Sep 1, 2005 12:00 PM, By Bennett Liles
Technological advances and world events have pushed videoconferencing to critical mass.
Videoconferencing had been a technology-in-waiting from the time AT&T introduced the first Picturephone at the 1964 World's Fair until about 10 years ago. Then, hardware started shrinking in size and price, while new compression techniques packed more data into the pipes and broadband access broke through to the suburbs. Now that the technology is here, a number of forces have converged to provide solid reasons for using it. Terrorism, shorter staff rosters, and the skyrocketing price of fuel have helped give rise to a new business mantra: It is much safer, quicker, and cheaper to move electrons than people.
Videoconferencing now routinely links business offices and connects troops with their families back home. High school courses unaffordable in rural districts are being effectively delivered from schools located many miles away. Though somewhat controversial, eICU (Enhanced Intensive Care Unit) programs allow patients in smaller hospitals to be monitored and, to a degree, examined by doctors from a larger facility.
In recent years, selecting a videoconferencing system has become more challenging than affording one for many potential buyers. Choosing the right system for the job involves consideration of several factors. The basic question is whether conferencing will occur between individuals, groups, or (as is the case in most educational environments) between an individual and a group. The systems made for these scenarios fall into three general categories, which we will examine in terms of physical layout.
These are installed for regular use in group-to-group situations such as business settings. Here, the room is designed around the system.Some businesses will recoup the substantial costs involved by renting out their room systems when they are not in use by their own company. Such installations typically require a full-time technical staff for setup and operation. Most often, the communication is made over a leased network offering superior bandwidth, and the system adds document and application sharing, whiteboarding, audio/video playback, and remote-controlled cameras to the 30fps video and audio communication features. The conveyance may involve packet-switched networks or broadcast-quality signals over land and satellite connections.
These systems are self-contained and usually move between rooms with broadband data connections. The camera, microphone, codec (for translating audio/video to data), and monitor are physically located on a cart, and participants control the system using a wireless touchpad. Some training and rehearsal is usually necessary for things to go smoothly. At least 20fps video is provided at full-screen resolution. Some room systems actually have the same rollabout components installed permanently into the room architecture with a more advanced codec for higher bandwidth and video quality.
These small systems are where the biggest advances have been made. Normally used for conferencing between individuals, desktop systems also can connect with room and rollabout systems for individual-to-group situations. Modern advances have enabled these low-cost stations to inhabit laptop computers and connect multiple sources. Suitcase models have found a strong market among field videojournalists. These don't skimp on the extra features. Many desktop systems add whiteboarding and data, document, and application sharing.
Unfortunately, there is no way to grasp the workings of videoconferencing systems enough to make an intelligent choice among them without knowing something of the communication standards that allow them to interoperate. The nice thing about communication standards is that there are so many from which to choose. Let's have a look at a few of the core recommendations from the the International Telecommunications Union (ITU), the body that suggests standard tech languages for videoconferencing, among other things. Each of these recommendations contains many sub-protocols that specifically address coding of audio, video, multiplexing, signaling, and control.
H.320: This recommendation addresses narrowband conferencing over circuit-switched (telephone-like) networks such as ISDN, which offers 128kbps, and an older service called Switched 56. Some dedicated networks offer fractional service that splits up a 1.544Mbps line into groups of 24 64kbps channels. For small businesses, dedicated fractional T1 is fairly expensive and requires frequent use to pay for itself. Internet access accounts for most of the T1 lines now leased by businesses.
H.321: This protocol group deals with narrowband videoconferencing via ATM or Broadband ISDN (B-ISDN) networks. These networks offer a higher bandwidth and better signal than H.320 conveyance. The B-ISDN service offers combined or “bonded” 64kbps channels, which can be dynamically allocated as needed.
