Abstract: A multi-point video conference system includes a plurality of CODECs which are set at multiple points and participate in a conference, and a multi-point control unit for transmitting/receiving voice signals and video signals between the CODECs. The multi-point control unit includes level measuring circuits, level adjusting circuits, an audio mixer, and a video signal processing circuit. The level measuring circuits measure the levels of voice signals input from the CODECs. The level adjusting circuits adjust the levels of the voice signals input from the CODECs to substantially the same level on the basis of the measurement results obtained by the level measuring circuits. The audio mixer adds the voice signals output from level adjusting circuits, and outputs a sum voice signal, from which the voice signal corresponding to each of the CODECs at transmission destinations is removed, to each of the CODECs.

Abstract: A plurality of local stations each respectively have terminal equipment for coding in a compressing manner and multiplexing audio data, video data and cnotrol data of the local station to obtain a first multiplex data, and demultiplexing and decoding in a decompressing manner a second multiplex data input thereto from a control station connected by a communication line to the local station. The control station has a multi-point videoconference controller for responding to the control data in the first multiplex data from any local station to process the first multiplex data from a selected station, to generate the second multiplex data to be transmitted to each of other local stations than the selected station. The second multiplex data to the other local stations includes the audio data and the video data in the first multiplex data from the selected station.

Abstract: A multipoint video conference system includes a plurality of conference terminals, placed at remote points in correspondence with participants in a conference, for transmitting/receiving speech and image signals from/to the participants, and a video conference controller for transmitting/receiving speech and image signals to/from the conference terminals. The video conference controller includes an audio mixer, an identifying section, a frame selecting section, and multiplexers. The audio mixer forms a synthetic speech signal by synthesizing speech signals from the conference terminals. The identifying section detects speech signals from the conference terminals and identifies the conference terminal through which the participant has made utterance. The frame selecting section forms a multi-image signal by selecting image signals equal in number to multiple frames from the image signals from the conference terminals on the basis of the identification result obtained by the identifying section.

Abstract: In a multi-point video conference control apparatus, a chairman demultiplexer separates video and speech signals from a multiplexed signal from a chairman CODEC. A talker demultiplexer separates video and speech signals from a selected multiplexed signal. A detecting section detects a talk request signal. A first selection instructing section instructs a first selector to select one multiplexed signal on the basis of a detected talk request signal. A second selection instructing section instructs an image selector to select the video signal from the talker demultiplexer upon detection of no talk request signal, and instructs the image selector to select the video signal from the chairman demultiplexer upon detection of no talk request signal. A multi-address calling multiplexer multiplexes the video signal from the image selector and the speech signal from a speech adder.