GRASS VALLEY NV8500 Series, Руководство пользователя

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35
NV8500 Series
User’s Guide
audio channels 577–640 and 721–784, and so on. Other audio channels in the “space” of the
card
do not exist.
Consecutive MADI output cards increment by 18 video ports and 288 audio channels. Consecu-
tive cards follow the slot ordering for port numbers.
Slot Order for Port Numbering on page 37.
The number scheme for MADI expansion output cards (used by the expanded NV8576-Plus
only) is like the numbering scheme for MADI input cards. (MADI expansion output cards have 8
video outputs and 1 MADI outputs.)
Embedded Group Control
An NV8500 router can force embedded audio channels to be null. 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 null sources 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’s synchronous audio level.
• 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).
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 hybrid routers at v3.1.2 and later support embedded group control.
 In MRC, router levels that are not ‘Synchronous Audio’ do not support null audio sources. In
the ‘Router Levels’ page of MRC, the ‘Null Audio Source’ field for these levels is not enabled.
 Whether an audio channel is null is a factor in the logic of disembedder/embedder output
cards.