O
develop	O
an	O
"	O
Integrated	O
Network	O
System	O
"	O
service	O
.	O
</s>
<s>
However	O
,	O
it	O
was	O
not	O
possible	O
to	O
practically	O
implement	O
such	O
a	O
digital	B-Application
TV	I-Application
service	O
until	O
the	O
adoption	O
of	O
motion-compensated	O
DCT	B-General_Concept
video	B-Algorithm
compression	I-Algorithm
formats	I-Algorithm
such	O
as	O
MPEG	O
made	O
it	O
possible	O
in	O
the	O
early	O
1990s	O
.	O
</s>
<s>
In	O
the	O
mid-1980s	O
,	O
as	O
Japanese	O
consumer	O
electronics	O
firms	O
forged	O
ahead	O
with	O
the	O
development	O
of	O
HDTV	B-Device
technology	O
,	O
and	O
as	O
the	O
MUSE	O
analog	O
format	O
was	O
proposed	O
by	O
Japan	O
's	O
public	O
broadcaster	O
NHK	O
as	O
a	O
worldwide	O
standard	O
.	O
</s>
<s>
Between	O
1988	O
and	O
1991	O
,	O
several	O
European	O
organizations	O
were	O
working	O
on	O
DCT-based	O
digital	O
video	B-Algorithm
coding	I-Algorithm
standards	I-Algorithm
for	O
both	O
SDTV	B-Device
and	O
HDTV	B-Device
.	O
</s>
<s>
The	O
EU	O
256	O
project	O
by	O
the	O
CMTT	O
and	O
ETSI	O
,	O
along	O
with	O
research	O
by	O
Italian	O
broadcaster	O
RAI	O
,	O
developed	O
a	O
DCT	B-General_Concept
video	B-Application
codec	I-Application
that	O
broadcast	O
SDTV	B-Device
at	O
34Mbit/s	O
and	O
near-studio-quality	O
HDTV	B-Device
at	O
about	O
70140Mbit/s	O
.	O
</s>
<s>
An	O
American	O
company	O
,	O
General	O
Instrument	O
,	O
also	O
demonstrated	O
the	O
feasibility	O
of	O
a	O
digital	B-Application
television	I-Application
signal	O
in	O
1990	O
.	O
</s>
<s>
First	O
,	O
the	O
Commission	O
declared	O
that	O
the	O
new	O
TV	O
standard	O
must	O
be	O
more	O
than	O
an	O
enhanced	O
analog	O
signal	O
,	O
but	O
be	O
able	O
to	O
provide	O
a	O
genuine	O
HDTV	B-Device
signal	O
with	O
at	O
least	O
twice	O
the	O
resolution	O
of	O
existing	O
television	O
images	O
.	O
</s>
<s>
Then	O
,	O
to	O
ensure	O
that	O
viewers	O
who	O
did	O
not	O
wish	O
to	O
buy	O
a	O
new	O
digital	B-Application
television	I-Application
set	O
could	O
continue	O
to	O
receive	O
conventional	O
television	O
broadcasts	O
,	O
it	O
dictated	O
that	O
the	O
new	O
ATV	O
standard	O
must	O
be	O
capable	O
of	O
being	O
simulcast	O
on	O
different	O
channels	O
.	O
</s>
<s>
This	O
outcome	O
resulted	O
from	O
a	O
dispute	O
between	O
the	O
consumer	O
electronics	O
industry	O
(	O
joined	O
by	O
some	O
broadcasters	O
)	O
and	O
the	O
computer	B-General_Concept
industry	I-General_Concept
(	O
joined	O
by	O
the	O
film	O
industry	O
and	O
some	O
public	O
interest	O
groups	O
)	O
over	O
which	O
of	O
the	O
two	O
scanning	O
processes	O
—	O
interlaced	O
or	O
progressive	B-Device
—	O
is	O
superior	O
.	O
</s>
<s>
Progressive	B-Device
scanning	I-Device
,	O
which	O
is	O
the	O
format	O
used	O
in	O
computers	O
,	O
scans	O
lines	O
in	O
sequences	O
,	O
from	O
top	O
to	O
bottom	O
.	O
</s>
<s>
The	O
computer	B-General_Concept
