What is web conferencing ?
Web conferencing is used to conduct live meetings or presentations over the Internet. In the early years of the Internet, the terms "web conferencing" and "computer conferencing" were often used to refer to group discussions conducted within a message board (via posted text messages) therefore not live, but the term has evolved to refer specifically to "live" or "synchronous" meetings, while the posted message variety of discussion is called a "forum", "message board", or "bulletin board".
In a web conference, each participant sits at their own computer, and is connected to other participants via the internet through an application which a "host" company provides and charges for its use. This can be either a downloaded application on each of the attendees computers or a web-based application where the attendees will simply enter a "URL" or website meeting address to enter the live meeting or conference. These web-based applications are used either with Flash or Java technology.
A webinar is a type of web conference, although the direction of the presentation more often than not is primarily one way from the presenter to the audience as in a Webcast, which is transmission of information in one direction only, like watching a concert on the internet. A webinar however can be designed to be interactive between the presenter and audience. A webinar is 'live' in the sense that information is conveyed according to an agenda, with a starting and ending time. In most cases, the presenter may speak over a standard telephone line, pointing out information being presented on screen, and the audience can respond over their own telephones, preferably a speakerphone. The word 'webinar' is a portmanteau combining the words web and seminar.
Standards
Web conferencing technologies were not standardized for many years, a significant factor in the lack of interoperability, platform dependence, security issues, cost and market segmentation. In 2003, the IETF established a working group to establish a standard for Web conferencing, called XCON: Centralized Conferencing Working Group. Mechanisms for privacy and security are important requirements for the resulting protocols.
The deliverables of XCON, listed as part of their charter include creating:
A basic floor control protocol. This was published in [2006] as RFC 4582: Binary Floor Control Protocol (BFCP)
A mechanism for membership and authorization control
A mechanism to manipulate and describe media "mixing" or "topology" for multiple media types (audio, video, text)
A mechanism for notification of conference related events/changes (for example a floor change)
CONFiance is an implementation of the XCON framework and BFCP licensed under the GPL and Academic Free License
In a web conference, each participant sits at their own computer, and is connected to other participants via the internet through an application which a "host" company provides and charges for its use. This can be either a downloaded application on each of the attendees computers or a web-based application where the attendees will simply enter a "URL" or website meeting address to enter the live meeting or conference. These web-based applications are used either with Flash or Java technology.
A webinar is a type of web conference, although the direction of the presentation more often than not is primarily one way from the presenter to the audience as in a Webcast, which is transmission of information in one direction only, like watching a concert on the internet. A webinar however can be designed to be interactive between the presenter and audience. A webinar is 'live' in the sense that information is conveyed according to an agenda, with a starting and ending time. In most cases, the presenter may speak over a standard telephone line, pointing out information being presented on screen, and the audience can respond over their own telephones, preferably a speakerphone. The word 'webinar' is a portmanteau combining the words web and seminar.
Standards
Web conferencing technologies were not standardized for many years, a significant factor in the lack of interoperability, platform dependence, security issues, cost and market segmentation. In 2003, the IETF established a working group to establish a standard for Web conferencing, called XCON: Centralized Conferencing Working Group. Mechanisms for privacy and security are important requirements for the resulting protocols.
The deliverables of XCON, listed as part of their charter include creating:
A basic floor control protocol. This was published in [2006] as RFC 4582: Binary Floor Control Protocol (BFCP)
A mechanism for membership and authorization control
A mechanism to manipulate and describe media "mixing" or "topology" for multiple media types (audio, video, text)
A mechanism for notification of conference related events/changes (for example a floor change)
CONFiance is an implementation of the XCON framework and BFCP licensed under the GPL and Academic Free License
What is web video conferencing ?
web video conferencing is a piece of electrical equipment that performs video teleconference functions, such as coding and decoding of audio and video signals and multiplexing of video, audio, data, and control signals, and that usually does not include I/O devices, cryptographic devices, network interface equipment, network connections, or the communications network to which the unit is connected.
