<s>
In	O
television	O
technology	O
,	O
Error	B-Device
Detection	I-Device
and	I-Device
Handling	I-Device
(	O
EDH	O
)	O
protocol	O
is	O
an	O
optional	O
but	O
commonly	O
used	O
addition	O
to	O
the	O
Standard	O
Definition-Serial	O
Digital	O
Interface	O
(	O
SDI	O
)	O
standard	O
.	O
</s>
<s>
This	O
protocol	O
allows	O
an	O
SD-SDI	B-Protocol
receiver	O
to	O
verify	O
that	O
each	O
field	O
of	O
video	O
is	O
received	O
correctly	O
.	O
</s>
<s>
The	O
SD-SDI	B-Protocol
transmitter	O
calculates	O
two	O
CRC	O
values	O
for	O
each	O
video	O
field	O
—	O
one	O
corresponding	O
to	O
the	O
active	O
picture	O
,	O
and	O
corresponding	O
to	O
the	O
entire	O
field	O
(	O
excluding	O
the	O
switching	O
lines	O
)	O
--and	O
places	O
them	O
in	O
an	O
EDH	O
ancillary	O
data	O
packet	O
.	O
</s>
<s>
The	O
SD-SDI	B-Protocol
receiver	O
also	O
generates	O
the	O
same	O
two	O
CRC	O
values	O
for	O
each	O
field	O
and	O
compares	O
them	O
against	O
the	O
CRC	O
values	O
in	O
the	O
received	O
EDH	O
packet	O
to	O
determine	O
if	O
each	O
field	O
of	O
video	O
is	O
received	O
without	O
errors	O
.	O
</s>
<s>
The	O
EDH	O
protocol	O
does	O
not	O
provide	O
for	O
error	B-Error_Name
correction	I-Error_Name
,	O
only	O
error	B-Error_Name
detection	I-Error_Name
.	O
</s>
<s>
Also	O
,	O
there	O
is	O
no	O
mechanism	O
in	O
SD-SDI	B-Protocol
to	O
allow	O
a	O
field	O
containing	O
errors	O
to	O
be	O
retransmitted	O
.	O
</s>
<s>
EDH	O
is	O
not	O
used	O
with	O
high	B-Device
definition	I-Device
video	O
,	O
as	O
the	O
HD	O
serial	B-Protocol
digital	I-Protocol
interface	I-Protocol
includes	O
a	O
mandatory	O
embedded	O
CRC	O
for	O
each	O
line	O
.	O
</s>
