Polycom RealPresence Collaboration Server (RMX) 1500/2000/4000 Administrator’s Guide
2-12 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.