Technology of videoconferencing
A modern dual plasma video conferencing system. The Plasma on the left is primarily used to show people during the conference or the user interface when setting up the call. The plasma on the right is used to show data in this case but can be used for displaying a 2nd 'far site' in a multipoint call.
The core technology used in a videoteleconference (VTC) system is digital compression of audio and video streams in real time. The hardware or software that performs compression is called a codec (coder/decoder). Compression rates of up to 1:500 can be achieved. The resulting digital stream of 1's and 0's is subdivided into labelled packets, which are then transmitted through a digital network of some kind (usually ISDN or IP). The use of audio modems in the transmission line allow for the use of POTS, or the Plain Old Telephone System, in some low-speed applications, such as videotelephony, because they convert the digital pulses to/from analog waves in the audio spectrum range.
The other components required for a VTC system include:
Video input : video camera or webcam
Video output: computer monitor , television or projector
Audio input: microphones
Audio output: usually loudspeakers associated with the display device or telephone
Data transfer: analog or digital telephone network, LAN or Internet
There are basically two kinds of VTC systems:
Dedicated systems have all required components packaged into a single piece of equipment, usually a console with a high quality remote controlled video camera. These cameras can be controlled at a distance to pan left and right, tilt up and down, and zoom. They became known as PTZ cameras. The console contains all electrical interfaces, the control computer, and the software or hardware-based codec. Omnidirectional microphones are connected to the console, as well as a TV monitor with loudspeakers and/or a video projector. There are several types of dedicated VTC devices:
Large group VTC are non-portable, large, more expensive devices used for large rooms and auditoriums.
Small group VTC are non-portable or portable, smaller, less expensive devices used for small meeting rooms.
Individual VTC are usually portable devices, meant for single users, have fixed cameras, microphones and loudspeakers integrated into the console.
Desktop systems are add-ons (hardware boards, usually) to normal PC's, transforming them into VTC devices. A range of different cameras and microphones can be used with the board, which contains the necessary codec and transmission interfaces. Most of the desktops systems work with the H.323 standard. Video conferences carried out via dispersed PCs are also known as e-meetings.
[edit] Echo cancellation
A fundamental feature of professional VTC systems is acoustic echo cancellation (AEC). AEC is an algorithm which is able to detect when sounds or utterences reenter the audio input of the VTC codec, which came from the audio output of the same system, after some time delay. If unchecked, this can lead to several problems including 1) the remote party hearing their own voice coming back at them (usually significantly delayed) 2) strong reverberation, rendering the voice channel useless as it becomes hard to understand and 3) howling created by feedback. Echo cancellation is a processor-intensive task that usually works over a narrow range of sound delays.
[edit] Multipoint videoconferencing
Simultaneous videoconferencing among three or more remote points is possible by means of a Multipoint Control Unit (MCU). This is a bridge that interconnects calls from several sources (in a similar way to the audio conference call). All parties call the MCU unit, or the MCU unit can also call the parties which are going to participate, in sequence. There are MCU bridges for IP and ISDN-based videoconferencing. There are MCUs which are pure software, and others which are a combination of hardware and software. An MCU is characterised according to the number of simultaneous calls it can handle, its ability to conduct transposing of data rates and protocols, and features such as Continuous Presence, in which multiple parties can be seen onscreen at once.
MCUs can be stand-alone hardware devices, or they can be embedded into dedicated VTC units.
Some systems are capable of multipoint conferencing with no MCU, stand-alone, embedded or otherwise. These use a standards-based H.323 technique known as "decentralized multipoint", where each station in a multipoint call exchanges video and audio directly with the other stations with no central "manager" or other bottleneck. The advantages of this technique are that the video and audio will generally be of higher quality because they don't have to be relayed through a central point. Also, users can make ad-hoc multipoint calls without any concern for the availability or control of an MCU. This added convenience and quality comes at the expense of some increased network bandwidth, because every station must transmit to every other station directly.
