Polycom RealPresence 800s Administrator's Manual page 34

RealPresence Collaboration Server (RMX) 800s/Virtual Edition Administrator's Guide
SVC video streams and Layouts
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The video streams displayed in the conference layout on each endpoint is obtained from the different
streams received from each of the endpoints displayed in the layout. Depending on the size of the video cell
in the configured layout, the endpoint requests the video stream in the required resolution from the
RealPresence Collaboration Server. The higher the display quality and size, the higher the requested
resolution will be sent to the endpoint. The endpoint creates the displayed layout from the different video
streams it receives.
For instance, an SVC endpoint might want to receive three video streams at different frame rates and
resolutions, and create a conference layout with the received video streams. Each SVC-enabled endpoint
sends encoded SVC bit streams to the MCU to relay to the other SVC-enabled endpoints in the conference.
The endpoints encode the video in multiple resolutions and decodes the multiple video input streams.
For example:
RealPresence mobile client (2) will transmit two resolutions; one that is suited for RealPresence Desktop
client (3) and a second that is suited for two other endpoints: RealPresence Desktop client (4) and (1).
RealPresence Desktop client (1) transmits two resolutions; one that is suited for RealPresence Mobile client
(2) and a second that is suited for RealPresence Desktop client (4).
The MCU determines which of the incoming resolutions to send to each endpoint. It does not perform any
SVC encoding and decoding, or any transcoding of the video streams. The RealPresence Collaboration
Server functions as the multipoint media relay to the endpoints. For voice activated selection of the video
streams, the RealPresence Collaboration Server determines which of the incoming bit streams to send to
each endpoint.
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