Grass Valley NV8500 Series v.3.5 - Manual (Page 92)

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Crosspoints
Pass-Through Audio
See Embedded Group Control on page 35 for more information.
Pass-Through Audio
When a router configuration includes “pass-through” audio sources, control panel operators can
route the embedded audio from a standard video input to a hybrid (disembedder/embedder)
output directly and with little effort.
Two forms of pass-through audio exist:
• Basic — a single source that governs all 16 audio channels of a video source as a unit.
When a control panel operator specifies the basic audio source, all 16 audio channels of the
disembedder/embedder output are taken from the video routed to that output.
• Extended — defines 16 individual pass-through audio sources, one for each audio output
channel.
When a control panel operator specifies one (or more) of the pass-through audio sources,
the audio source channel specified by the pass-through selection is sent to the selected
audio channel of the output.
For example, if audio source 131 is specified as pass-through channel 3, when a panel opera-
tor “takes” audio port 131 to the output, what happens is that audio channel 3 of the video
routed to the output is taken (or “passed through”) to the chosen audio channel of the out-
put.
The disembedder on the output cards makes those audio channels available. The multi-
plexer on the output card does the individual channel selection.
Note that although pass-through audio sources are called sources, they do not actually carry
audio. They are artificial ports. Using these ports signals to the router’s control card that audio
should be taken from the video at the output.
Nevertheless, the control panel operator treats the pass-through sources as if they were actual
sources, but knowing that the effect of using a pass-through source is to obtain the audio from
the video already present at the output.
Techniques for configuring and using pass-through audio are discussed under Configuring Pass-
Through on page 78.