Multipoint control unit

Abstract: A video teleconferencing system uses digital transcoding to obtain algorithm transcoding, transmission rate matching, and spatial mixing. The video teleconferencing system comprises a multipoint control unit (MCU) for allowing multiple audiovisual terminals, which send and receive compressed digital data signals, to communicate with each other in a conference. The MCU has a video processing unit (VPU) that performs algorithm transcoding, rate matching, and spatial mixing among the terminals within a conference. The VPU includes a time division multiplex pixel bus and a plurality of processors. Each processor is assignable to an audiovisual terminal in the conference and is coupled to the pixel bus. In a receive mode, each processor receives and decodes compressed video signals from its assigned terminal and puts the decoded signal onto the pixel bus. In a transmit mode, each processor receives from the pixel bus uncompressed video signals from any terminal in the conference. The uncompressed video signals are processed and encoded for transmission to the respective assigned terminal. Video encoding time due to motion displacement search is reduced by passing displacement information from the compressed video signals to the encoder to be used directly or as a seed for further refinements of the motion displacement field.

Abstract: Real time delivery of multimedia information accessed either through the Internet, or otherwise, simultaneously, or sequentially time delayed to one more users, is enabled by delivering the multimedia information over a switched network via a multipoint control unit A client establishes a connection with a server, or other remote location where desired multimedia information is resident, identifies the desired multimedia information and provides client information identifying the locations of the users The client information may include the telephone numbers or other access numbers of each of the multiple users The multimedia information is then delivered by a multimedia server to a bridging apparatus through a switched network guaranteeing high quality of service, secure connection and billing control Connecting one or more users to a live agent is also made possible by providing the telephone numbers of the users and the live agent directly to the multipoint control unit The delivery of the multimedia information can be secured by comparing the client information to a segmented "to call" list to determine whether the client is authorized to receive the requested multimedia information Alternatively, or in addition, security can be implemented by mounting a video camera at the client's endpoint and connecting a database running face recognition software to the multimedia server The multimedia server's call to the user triggers the camera to take a picture of the user The selected content is restricted to authorized users by comparing the picture to pictures of authorized faces stored in the database

Abstract: A multipoint control unit (MCU) or other digital video-processing apparatus operates to manipulate compressed digital video from several compressed digital video sources. The apparatus has a plurality of video input modules and a plurality of video output module. Each of the video input modules receives a compressed video signal from one of the sources and generally decodes the data into a primary data stream and a secondary data stream. The video output module receives the primary and secondary data streams, from at least one of the input module for generally encoding to a compressed output stream for transmission.

Abstract: A method and apparatus of providing a back-channel for a receiver terminal in a loosely-coupled conference is described. The loosely-coupled conference includes at least one receiver terminal and a H.323 panel having a multipoint controller with a multipoint address and one or more H.323 terminals coupled to the multipoint controller and each to transmit and receive media streams on a multicast address. The method includes the steps of receiving media streams of the one or more H.323 terminals on the multicast address by the receiver terminal, connecting to the multipoint controller by using the multipoint address, and joining the H.323 panel to transmit and receive media streams on the multicast address for establishing bi-directional communication with the one or more H.323 terminals.