industry	I-General_Concept
argued	O
that	O
progressive	B-Device
scanning	I-Device
is	O
superior	O
because	O
it	O
does	O
not	O
flicker	B-General_Concept
in	O
the	O
manner	O
of	O
interlaced	O
scanning	O
.	O
</s>
<s>
It	O
also	O
argued	O
that	O
progressive	B-Device
scanning	I-Device
enables	O
easier	O
connections	O
with	O
the	O
Internet	O
,	O
and	O
is	O
more	O
cheaply	O
converted	O
to	O
interlaced	O
formats	O
than	O
vice	O
versa	O
.	O
</s>
<s>
The	O
film	O
industry	O
also	O
supported	O
progressive	B-Device
scanning	I-Device
because	O
it	O
offers	O
a	O
more	O
efficient	O
means	O
of	O
converting	O
filmed	O
programming	O
into	O
digital	O
formats	O
.	O
</s>
<s>
For	O
their	O
part	O
,	O
the	O
consumer	O
electronics	O
industry	O
and	O
broadcasters	O
argued	O
that	O
interlaced	O
scanning	O
was	O
the	O
only	O
technology	O
that	O
could	O
transmit	O
the	O
highest	O
quality	O
pictures	O
then	O
(	O
and	O
currently	O
)	O
feasible	O
,	O
i.e.	O
,	O
1,080	O
lines	O
per	O
picture	O
and	O
1,920	O
pixels	B-Algorithm
per	O
line	O
.	O
</s>
<s>
Broadcasters	O
also	O
favored	O
interlaced	O
scanning	O
because	O
their	O
vast	O
archive	O
of	O
interlaced	O
programming	O
is	O
not	O
readily	O
compatible	O
with	O
a	O
progressive	B-Device
format	O
.	O
</s>
<s>
DirecTV	O
in	O
the	O
US	O
launched	O
the	O
first	O
commercial	O
digital	O
satellite	O
platform	O
in	O
May	O
1994	O
,	O
using	O
the	O
Digital	B-Device
Satellite	I-Device
System	I-Device
(	O
DSS	O
)	O
standard	O
.	O
</s>
<s>
Digital	B-Device
cable	I-Device
broadcasts	O
were	O
tested	O
and	O
launched	O
in	O
the	O
US	O
in	O
1996	O
by	O
TCI	O
and	O
Time	O
Warner	O
.	O
</s>
<s>
The	O
first	O
digital	B-Application
terrestrial	I-Application
platform	O
was	O
launched	O
in	O
November	O
1998	O
as	O
ONdigital	O
in	O
the	O
UK	O
,	O
using	O
the	O
DVB-T	O
standard	O
.	O
</s>
<s>
Digital	B-Application
television	I-Application
supports	O
many	O
different	O
picture	O
formats	O
defined	O
by	O
the	O
broadcast	O
television	O
systems	O
which	O
are	O
a	O
combination	O
of	O
size	O
and	O
aspect	O
ratio	O
(	O
width	O
to	O
height	O
ratio	O
)	O
.	O
</s>
<s>
With	O
digital	B-Application
terrestrial	I-Application
television	I-Application
(	O
DTT	O
)	O
broadcasting	O
,	O
the	O
range	O
of	O
formats	O
can	O
be	O
broadly	O
divided	O
into	O
two	O
categories	O
:	O
high-definition	B-Device
television	I-Device
(	O
HDTV	B-Device
)	O
for	O
the	O
transmission	O
of	O
high-definition	O
video	O
and	O
standard-definition	B-Device
television	I-Device
(	O
SDTV	B-Device
)	O
.	O
</s>
<s>
One	O
of	O
several	O
different	O
HDTV	B-Device
formats	O
that	O
can	O
be	O
transmitted	O
over	O
DTV	O
is	O
:	O
pixels	B-Algorithm
in	O
progressive	B-Device
scan	I-Device
mode	O
(	O
abbreviated	O
720p	O
)	O
or	O
pixels	B-Algorithm
in	O
interlaced	O
video	O
mode	O
(	O
1080i	O
)	O
.	O
</s>
<s>
