GRASS VALLEY NV8500 Series, User Manual

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NV8500 Series
User’s Guide
Dolby E signal is off-rate, the router adds or drops samples in the Dolby E guard band to main-
tain Dolby signal integrity.
Hybrid I/O cards require the installation of hybrid control cards and hybrid crosspoint cards in
the router.
Embedder State for Embedder Output Cards
Embedders can receive video and audio from a standard video input card. In such a case, the
embedder card passes the video and audio unmodified through to output,
bypassing the
embedder for that output. In such a case, we say the embedder is “off.”
However, when the embedder receives audio from (one or more) audio sources such as a disem-
bedder card or a MADI input card, the embedder passes the audio from the TDM matrix to the
embedder which multiplexes the different audio streams into its video output. In this case, we
say the embedder is “on.”
The router turns an output’s embedder on or off automatically according to switching rules . (See
Switching Rules on page 80). However, every input has a “force” attribute (that can be set in
MRC).
When the “force” attribute is ON, the output’s embedder is forced on.
When the “force” attribute is “Use Switching Rules,” the output’s embedder is not forced, but left
in its automatically generated state.
Note: This attribute is specified in MRC’s ‘Input Attributes’ page.
Note: if your router uses DHP, the setting for all inputs should be “Use Switching Rules.”
State of Disembedder/Embedder Output Cards
The disembedder/embedder output card has a disembedder and 16 audio multiplexers, in addi-
tion to the embedder, for each output. Router logic can select for each audio channel of each
output one of the following sources: (1) the equivalent audio channel from the video at the
output, (2) generated silence, or (3) audio from other sources, via the TDM audio matrix.
Each multiplexer is controlled by its audio channel’s ‘null’ flag and ‘pass-through’ flag. If the ‘null’
flag is set, the channel is null. The channel carries silence unless all 4 channels in a group are null,
in which case, the entire group is omitted from the output.
If the channel is not null, it receives audio from the same channel of the video at the output if its
pass-through flag is set. Otherwise, it receives audio from another source through the TDM
matrix.
 Embedders of disembedder/embedder output cards are not affected by the “force” attribute
as are the embedders of embedder cards. The embedders of disembedder/embedder cards
are always on.
 The use of pass-through audio is not compatible with DHP. Thus, disembedder/embedder
output cards are not compatible with DHP.
Combining Standard and Hybrid
DHP (dynamic hybrid pathfinding) is an NV9000 service that allows NV8500 series routers to
disembed and embed audio signals in video streams with relatively few hybrid 3Gig cards
installed. With DHP, the router passes standard 3Gig inputs through an internal pool of disem-