Kalypso & zodiak contribution tally protocol – Grass Valley Switcher Products User Manual
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Switcher Products — Protocols Manual
Section 1 — Tally Protocol
Number of Data Bits: must be 8
Number of Stop Bits: 1 (typical) or 2.
The semicolon indicates a comment separator causing the rest of the line to
be ignored by the parser.
Kalypso & Zodiak Contribution Tally Protocol
Contribution tally makes it possible to determine which sources and pro-
cessing blocks (an ME or DVE) contribute to the image at any point in the
video path. On-air tally, for example identifies which sources contribute in
some way to the main program output of the switcher. ME 2 iso tally starts
at ME 2’s main program output.
Refer to Tally Calculation Basics
for
more details.
Contribution tally consists of approximately 220 bytes of information.
Because bandwidth is limited to approximately 128 bytes per field at
76.8 kb, this information is broken into smaller messages. This allows
sending changes at a higher priority than unchanging information. Even
with prioritized updates, there is no guarantee that all changes will be com-
municated within one field. See
for specific timing
information.
Contribution messages indicate which sources are selected on buses
feeding the processing block (or output) and which of those inputs con-
tribute to a processing block’s output. In the cases where a processing block
has several outputs, a separate contribution map is included for each
output. Contribution tally for external processing blocks such as a DVE also
lists the source IDs for this block’s output(s) so that reentry paths through
external devices can be identified and followed.
Contribution message codes start at 0x8 with an instance ID grater than or
equal to one. This insures that command character value is always above
128 so it is recognized as a command code. Command codes 0xE and 0xF
are not used but are reserved.
Contribution information for each processing block is sent as a separate
message. Information for switcher outputs is sent in six messages of eight
outputs each. All portions of the system are included in the contribution
dump even if they are inactive. Inactive blocks will contain data which
indicates inactive status for all inputs to the processing block. In addition,
that block’s outputs will never appear as selections on any bus of the
switcher.