HDTV	B-Device
cannot	O
be	O
transmitted	O
over	O
analog	O
television	O
channels	O
because	O
of	O
channel	O
capacity	O
issues	O
.	O
</s>
<s>
SDTV	B-Device
,	O
by	O
comparison	O
,	O
may	O
use	O
one	O
of	O
several	O
different	O
formats	O
taking	O
the	O
form	O
of	O
various	O
aspect	O
ratios	O
depending	O
on	O
the	O
technology	O
used	O
in	O
the	O
country	O
of	O
broadcast	O
.	O
</s>
<s>
NTSC	O
can	O
deliver	O
a	O
resolution	O
in	O
4:3	O
and	O
in	O
16:9	O
,	O
while	O
PAL	B-Language
can	O
give	O
in	O
4:3	O
and	O
in	O
16:9	O
.	O
</s>
<s>
However	O
,	O
broadcasters	O
may	O
choose	O
to	O
reduce	O
these	O
resolutions	O
to	O
reduce	O
bit	O
rate	O
(	O
e.g.	O
,	O
many	O
DVB-T	O
channels	O
in	O
the	O
UK	O
use	O
a	O
horizontal	O
resolution	O
of	O
544	O
or	O
704	O
pixels	B-Algorithm
per	O
line	O
)	O
.	O
</s>
<s>
Each	O
commercial	O
broadcasting	O
terrestrial	O
television	O
DTV	O
channel	O
in	O
North	O
America	O
is	O
allocated	O
enough	O
bandwidth	B-Algorithm
to	O
broadcast	O
up	O
to	O
19	O
megabits	O
per	O
second	O
.	O
</s>
<s>
However	O
,	O
the	O
broadcaster	O
does	O
not	O
need	O
to	O
use	O
this	O
entire	O
bandwidth	B-Algorithm
for	O
just	O
one	O
broadcast	O
channel	O
.	O
</s>
<s>
Instead	O
,	O
the	O
broadcast	O
can	O
use	O
Program	B-Device
and	I-Device
System	I-Device
Information	I-Device
Protocol	I-Device
and	O
subdivide	O
across	O
several	O
video	O
subchannels	B-Device
(	O
a.k.a.	O
</s>
<s>
A	O
broadcaster	O
may	O
opt	O
to	O
use	O
a	O
standard-definition	B-Device
(	O
SDTV	B-Device
)	O
digital	O
signal	O
instead	O
of	O
an	O
HDTV	B-Device
signal	O
,	O
because	O
current	O
convention	O
allows	O
the	O
bandwidth	B-Algorithm
of	O
a	O
DTV	O
channel	O
(	O
or	O
"	O
multiplex	B-Device
"	O
)	O
to	O
be	O
subdivided	O
into	O
multiple	O
digital	B-Device
subchannels	I-Device
,	O
(	O
similar	O
to	O
what	O
most	O
FM	O
radio	O
stations	O
offer	O
with	O
HD	O
Radio	O
)	O
,	O
providing	O
multiple	O
feeds	O
of	O
entirely	O
different	O
television	O
programming	O
on	O
the	O
same	O
channel	O
.	O
</s>
<s>
This	O
ability	O
to	O
provide	O
either	O
a	O
single	O
HDTV	B-Device
feed	O
or	O
multiple	O
lower-resolution	O
feeds	O
is	O
often	O
referred	O
to	O
as	O
distributing	O
one	O
's	O
bit	O
budget	O
or	O
multicasting	O
.	O
</s>
<s>
With	O
some	O
implementations	O
,	O
image	O
resolution	O
may	O
be	O
less	O
directly	O
limited	O
by	O
bandwidth	B-Algorithm
;	O
for	O
example	O
in	O
DVB-T	O
,	O
broadcasters	O
can	O
choose	O
from	O
several	O
different	O
modulation	O
schemes	O
,	O
giving	O
them	O
the	O
option	O
to	O
reduce	O
the	O
transmission	O
bit	O
rate	O
and	O
make	O
reception	O
easier	O
for	O
more	O
distant	O
or	O
mobile	O
viewers	O
.	O
</s>
<s>
There	O
are	O
several	O
different	O
ways	O
to	O
receive	O
digital	B-Application
television	I-Application
.	O
</s>
<s>
This	O
delivery	O
method	O
is	O
known	O
as	O
