| 摘要 |
<p>Video compression technology is used to convert the digital video output (DV-stream) into files at least ten times smaller than the equivalent uncompressed files, allowing video conferencing to take place over lines with a speed less than 1 Mbit/s, e.g. a PODSL line with a speed from 256 kbit/s up to 1 Mbit/s. This is achieved using a specially developed MPEG-4 video conferencing code (vico) for reducing an MPEG-2 file to an MPEG-4 file, corresponding to a compression ratio of 12:1, ie a compression of an MPEG-2 file from 7 Gb to 450 Mb. The center contains at least one sealed off (e.g. acoustically insulated) room connected to one or more additional centers via one or more secure priority lines (e.g. via an effective intranet, virtual intranet or extranet) or non-secure lines (e.g. Internet connection via computer, hand-held device or cable TV). Access to the center, rooms and/or facilities is restricted to identified members, customers or visitors. The conference room contains at least one display system (e.g. a monitor screen, wall display, LCD screen), at least one optionally concealed image capture system (e.g. digital video camera or webcam) and a connection (wireless or non-wireless) with at least one central computer in the center, a server in the intranetwork and/or a computer in the room. Video conferencing software is provided for allowing control of the session from a central computer and/or a local computer in the room, e.g. for controlling the screen display quality, positioning, image capture properties, outlook, bringing in new conference correspondents, speak priority, identification, document or file insertion, movies, presentation, line priority, number of frames, cameras or conference duration.</p> |