H.323: You will hear a lot about this one. This involves narrowband videoconferencing over packet-switched IP networks without guaranteed quality of service, such as LANs, WANs, and the Internet. This popular recommendation also addresses several specific IP network elements including gatekeepers, gateways, and multipoint services. The gatekeeper acts as an IP traffic cop to prevent congestion and as a phone directory to translate alias names to IP addresses. It registers terminals, provides call control, and manages bandwidth usage. The gateway manages connectivity on H.323 networks by providing transcoding services, signaling, and system control. Multipoint services allow conferencing between three or more terminals in one session through a Multipoint Control Unit or MCU. This may have the form of a separate unit, or the MCU may be incorporated into each participating terminal. Multipoint may be centralized (like a telephone bridge), decentralized, or configured as a hybrid between the two. Centralized multipoint is in greater use currently, but it uses more bandwidth than a decentralized configuration.
H.324: This is everybody's network for the lowest-cost videoconferencing, normally between two individuals using desktop systems. This recommendation concerns very narrowband videoconferencing over plain old telephone service (POTS) dial-up, switched networks. It's your basic video phone call.
T.120: This ITU recommendation involves application- and data-sharing along with whiteboarding. These features are very popular on all videoconferencing systems, but they have particular appeal on low-bandwidth desktop systems, where video tends to hog the minimal pipe in use. Keeping T.120 applications separate from video transmission enables users to greet by video and then switch to audio with application-sharing and whiteboarding to avoid frequent freeze-ups and drop-outs.
SIP: Session Initiation Protocol is the new kid on the block, but it has vast potential, particularly in desktop videoconferencing systems. SIP is an IP signaling protocol similar to H.323, but it enables easy integration of voice, web, and video. SIP is unique in that it incorporates instant messaging, which allows perfect ad hoc videoconferencing setup. It is also very web-friendly, with a textual form that resembles HTML rather than the binary code of the older protocols. It would be wise to select a videoconferencing system that includes this next-generation protocol in its interoperability stable.
Now that we have brushed up on a few of the most popular transmission standards in use, let's have a look at some of what is offered in the exploding market of videoconferencing systems.
Aethra USA offers a wide range of videoconferencing hardware, including video phones, desktop systems, and rollabout systems. Among their most impressive high-end products is the Supernova Star 250 rollabout system. Featuring dual 50in., 16:9 plasma monitors and voice-tracking technology, the Supernova 250 is user-friendly and ideal for corporate environments. Voice tracking enables the camera to follow anyone who is speaking while moving around the room. Dual-stream video allows two video sources to be transmitted so that video and graphical information can be presented simultaneously. The system features multiple connectivity with 768kbps on ISDN-BRI (Basic Rate Interface), up to 3Mbps on IP networks, and up to 2Mbps via ISDN-PRI (high-bandwidth ISDN). An onscreen, multilingual user interface makes setup easy with a remote. User ease is extended with automatic audio, video, and rate adjustment, plus automatic monitor-on with an incoming call. The mixed-mode Multipoint Control Unit and remote diagnostics and management features round out this feature-packed system. For tighter spaces, the product is available as the Supernova Star 243 with two 43in. monitors.
Broadcast International presents the Interact videoconferencing system with open platform compatibility with various monitor options. The Interact system uses a multi-codec technology called CodecSys that offers the unique ability to dynamically manage a library of standard and specialized codecs. This enables the system to instantly adapt its transmission technique from one frame or scene to the next, permitting full-frame, full-motion video and even high-definition video at a 50 percent to 75 percent reduction in bandwidth. The Interact videoconferencing system offers multiple bandwidth operation from 64kbps to 1.5Mbps with full-screen video at 128kbps and up, auto answer, up to three camera inputs, full-duplex audio with echo cancellation, and compatibility with Interact H.323 MCUs. The system includes a base unit, a Sony PTZ color video camera with wireless remote, an Acoustic Magic microphone, a keyboard/mouse, four alkaline batteries, and the user manual.
