
to both the serial standard and the associated parallel
standards.
This standard first explains the structure of the pro-
posed 4-byte payload identifier. It then defines how
the payload identifier is placed in an ancillary data
packet according to SMPTE 291M. The last clause
will define the position and timing of the ancillary data
packet for various interfaces.
Annex A defines the payload identifier values for the
following interfaces:
– SMPTE 259M and ITU-R BT.656 (525/625-line
interlaced scanning at 270/360 Mb/s);
– ITU-R BT.1358 and ITU-R BT.1362 (525/625-line
progressive scanning, dual-link at 270 Mb/s and
single link at 360 Mb/s);
– SMPTE 347M (525/625-line interlaced and pro-
gressive scanning modes at 540 Mb/s);
– SMPTE 296M and SMPTE 292M (720-line pro-
gressive scanning at 1.485 Gb/s);
– SMPTE 274M, SMPTE RP 211, and SMPTE
292M (1080-line interlaced, progressive, and seg-
mented frame scanning modes at 1.485 Gb/s);
– SMPTE 349M and SMPTE 292M (525/625-line
interlaced and progressive scanning modes at
1.485 Gb/s).
NOTE – Segmented frame scanning has the full name
progressive segmented frame and uses the acronym
PsF in this standard.
Annex B shows the mapping of the payload identifier
from the ancillary packet data structure of SMPTE
292M to the K-L-V data structure of SMPTE 336M.
The 4-byte payload identifier is an item of metadata
which can be registered in the SMPTE metadata
dictionary (SMPTE RP 210).
Annex C explains why a payload identifier is needed
for digital video interfaces and why the identifier is 4
bytes in length.
4 Payload identifier
The payload identifier shall be used to identify the
video payload carried on a digital television bit serial
interface.
The payload identifier shall be 4 bytes long where
each byte has a separate significance. The first byte
of the payload identifier shall have the highest signifi-
cance and subsequent bytes shall define lower order
video payload information. A precise definition of each
payload identifier shall be provided for each interface
based on the following guidelines:
4.1 Byte 1: Video payload standard
This first byte has the highest significance and shall
be used to identify the combination of digital television
sampling standard and serial digital interface stand-
ard (SDI).
Note that some SDI transports can carry a number of
different video payload types at the same bit rate by
changing the timing and repetition rates of the timing
reference signals. Furthermore, video payloads can
now be mapped onto several SDI transports. Thus, the
first byte identifies both the video payload itself and the
SDI transport onto which the payload is mapped.
The first byte of the payload identifier shall have a
nonzero value for all valid video payloads. Thus, the
first byte can be used to address up to 255 valid video
payload standards.
4.2 Byte 2: Video payload frame rate and line
scanning
The second byte shall be used to identify the video
payload frame rate and, where necessary, the line
scanning format.
For all video payloads on SDI transports, bits b3 to b0
of byte 2 shall be reserved to define the video frame
rate in hertz. The 4 bits allow values of 0
h
to F
h
which
shall be as defined in table 1.
Bits b7 and b4 are used as defined by the application.
The default value of these bits shall be 0.
4.3 Byte 3: Sampling structures
The third byte shall be used to identify aspects of the
sampling structure of the payload.
For all video payloads on SDI transports, bits b3 to b0
of byte 3 shall be reserved to identify the horizontal
sampling structure. The 4 bits allow values of 0
h
to F
h
which shall be as defined in table 2.
SMPTE 352M-2001
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