Definition
Audio conferencing allows participants in a live session to hear each other.
The audio is transmitted over the network between users, live and in real-time. Audio conferencing is one component of teleconferencing; the others are video conferencing, and data conferencing. Since the audio 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 G.711 [2] audio codec, which is basically uncompressed 8-bit PCM signal at 8 KHz in either A-Law or A-Law format, must be supported. This leads to bitrates of 56 or 64 Kbps, which are relatively high for audio but supported by today's networks.
Support for other ITU-T audio recommendations and compression is optional, and its implementation specifics depend on the required speech quality, bit rate, computational power, and delay. Provisions for asymmetric operation of audio codecs have also been made;...
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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 G.711 Recommendation – Pulse code modulation (PCM) of voice frequencies, November 1988.
International Telecommunication Union, Telecommunication Standardization Sector G.723.1 Recommendation – Dual rate speech coder for multimedia communications transmitting at 5.3 and 6.3 Kbit/s, March 1996.
International Telecommunication Union, Telecommunication Standardization Sector G.729 Recommendation – Coding of speech at 8 Kbit/s using conjugate-structure algebraic-code-excited linear-prediction (CS-ACELP), March 1996.
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). Audio Conferencing. In: Furht, B. (eds) Encyclopedia of Multimedia. Springer, Boston, MA. https://doi.org/10.1007/978-0-387-78414-4_322
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