Among several videoconferencing products, D-Link markets the DVC-1000 i2Eye VideoPhone. An innovative device used at the consumer desktop level, the DVC-1000 does not require a computer for conferencing. Setup involves simply connecting a telephone and TV set to the device and running an Ethernet cable to a cable modem or DSL connection. Capable of video display up to 30fps with 95kbps to 512kbps data transmission rates, the unit offers setup wizards for easy configuration and personalized displays. Calls can be made or answered with the remote control, and caller ID allows the user to verify who is calling before going online. For compatibility, the unit complies with the ITU H.323 recommendation for broadband, packet-switched networks. It also features selectable display modes for small, outgoing video display of picture-in-picture or full-screen incoming video display. Setup is simple, and at $200, the product is worth a try for one-on-one desktop videoconferencing.
LifeSize Communications has entered the videoconferencing market with its high-definition videoconferencing product line. Among the company's offerings is the LifeSize Exec for conferencing with up to four people at the monitor. The unit showcases a 17in., 16:9 aspect ratio monitor, a high-definition conference phone, a conference camera with fixed 70-degree wide-angle lens, auto-white balance and back-light compensation, WiFi interface, a headset jack, and a wireless remote control. Multipoint bridging allows eight-way conferences, and dual streaming enables simultaneous transmission of camera and graphics. The unit is interoperable with networks from 64kbps to 5Mbps through H.264, H.263, and H.361, with H.323 and SIP support showing high-definition display (1280×720 pixels) at 1Mbps. Security features include AES encryption support, automatic key generation and exchange, and H.234 encryption key management. LifeSize Exec retails for less than $8,000.
Polycom is a long-time leader in videoconferencing systems, offering a model to suit almost any need, from the desktop to the boardroom. Among the company's higher-end products is the VSX 8800 for conference room group scenarios. The VSX 8800 may be integrated into an existing installation for a custom look or used with the Polycom Executive Collection, which features two 50in. plasma monitors. The product is compliant with H.323 and H.320 for 2Mbps connection over IP or circuit-switched networks with ISDN. Security is through Advance Encryption Standard support. Sound at 14kHz is provided with StereoSurround speakers projecting from each side. With 460 (PAL) or 470 (NTSC) lines of TV resolution and a 10X zoom range, the PowerCam Plus camera automatically tracks the speaking presenter. Auto-focus, auto-white balance, and iris are included. People+Content offers two simultaneous video transmissions — one for camera video and the other for graphics display — from any endpoint. Two tabletop microphones with flotation feet provide 360-degree sound pickup with minimum tabletop noise transmission. The internal MCU enables a total of four endpoints in the conference, with automatic voice-activated video camera switching. Features also include password protection for incoming calls and IP telephone support. The VSX 8800 lists for $12,000 to $13,000.
Among its many products for videoconferencing, Scotty Group offers the Scotty Warp 2 desktop solution. Reversing the philosophy that a computer is not needed for conferencing, the Warp 2 makes the statement that the same desktop computer that serves so many other needs can also be your window on the world of videoconferencing. Designed to operate over ISDN (H.320) or IP (H.323) networks, the station integrates a 15in. TFT monitor, a microphone, a camera, and two 2.5W speakers, with inputs for other devices. The camera has a fixed 6mm F2.0 lens, and there is an additional 75Ω composite video input and headset connection. The unit features wideband acoustic echo cancellation, two USB ports, an ISDN-BRI adapter, and Ethernet 10/100 Base-T connections. External document cameras can be controlled by the Scotty Teleporter software, and far-end camera control is H.281-compliant. The whole unit weighs 18lbs. and retails for less than $4,000.
Sony has introduced the PCS-G50 system as a part of its newly expanded Ipela line of videoconferencing products. The name is a combination of the IP protocol and the Italian word bella for beautiful. A high-end conference room system, the PCS-G50 offers scalability to suit a wide range of installation scenarios. The system uses H.263 4CIF format for a maximum video bit rate of 4Mbps, but it can also support H.264 and other previous codecs for compatibility with older videoconferencing equipment. The unit features an internal MCU for multipoint conferencing between up to six endpoints, or ten endpoints with two PCS-G50 units cascaded, and this system can mix calls between ISDN and IP networks. The product can also record AV to Memory Stick media. Included are data sharing capability with digital whiteboard support, site name display, MPEG-4 sound, secure communication through advanced encryption standard (AES), and a versatile Remote Commander for wireless control with a call log and storage and internal address book. List price for the PCS-G50 is $5,800.