digital	B-Application
terrestrial	I-Application
television	I-Application
(	O
DTT	O
)	O
.	O
</s>
<s>
Other	O
delivery	O
methods	O
include	O
digital	B-Device
cable	I-Device
and	O
digital	O
satellite	O
.	O
</s>
<s>
Other	O
standards	O
,	O
such	O
as	O
digital	O
multimedia	O
broadcasting	O
(	O
DMB	O
)	O
and	O
digital	B-Application
video	I-Application
broadcasting	I-Application
-	O
handheld	B-Application
(	O
DVB-H	O
)	O
,	O
have	O
been	O
devised	O
to	O
allow	O
handheld	B-Application
devices	I-Application
such	O
as	O
mobile	O
phones	O
to	O
receive	O
TV	O
signals	O
.	O
</s>
<s>
Finally	O
,	O
an	O
alternative	O
way	O
is	O
to	O
receive	O
digital	B-Application
TV	I-Application
signals	O
via	O
the	O
open	O
Internet	O
(	O
Internet	O
television	O
)	O
,	O
whether	O
from	O
a	O
central	O
streaming	O
service	O
or	O
a	O
P2P	O
(	O
peer-to-peer	O
)	O
system	O
.	O
</s>
<s>
Access	O
to	O
encrypted	O
channels	O
can	O
be	O
controlled	O
by	O
a	O
removable	O
card	O
,	O
for	O
example	O
via	O
the	O
Common	B-Device
Interface	I-Device
or	O
CableCard	B-Application
.	O
</s>
<s>
Digital	B-Application
television	I-Application
signals	O
must	O
not	O
interfere	O
with	O
each	O
other	O
,	O
and	O
they	O
must	O
also	O
coexist	O
with	O
analog	O
television	O
until	O
it	O
is	O
phased	O
out	O
.	O
</s>
<s>
Digital	B-Application
TV	I-Application
is	O
more	O
tolerant	O
of	O
interference	O
than	O
analog	O
TV	O
,	O
and	O
this	O
is	O
the	O
reason	O
a	O
smaller	O
range	O
of	O
channels	O
can	O
carry	O
an	O
all-digital	O
set	O
of	O
television	O
stations	O
.	O
</s>
<s>
One	O
can	O
,	O
for	O
example	O
,	O
browse	O
the	O
electronic	B-Device
program	I-Device
guide	I-Device
.	O
</s>
<s>
Some	O
of	O
these	O
systems	O
support	O
video	B-Application
on	I-Application
demand	I-Application
using	O
a	O
communication	O
channel	O
localized	O
to	O
a	O
neighborhood	O
rather	O
than	O
a	O
city	O
(	O
terrestrial	O
)	O
or	O
an	O
even	O
larger	O
area	O
(	O
satellite	O
)	O
.	O
</s>
<s>
1seg	B-Device
(	O
1-segment	O
)	O
is	O
a	O
special	O
form	O
of	O
ISDB	B-Protocol
.	O
</s>
<s>
Twelve	O
are	O
allocated	O
for	O
HDTV	B-Device
and	O
the	O
other	O
for	O
narrow-band	O
receivers	O
such	O
as	O
mobile	O
televisions	O
and	O
cell	O
phones	O
.	O
</s>
<s>
DTV	O
has	O
several	O
advantages	O
over	O
analog	O
TV	O
,	O
the	O
most	O
significant	O
being	O
that	O
digital	O
channels	O
take	O
up	O
less	O
bandwidth	B-Algorithm
,	O
and	O
the	O
bandwidth	B-Algorithm
needs	O
are	O
continuously	O
variable	O
,	O
at	O
a	O
corresponding	O
reduction	O
in	O
image	O
quality	O
depending	O
on	O
the	O
level	O
of	O
compression	O
as	O
well	O
as	O
the	O
resolution	O
of	O
the	O
transmitted	O
image	O
.	O
</s>
<s>
This	O
means	O
that	O
digital	O
broadcasters	O
can	O
provide	O
more	O
digital	O
channels	O
in	O
the	O
same	O
space	O
,	O
provide	O
high-definition	B-Device
