Polycom 2000/4000 Benutzerhandbuch

Chapter 2-Additional Conferencing Information

The H.239 protocol allows compliant endpoints to transmit and receive 

two simultaneous video streams:
•

People Conference – Continuous Presence or Video Switched 

conference

•

Content Conference – Video Switching conference for content 

sharing

By default, all conferences, Entry Queues, and Meeting Rooms launched 

on the RMX 2000/RMX 4000 have H.239 capabilities.
To view Content, endpoints must use the same Bit Rate, Protocol, and 

Resolution. An endpoint may not send Content while connecting to an 

Entry Queue.
Endpoints without H.239 capability can connect to the video conference 

without Content.
Cascade links declare H.239 capabilities and they are supported in Star 

and MIH cascading topologies. For more details, see "Cascading 

The Content channel can transmit one of the following modes:
•

Graphics – default mode, for standard graphics

•

Hi-res Graphics – requiring a higher bit rate, for high quality display 

or highly detailed graphics

•

Live Video – highest bit rate, for video clips or live video display

The highest common Content bit rate is calculated for the conference each 

time an endpoint connects. Therefore, if an endpoint connects to an 

ongoing conference at a lower bit rate than the current bit rate, the 

Content bit rate for the current conference is re-calculated and decreased. 
Bit rate allocation by the MCU is dynamic during the conference and 

when the Content channel closes, the video bit rate of the People conference 

is restored to its maximum.
During a conference the MCU will not permit an endpoint to increase its 

bit rate, it can however change its Content resolution. The RMX can 

decrease the allocated Content bit rate during a conference.