Understanding Virtual Channel Types - Polycom SoundStructure C16 Design Manual

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Note: Case-Sensitive Virtual Channel Names
The Virtual channel name is case-sensitive: "Podium Mic" and "PODIUM mic"
would represent two different virtual channels.
The motivation for using virtual channels is both to allow the control system programming to start before the
physical wiring may be known and to make the control system programming re-usable across different
installations regardless of how the system is wired. Virtual channels allow third-party control system code
to be easily re-used because the controller code controls the SoundStructure devices through the virtual
channel names, not the underlying physical input and output that a particular channel is connected to.
Virtual channels make the solution more portable and reusable because the control system doesn't need to
know which physical input or output the signal is connected to, it only needs to know the virtual channel
name. The use of virtual channels should also improve the quality of the control system code since it is more
difficult to confuse "Podium mic" vs. "VCR audio" in the code than it would be to confuse input 7 on device
2 vs. input 9 on device 1. The clarity and transparency of the virtual channel names should reduce the
amount of debugging and subsequently reduce the amount of time to provide a fully functional solution.
For instance, if a virtual channel were called "Podium mic" then the control system code would control this
channel by sending commands to "Podium mic". It would not matter to the control system if on one
installation "Podium mic" were wired to input 1 and on another installation "Podium mic" was wired to input
7. The same control system code can be used on both installations because the SoundStructure devices
would know which underlying physical channel(s) are part of the virtual channel definition. By using the
same API commands on different installations that refer to "Podium mic", the control system code is
insulated from the actual physical connections which are likely to change from one installation to the next.
Note: Virtual Channels Controlling and Configuring Physical Channels
Virtual channels are a high-level representation that encompasses information
about the physical channel and are used to configure and control the underlying
physical channel(s) without having to know which physical input or output the virtual
channel is connected to after the virtual channel has been defined.
Within SoundStructure Studio and any third-party controller code, virtual channels are the only way to
configure and control the underlying physical channels. The physical input and output channel numbering
described in the previous section is used only in the definition of virtual channels so that the virtual channel
knows which physical channel(s) it refers to.
A benefit of working with virtual channels is that stereo signals can be more easily used and configured in
the system without having to manually configure both the left and right channels independently. Using virtual
channels that represent stereo physical signals reduces the chance of improper signal routings and
processing selections. The result is that both designs and installations can happen faster and with higher
quality.

Understanding Virtual Channel Types

Virtual channels are operated on by the command set which can apply parameter changes to the underlying
physical channels. For example, setting the fader parameter of a virtual channel would set the fader
parameter for its underlying physical channels.
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