Conferencing Modes Overview
Polycom®, Inc. 16
Mixed CP and SVC Conferencing
In a mixed CP (AVC) and SVC conference, AVC-based endpoints and SVC-enabled endpoints can be
supported in the same conference.
In a mixed CP (AVC) and SVC conference, SVC endpoints transmit multiple resolutions and temporal layers
to the Collaboration Server like the SVC-based conferences, while AVC endpoints, for example, send only
one AVC video stream to the Collaboration Server. Other endpoints (also referred to as AVC endpoints as
opposed to SVC endpoints) can send different video protocols, such as H.263. The Collaboration Server
relays SVC-encoded video bit streams to the SVC-enabled endpoints in the conference according to their
request. This enables the video conference layouts to be automatically assembled by the endpoint. AVC
endpoints connected to the conference send a single AVC video bit stream to the Collaboration Server,
which is then transcoded to SVC video streams. SVC-enabled endpoints receive the AVC converted video
bit streams through the Collaboration Server from the AVC endpoints as a single SVC video bit stream.
Alternatively, AVC endpoints receive a single video bit stream with the defined video conference layout from
the Collaboration Server. In this mixed mode conferencing, both SVC and AVC endpoints in the conference
receive the same CP layout.
The following diagram illustrates an example of a mixed CP and SVC conferencing mode:
In this example, an SVC endpoint (1) receives three video streams at different frame rates and resolutions,
and creates the conference layout with the received video streams. The video bit stream that the SVC
endpoint receives from the AVC endpoint (3) is decoded in the Collaboration Server and then encoded into
an SVC bit stream in the required resolution.
Alternatively, an AVC endpoint (4) sends a single resolution video stream to the Collaboration Server. The
Collaboration Server first decodes the SVC bit streams and AVC bit streams, then the Collaboration Server
composes the video layout for the AVC endpoint and sends a single resolution video stream with the video