Service manual

C-2
General on EDH
C
Error Detection and Handling (EDH)
◆
General on EDH
Reference The P
OLARIS
and S
TELLAR
support EDH (Error Detection and Handling) for 625
lines SDI according to SMPTE RP 165.
Background EDH is used for recognizing errors and inaccuracies in the SDI signal. You may use
EDH as a tool to help pinpointing sources of errors in a chain of SDI equipment,
including video codecs with SDI interfaces.
Conceptually, the P
OLARIS
and the S
TELLAR
is one EDH entity.
The P
OLARIS
analyzes the EDH data from the SDI input, and checks for CRC errors.
The flags are manipulated, if necessary. The EDH data is then transmitted in the TS.
The S
TELLAR
outputs the EDH data it receives. Alternatively, if the codec is the first
“EDH node” in an installation, the user may wish to let the S
TELLAR
output EDH
data with all flags cleared. This feature is supported by the S
TELLAR
.
EDH flags EDH includes the following flags for each field:
• IDH Internal error Detected Here
• IDA Internal error Detected Already
• EDH Error Detected Here
• EDA Error Detected Already
• UES Unknown Error Status
Picture groups There are three picture groups, that each includes the above flags:
• ANC (ANCillary data)
• AP (Active Picture)
• FF (Full Field)
P
OLARIS
and S
TELLAR
behavior
All flags for all groups are supported by the P
OLARIS
and S
TELLAR
. However, detec-
tion of internal errors in the sense of EDH is not supported. Therefore, the codec
never sets the IDH flags, but always clears the IDH flags, and only uses the status of
the incoming IDH flags to influence the status of the outgoing IDA flags.
References The P
OLARIS
Multichannel Encoder, Operator and service manual, order no. 983743,
explains the EDH flags in details.
BARCO data
broadcasting ID
The EDH data between the encoder and decoder is sent as BARCO data broadcasting
sub_id 0x01.
POLARIS Multichannel MPEG-2 Encoder
STELLAR MPEG-2 Decoder
SDI input
Transport stream
SDI output
EDH entity