<s>
CTA-708	B-Device
(	O
formerly	O
EIA-708	B-Device
and	O
CEA-708	B-Device
)	O
is	O
the	O
standard	O
for	O
closed	O
captioning	O
for	O
ATSC	B-Device
digital	B-Application
television	I-Application
(	O
DTV	O
)	O
streams	O
in	O
the	O
United	O
States	O
and	O
Canada	O
.	O
</s>
<s>
Unlike	O
RLE	B-Algorithm
DVB	B-Application
and	O
DVD	O
subtitles	O
,	O
CTA-708	B-Device
captions	O
are	O
low	O
bandwidth	O
and	O
textual	O
like	O
traditional	O
EIA-608	O
captions	O
and	O
EBU	O
Teletext	O
subtitles	O
.	O
</s>
<s>
However	O
,	O
unlike	O
EIA-608	O
byte	O
pairs	O
,	O
CTA-708	B-Device
captions	O
are	O
not	O
able	O
to	O
be	O
modulated	O
on	O
an	O
ATSC	B-Device
receiver	O
's	O
NTSC	O
VBI	O
line	O
21	O
composite	O
output	O
and	O
must	O
be	O
pre-rendered	O
by	O
the	O
receiver	O
with	O
the	O
digital	O
video	O
frames	O
,	O
they	O
also	O
include	O
more	O
of	O
the	O
Latin-1	O
character	O
set	O
,	O
and	O
include	O
stubs	O
to	O
support	O
full	O
UTF-32	O
captions	O
,	O
and	O
downloadable	O
fonts	O
.	O
</s>
<s>
CTA-708	B-Device
caption	O
streams	O
can	O
also	O
optionally	O
encapsulate	O
EIA-608	O
byte	O
pairs	O
internally	O
,	O
a	O
fairly	O
common	O
usage	O
.	O
</s>
<s>
CTA-708	B-Device
captions	O
are	O
injected	O
into	O
MPEG-2	B-Algorithm
video	O
streams	O
in	O
the	O
picture	B-Device
user	I-Device
data	I-Device
.	O
</s>
<s>
It	O
is	O
a	O
fixed-bandwidth	O
channel	O
that	O
has	O
960	O
bit/s	O
typically	O
allocated	O
for	O
backward	O
compatible	O
"	O
encapsulated	O
"	O
Line	O
21	O
captions	O
,	O
and	O
8640	O
bit/s	O
allocated	O
for	O
CTA-708	B-Device
captions	O
,	O
for	O
a	O
total	O
of	O
9600	O
bit/s	O
.	O
</s>
<s>
CTA-708	B-Device
caption	O
decoders	O
are	O
required	O
in	O
the	O
U.S.	O
by	O
FCC	O
regulation	O
in	O
all	O
diagonal	O
or	O
larger	O
digital	B-Application
televisions	I-Application
.	O
</s>