The core technology used in a videoteleconference (VTC) system is digital compression of audio and video streams in real time. The hardware or software that performs compression is called a codec (coder/decoder). Compression rates of up to 1:500 can be achieved. The resulting digital stream of 1's and 0's is subdivided into labelled packets, which are then transmitted through a digital network of some kind (usually ISDN or IP). The use of audio modems in the transmission line allow for the use of POTS, or the Plain Old Telephone System, in some low-speed applications, such as videotelephony, because they convert the digital pulses to/from analog waves in the audio spectrum range.
The other components required for a VTC system include:
Video input : video camera or webcam
Video output: computer monitor , television or projector
Audio input: microphones
Audio output: usually loudspeakers associated with the display device or telephone
Data transfer: analog or digital telephone network, LAN or Internet
There are basically two kinds of VTC systems:
Dedicated systems have all required components packaged into a single piece of equipment, usually a console with a high quality remote controlled video camera. These cameras can be controlled at a distance to pan left and right, tilt up and down, and zoom. They became known as PTZ cameras. The console contains all electrical interfaces, the control computer, and the software or hardware-based codec. Omnidirectional microphones are connected to the console, as well as a TV monitor with loudspeakers and/or a video projector. There are several types of dedicated VTC devices:
Large group VTC are non-portable, large, more expensive devices used for large rooms and auditoriums.
Small group VTC are non-portable or portable, smaller, less expensive devices used for small meeting rooms.
Individual VTC are usually portable devices, meant for single users, have fixed cameras, microphones and loudspeakers integrated into the console.
Desktop systems are add-ons (hardware boards, usually) to normal PC's, transforming them into VTC devices. A range of different cameras and microphones can be used with the board, which contains the necessary codec and transmission interfaces. Most of the desktops systems work with the H.323 standard. Video conferences carried out via dispersed PCs are also known as e-meetings.
[edit] Echo cancellation
A fundamental feature of professional VTC systems is acoustic echo cancellation (AEC). AEC is an algorithm which is able to detect when sounds or utterences reenter the audio input of the VTC codec, which came from the audio output of the same system, after some time delay. If unchecked, this can lead to several problems including 1) the remote party hearing their own voice coming back at them (usually significantly delayed) 2) strong reverberation, rendering the voice channel useless as it becomes hard to understand and 3) howling created by feedback. Echo cancellation is a processor-intensive task that usually works over a narrow range of sound delays.
[edit] Multipoint videoconferencing
Simultaneous videoconferencing among three or more remote points is possible by means of a Multipoint Control Unit (MCU). This is a bridge that interconnects calls from several sources (in a similar way to the audio conference call). All parties call the MCU unit, or the MCU unit can also call the parties which are going to participate, in sequence. There are MCU bridges for IP and ISDN-based videoconferencing. There are MCUs which are pure software, and others which are a combination of hardware and software. An MCU is characterised according to the number of simultaneous calls it can handle, its ability to conduct transposing of data rates and protocols, and features such as Continuous Presence, in which multiple parties can be seen onscreen at once.
MCUs can be stand-alone hardware devices, or they can be embedded into dedicated VTC units.
Some systems are capable of multipoint conferencing with no MCU, stand-alone, embedded or otherwise. These use a standards-based H.323 technique known as "decentralized multipoint", where each station in a multipoint call exchanges video and audio directly with the other stations with no central "manager" or other bottleneck. The advantages of this technique are that the video and audio will generally be of higher quality because they don't have to be relayed through a central point. Also, users can make ad-hoc multipoint calls without any concern for the availability or control of an MCU. This added convenience and quality comes at the expense of some increased network bandwidth, because every station must transmit to every other station directly.
Why web video confrencing ?
1. Meet face to face with participants from across the globe. It makes your video meetings as simple and effective as holding an in-house meeting. Meeting face-to-face is made real with web video conferencing. With the latest in video technology, high quality customer service, and extensive global coverage,and it also delivers successful videoconferencing meetings anytime, anywhere, using a range of customer-driven services.
2. More convinient to various users
3. Faster and more flexible collaboration
4. Just-in-time Due to the fact that time is the most valuable asset so no one prefers waste a time.
2. More convinient to various users
3. Faster and more flexible collaboration
4. Just-in-time Due to the fact that time is the most valuable asset so no one prefers waste a time.