Definition
Video conferencing allows participants in a live session to see each other; the video is transmitted over the network between users, live and in real-time.
Video conferencing is one component of teleconferencing, the others are audio conferencing, and data conferencing. Since the video must be encoded, transmitted, and decoded in real-time, special compression and transmission techniques are typically used. In a teleconferencing system that is ITU-T H.323 [1] compliant, the H.261 [2] video codec in its QCIF format must be supported. Support for other H.261 formats or the H.263 [3] codec is optional. During the initial setup, a specific video data rate is selected during the capability exchange. This rate should not be violated throughout the duration of the session. The H.261 standard uses communication channels that are multiples of 64 kbps, known as p × 64, where pε{1,2,3, … 30]. From a video encoding perspective, there are no Bidirectional or “B” frames in H.261....
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References
International Telecommunication Union, Telecommunication Standardization Sector H.323 Recommendation – Packet-based multimedia communications systems, July 2003.
International Telecommunication Union, Telecommunication Standardization Sector H.261 Recommendation – Video codec for audiovisual services at p × 64 kbit/s, March 1993.
International Telecommunication Union, Telecommunication Standardization Sector H.263 Recommendation – Video coding for low bit rate communication, January 2005.
H. Schulzrinne, S. Casner, R. Frederick, and V. Jacobson, “RTP: A Transport Protocol for Real-Time Applications,” IETF RFC 1889, January 1996.
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© 2008 Springer-Verlag
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(2008). Video Conferencing. In: Furht, B. (eds) Encyclopedia of Multimedia. Springer, Boston, MA. https://doi.org/10.1007/978-0-387-78414-4_241
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DOI: https://doi.org/10.1007/978-0-387-78414-4_241
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