television	I-Device
service	O
,	O
or	O
provide	O
other	O
non-television	O
services	O
such	O
as	O
multimedia	O
or	O
interactivity	O
.	O
</s>
<s>
DTV	O
also	O
permits	O
special	O
services	O
such	O
as	O
multiplexing	O
(	O
more	O
than	O
one	O
program	O
on	O
the	O
same	O
channel	O
)	O
,	O
electronic	B-Device
program	I-Device
guides	I-Device
and	O
additional	O
languages	O
(	O
spoken	O
or	O
subtitled	O
)	O
.	O
</s>
<s>
With	O
digital	B-Application
television	I-Application
,	O
the	O
audio	O
and	O
video	O
must	O
be	O
synchronized	O
digitally	O
,	O
so	O
reception	O
of	O
the	O
digital	O
signal	O
must	O
be	O
very	O
nearly	O
complete	O
;	O
otherwise	O
,	O
neither	O
audio	O
nor	O
video	O
will	O
be	O
usable	O
.	O
</s>
<s>
DTV	O
allows	O
up	O
to	O
5	O
audio	O
signal	O
channels	O
plus	O
a	O
subwoofer	B-Application
bass	O
channel	O
,	O
with	O
broadcasts	O
similar	O
in	O
quality	O
to	O
movie	O
theaters	O
and	O
DVDs	O
.	O
</s>
<s>
Digital	B-Application
TV	I-Application
signals	O
require	O
less	O
transmission	O
power	O
than	O
analog	O
TV	O
signals	O
to	O
be	O
broadcast	O
and	O
received	O
satisfactorily	O
.	O
</s>
<s>
DTV	O
images	O
have	O
some	O
picture	O
defects	O
that	O
are	O
not	O
present	O
on	O
analog	O
television	O
or	O
motion	O
picture	O
cinema	O
,	O
because	O
of	O
present-day	O
limitations	O
of	O
bit	O
rate	O
and	O
compression	O
algorithms	O
such	O
as	O
MPEG-2	B-Algorithm
.	O
</s>
<s>
by	O
allowing	O
more	O
compression	B-Algorithm
artifacts	I-Algorithm
during	O
fast	O
motion	O
where	O
the	O
eye	O
cannot	O
track	O
and	O
resolve	O
them	O
as	O
easily	O
and	O
,	O
conversely	O
,	O
minimizing	O
artifacts	B-Algorithm
in	O
still	O
backgrounds	O
that	O
may	O
be	O
closely	O
examined	O
in	O
a	O
scene	O
(	O
since	O
time	O
allows	O
)	O
.	O
</s>
<s>
Broadcast	O
,	O
cable	O
,	O
satellite	O
,	O
and	O
Internet	O
DTV	O
operators	O
control	O
the	O
picture	O
quality	O
of	O
television	O
signal	O
encodes	O
using	O
sophisticated	O
,	O
neuroscience-based	O
algorithms	O
,	O
such	O
as	O
the	O
structural	B-Algorithm
similarity	I-Algorithm
(	O
SSIM	B-Algorithm
)	O
video	O
quality	O
measurement	O
tool	O
,	O
which	O
was	O
accorded	O
each	O
of	O
its	O
inventors	O
a	O
Primetime	O
Emmy	O
because	O
of	O
its	O
global	O
use	O
.	O
</s>
<s>
Another	O
tool	O
,	O
called	O
Visual	O
Information	O
Fidelity	O
(	O
VIF	O
)	O
,	O
is	O
a	O
top-performing	O
algorithm	O
at	O
the	O
core	O
of	O
the	O
Netflix	O
VMAF	B-Algorithm
video	O
quality	O
monitoring	O
system	O
,	O
which	O
accounts	O
for	O
about	O
35%	O
of	O
all	O
US	O
bandwidth	B-Algorithm
consumption	O
.	O
</s>
<s>
The	O
nature	O
of	O
digital	B-Application
TV	I-Application
results	O
in	O
a	O
perfectly	O
decodable	O
video	O
initially	O
,	O
until	O
the	O
receiving	O
equipment	O
starts	O
picking	O
up	O
interference	O
that	O
overpowers	O
the	O
desired	O
signal	O
or	O
if	O
