Embedded group control – Grass Valley MRC v.1.2 User Manual
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Miranda Router Configurator
User’s Guide
ENDIF -- valid source
ENDIF -- null or not
ENDIF video or audio
IF Flag
bypass embedder and tally effective status
ELSE
use embedder and tally actual status
ENDIF
Notes:
1 The objective of the logic is to determine whether to bypass the embedder and whether to
set the ‘Insert Silence’ flag. The ‘Insert Silence’ flag governs whether the null audio source is
used.
(The ‘Insert Silence’ flag — or ‘null’ flag — is part of the pass-through logic of disembedder/
embedder outputs.
2 The “force embedder” attribute is specified in MRC’s ‘Input Attributes’ page.
3 The embedder of disembedder/embedder output cards is always on and is not bypassed.
The “force embedder” attribute is not used for disembedder/embedder outputs.
Embedded Group Control
SDI video signals can carry up to 16 audio channels. We say the channels are embedded in the
video. The channels are organized into 4 groups of 4 channels each.
An NV8500 router can force embedded audio channels to be null at output. If all 4 channels of
an embedded audio group are null, the group is null too. That is,
If a single channel is null, the output’s embedder inserts silence for that channel.
If all 4 channels of an audio group are null, the embedder will omit the group from its outgoing
data stream.
Routing a null source to an output is under operator control (or under control of automation).
Two conditions are required for the router to be able to do this:
•
In MRC, you must define a “null audio source” for the router.
•
An operator must perform takes of the designated null source(s) to the selected audio chan-
nels of the intended destination.
A “null audio source” can be any of the inputs in a synchronous audio partition of the router. It is
recommended that you use a port number of one of a disembedder card’s unused video ports
(one where the video port number is a multiple of 9). See
Nothing of the audio port’s signal is used. The “null audio source” is an artifice that tells router
firmware to handle the destination’s targeted audio channel(s) in a certain way.
A port designated as the “null audio source” cannot also be used as a normal audio source.
The use of embedded group control is not compatible with DHP.
If a null source is routed to a MADI output, the take is rejected.
Only NV8500 family routers (at firmware version 3.1 or later) support embedded group
control.