For the executive desktop, Tandberg offers the 1000 MXP among its many videoconferencing products. With H.323, SIP, and H.320 connectivity, the 1000 MXP sports a great deal of versatility in a small package. The camera has a 64-degree horizontal and 49-degree vertical field of view. This, along with a 12.1in. LCD screen, speakers, and microphone, is integrated in one small frame with a wall-mount option. Dual Stream technology allows simultaneous video send and receive in any environment with PAL and NTSC standard support and 30-frame video at 169kbps and above. For added privacy, the unit accepts a headset via 2.5mm mini jack. Secure remote management is provided through password-protected HTTPS access. With all this, the product weighs only 9lbs.
Vcon, of Israel, supplies videoconferencing systems for anything from the largest high-definition room installations to the smallest desktop setup. Its most mobile product is the tiny ViGO H.323 personal conferencing appliance for laptops and desktops with up to 1.5Mbps over IP. Available in Standard and Executive models, the ViGO offers a highly mobile videoconferencing solution with three modes of operation. Using vPoint software in a “software client” mode, the system can use any USB-connected camera for conferencing. With the ViGO base unit connected to a laptop or desktop PC and sharing the processing load, the system delivers business-quality video and sound. Without the ViGO or a camera connected to the computer, the vPoint software runs in Viewer+ mode for two-way sound and receive-only video. The unit features full-duplex echo cancellation, data sharing, file transfer, whiteboard functions, a USB hub, far-end camera control, an alternate video input, and a personal video email application called vClip.
The Vista EZ media station from VTEL Products Corporation can function in any videoconferencing environment from a desktop to a small conference room. Designed for H.323 IP connection via LAN, DLS, cable modem, or optional wireless LAN interface, the Vista EZ includes an integrated Windows XP or 2000 computer with CD-ROM drive, two USB ports, a PTZ camera with 10X optical and 40X digital zoom, an omnidirectional microphone, and a QuickTouch wireless remote control. The hardware includes two camera inputs with PTZ control and an S-Video VCR playback input, audio line-level output, two microphone inputs, one VCR playback input, and an omnidirectional microphone. There is also a web-based soft tablet for system remote control. All these features add up to a very mobile and versatile conferencing tool.
As is evident from the selection here, the world of videoconferencing has expanded to include a system for every possible scenario, from the smallest and most mobile PC stations to impressive room systems for the most elegant and dynamic corporate environment. Armed with a little knowledge on the features of hardware and the various forms of conveyance, one can choose a system and accessories that will suit the task.
For More Information
The terms listed here are among those most commonly encountered. Familiarity with these concepts will provide an advantage in determining which system meets specific needs.
CIF: A video format that forms part of the H.261 standard. It specifies 30fps in which the frames contain 288 lines with 352 pixels per line.
Codec: A coder/decoder. A hardware or software device that compresses and decompresses digital audio, video, and data signals.
Echo suppression: Prevents participants from hearing their own sound returning to them with a distracting delay. If not set properly, echo suppression can cut off the beginning of words or sentences.
Latency: The time required for packets to reach their destination on an IP network. With office applications, this is not critical, but it can become noticeable in IP network videoconferencing.
Transcoding: Converting one format to another, as in translation of H.320 signals to H.323.
MCU: Multipoint Control Unit. These devices enable videoconferences between several endpoints so that participants from many locations can see and hear all the others. These are now built-in features of many videoconferencing systems.
Voice-Activated Switching: A feature, usually of an MCU, that selects the participating video signal that has sound originating from that location. This usually takes a little practice to use effectively.
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