the	O
signal	O
is	O
too	O
weak	O
to	O
decode	O
.	O
</s>
<s>
cable	O
,	O
recorded	O
media	O
)	O
or	O
may	O
purchase	O
set-top	B-Device
converter	I-Device
boxes	I-Device
to	O
tune	O
in	O
the	O
digital	O
signals	O
.	O
</s>
<s>
In	O
the	O
United	O
States	O
,	O
a	O
government-sponsored	O
coupon	O
was	O
available	O
to	O
offset	O
the	O
cost	O
of	O
an	O
external	O
converter	B-Device
box	I-Device
.	O
</s>
<s>
Prior	O
to	O
the	O
conversion	O
to	O
digital	B-Application
TV	I-Application
,	O
analog	O
television	O
broadcast	O
audio	O
for	O
TV	O
channels	O
on	O
a	O
separate	O
FM	O
carrier	O
signal	O
from	O
the	O
video	O
signal	O
.	O
</s>
<s>
However	O
,	O
after	O
the	O
transition	O
of	O
many	O
countries	O
to	O
digital	B-Application
TV	I-Application
,	O
no	O
portable	O
radio	O
manufacturer	O
has	O
yet	O
developed	O
an	O
alternative	O
method	O
for	O
portable	O
radios	O
to	O
play	O
just	O
the	O
audio	O
signal	O
of	O
digital	B-Application
TV	I-Application
channels	O
;	O
DTV	O
radio	O
is	O
not	O
the	O
same	O
thing	O
.	O
</s>
<s>
The	O
adoption	O
of	O
a	O
broadcast	O
standard	O
incompatible	O
with	O
existing	O
analog	O
receivers	O
has	O
created	O
the	O
problem	O
of	O
large	O
numbers	O
of	O
analog	O
receivers	O
being	O
discarded	O
during	O
digital	B-Application
television	I-Application
transition	O
.	O
</s>
<s>
In	O
2009	O
,	O
an	O
estimated	O
99	O
million	O
analog	O
TV	O
receivers	O
were	O
sitting	O
unused	O
in	O
homes	O
in	O
the	O
US	O
alone	O
and	O
,	O
while	O
some	O
obsolete	O
receivers	O
are	O
being	O
retrofitted	O
with	O
converters	O
,	O
many	O
more	O
are	O
simply	O
dumped	O
in	O
landfills	B-Application
where	O
they	O
represent	O
a	O
source	O
of	O
toxic	O
metals	O
such	O
as	O
lead	O
as	O
well	O
as	O
lesser	O
amounts	O
of	O
materials	O
such	O
as	O
barium	O
,	O
cadmium	O
and	O
chromium	B-Language
.	O
</s>
<s>
According	O
to	O
one	O
campaign	O
group	O
,	O
a	O
CRT	B-Device
computer	B-Device
monitor	I-Device
or	O
TV	O
contains	O
an	O
average	O
of	O
of	O
lead	O
.	O
</s>
<s>
According	O
to	O
another	O
source	O
,	O
the	O
lead	O
in	O
glass	O
of	O
a	O
CRT	B-Device
varies	O
from	O
1.08lb	O
to	O
11.28lb	O
,	O
depending	O
on	O
screen	O
size	O
and	O
type	O
,	O
but	O
the	O
lead	O
is	O
in	O
the	O
form	O
of	O
"	O
stable	O
and	O
immobile	O
"	O
lead	O
oxide	O
mixed	O
into	O
the	O
glass	O
.	O
</s>
<s>
It	O
is	O
claimed	O
that	O
the	O
lead	O
can	O
have	O
long-term	O
negative	O
effects	O
on	O
the	O
environment	O
if	O
dumped	O
as	O
landfill	B-Application
.	O
</s>
<s>
The	O
digital	B-Application
television	I-Application
transition	O
,	O
migration	O
to	O
high-definition	B-Device
television	I-Device
receivers	O
and	O
the	O
replacement	O
of	O
CRTs	O
with	O
flatscreens	O
are	O
all	O
factors	O
in	O
the	O
increasing	O
number	O
of	O
discarded	O
analog	O
CRT-based	O
television	O
receivers	O
.	O
</s>
