GRASS VALLEY NV8500 Series, User Manual

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Crosspoints
Switching Rules
The general procedure for performing pass-through takes (with shuffle) is:
1 Selects a destination.
2 Select a destination level (say Audio 3).
3 Choose a pass-through source (say Pass12).
(Taking pass12 to audio 3 of the destination means that audio channel 12 of the video at the
input is taken to audio channel 3 of the output.)
4 Repeat steps 2 and 3 for any other portions of the overall audio shuffle you want to achieve.
5 Press ‘Take’.
This method gives operators independent control of all pass-through channels (or as many
pass-through channels as you want your system to have).
Notes
When the router detects that the pass-through source was selected, it does not route audio
from the pass-through source, but sets the pass-through flags for the chosen audio levels. Each
flag tells the output to use the corresponding disembedder channel output in the output
stream. Refer to Figure 3-5.

A port designated as the “pass-through source” cannot also be used as a normal source.

“Pass-through” audio is not compatible with DHP.

If a pass-through source is “taken” to an output that is not on a disembedder/embedder
card, the take is rejected (with an error message).
 Only NV8500 family routers (at firmware version 3.3.1 or later) support pass-through audio.
Switching Rules
There are presently 4 aspects involved in what are called “switching rules.”
• Embedded group control (and “null” audio).
• Pass-through audio.
• Obsolete ‘AFV’ partition.
• Input attribute — force embedder on.
• Tally — effective status versus actual status.
AFV Partition
The routers’ switching rules accommodate ‘AFV’ partitions, but AFV partitions are not supported
by recent releases of MRC.

If your router has an AFV partition and you want to continue to use it, do not delete it. You
cannot recreate it in the newer versions of MRC.
Force Embedder On
MRC allows you to specify a “force embedder on” attribute for any and all inputs. When the
attribute is off, the output embedder obeys general switching rules. When the attribute is on,
the embedder is forced on, regardless of other factors.