Polycom DOC2702A User Manual

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Polycom RealPresence Collaboration Server (RMX) 1500/2000/4000 Administrator’s Guide 
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Polycom, Inc.
SVC-based Conferencing 
The SVC-Based conferencing mode provides video without transcoding by the MCU, hence 
requiring less video resources while providing better error resiliency and lower latency.
Using the SVC video protocol, SVC conferences provide video bit streams at different 
resolutions, frame rates and line rates to SVC-enabled endpoints with various display 
capabilities and layout configurations. 
In the SVC-based conference, each SVC-enabled endpoint transmits multiple bit streams, 
called simulcasting, to the Polycom® RealPresence® Collaboration Server. Simulcasting 
enables each endpoint to transmit at different resolutions and frame rates such as 720p at 
30fps, 15fps, and 7.5fps, 360p at 15fps and 7.5fps, and 180p at 7.5fps. 
The Polycom SVC-enabled endpoints (such as Polycom® RealPresence® Desktop and 
Polycom® RealPresence® Mobile) compose the layout according to their layout settings and 
video capabilities. This enables the MCU to send or relay the selected video streams to each 
endpoint without processing the video streams and sending the composite video layout to 
the endpoints.
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Figure 2-3
SVC video streams and Layouts
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.