Abstract: A centralized multipoint conferencing arrangement uses a combination of multicast and unicast transmissions that is bandwidth efficient. A method of conferencing includes transmitting multimedia streams from endpoint terminals to a central resource such as a multipoint control unit (MCU) using unicast transmission. The multimedia streams are processed in the MCU and transmitted back to the endpoint terminals using multicast transmission. In addition, the MCU transmits other multimedia streams to selected endpoint terminals using unicast transmission. At the selected endpoint terminals, processing of the multimedia streams is inhibited in favor of processing the other multimedia streams.

Abstract: A method and apparatus for continuous presence conferencing is disclosed having voice-activated quadrant selection. A control processor in a multipoint control unit selects and assigns anchored sites to anchored regions of a composite video image. The control processor further selects a switched site according to a selection process and assigns the switched site to a switched region of the composite video image. The selection process for selecting the switched site includes evaluating audio signals received from the conference sites to determine a dominant audio signal and selecting the site associated with the dominant audio signal. A rotating site is selected and is assignable to any of the regions. A video processor processes the video signals according to the composite video image assignments to provide composite video signals for transmission to sites in the conference.