How Video Conferencing Works – Multimedia, Interactive Communication Across the Miles

Author : Lucy P. Roberts
You may think you understand video conferencing pretty well until someone who
isn’t at all familiar with it approaches you for a simple definition. When they
ask, “What exactly is video conferencing?” you could suddenly realize you’re at
a loss for words.
The simplest definition of how video conferencing works is simply by the
integration of video, audio and peripherals to enable two or more people to
communicate simultaneously over some type of telecommunications lines. In other
words, you are transmitting synchronized images and verbal communications
between two or more locations in lieu of them being in the same room. How video
conferencing works is a little bit harder to explain than answering the
question, “What is video conferencing?”
Millions of people use video conferencing every day around the globe, but
very few people know just how the technical aspects of the process work. The
main ingredients of successful video conferencing are video cameras,
microphones, appropriate computer software and computer equipment and
peripherals that will integrate with the transmission lines to relay the
information.
The analog information recorded by the microphones and cameras is broken down
into discreet units, translating it to ones and zeros. A Codec encodes the
information to a digital signal that can then be transmitted to a codec at the
other end, which will retranslate these digital signals back into analog video
images and audio sounds.
The theory’s the same, the transmission has changed
In the earlier days of video conferencing, T1, ATM and ISDN lines were used
almost exclusively but were really only practical for room-based video
conferencing systems. These dedicated lines were expensive and only large
corporations tended to have the facilities and money to invest in this type of
set-up.
As the Internet became more a part of the everyday lives of all businesses,
however, it changed how video conferencing was conducted. The TCP/IP connections
of the Internet are much less expensive and can carry large quantities of
information, including video packets for conferencing, relatively easily.
Because of this, video conferencing has become much more prevalent in small
businesses and in desktop packages that can be set up with software for
computer-to-computer networking.
Compression makes video transmission practical
The problem that arises when you convert analog to digital for transmission
is the loss of clarity in an image. Analog signals are a continuous wave of
amplitudes and frequencies showing shades and ranges of color as well as depth
and brightness. When you convert to digital, which is strictly 0’s and 1’s, you
then need to develop a grid to represent values, intensities and saturations of
different color values so that the image can be interpreted and reformed at the
receiving end.
This vast amount of digital information requires huge bandwidth and means
that the time it would take to transmit video images would be impractical for
most applications. That’s where compression is crucial. When determining how
video conferencing works, one of the most important elements is the compression
ratio.
The higher the compression ratio, the more quickly the information is capable
of being transmitted. In many cases, however, this also means some loss in
clarity or audio/video quality. For instance, a compression ratio of 4:1 would
be terribly slow but have a fantastic picture quality. But by the time it was
transmitted, everyone at the other end would probably have left the room for a
cup of coffee. Lossy compression discards unneeded or irrelevant sections of a
signal in order to transmit only the essentials, speeding up the transmission
time significantly but sometimes resulting in loss of quality.
Compression can either be intra-frame or inter-frame for material that is
repetitive or redundant, such as that wall behind the conference participant.
Since the wall remains static and never changes, this image is redundant and can
be eliminated from transmissions to an extent with proper compression.
Intra-frame compression assumes the redundancy will be present in parts of a
frame that are close to each other. Inter-frame compression assumes that there
is redundancy over time (i.e., like that wall). Either of these can achieve a
fairly high degree of accuracy and reduce the bandwidth needed for transmittal
of signals.
A newer version of compression/decompression is SightSpeed technology,
developed by Cornell University. SightSpeed compresses only images considered
essential and eliminating what is considered ‘filler,’ relying on the brain to
fill in the decompression at the other end. Based on an artificial intelligence
model, SightSpeed achieves compression of about 90:1, compared to the typical
15:1 for video conferencing.
Any video conferencing session you use will provide compression of the
transmission signal. The key is determining the balance between speed and video
picture quality that is right for your needs.
Point to point video conferencing
Point to point video conferencing is just what it sounds like â€" a link
between two different points on the planet, or two different video conferencing
terminals. It could be between an office in New York City and a conference room
in Munich. Point to point video conferencing can easily be initiated by someone
on one end contacting the other end as though making a standard telephone call.
There are no special arrangements to be made other than knowing that the
participants will be there.
Multipoint conferencing is more complex
Multipoint conferencing is more complicated because it has to coordinate
several different locations simultaneously. Since you can’t be in direct contact
with several places at once while they are all in contact with others, you need
one source that will tie them all together. In video conferencing, this is
called a multipoint bridge or multipoint conferencing unit (MCU).
An MCU enables multi-location video conferencing by providing a sort of
“central processing center” for all of the locations through which all the
information flows. The MCU receives all information from the various locations
and then sends it out to each location. In some cases the MCU is located on a
particular PC, and in other cases it is located on a remote server (the most
common structure, particularly for more powerful MCU networks).
Audio is usually sent and received simultaneously in all locations with an
MCU with no problem because of the relatively small bandwidth needed for
transmittal. It is broadcast in what is called “full duplex” mode, meaning
everyone can talk and hear at the same time with no cutting off when one person
or another speaks.
Video transmission, however, can be broadcast in a number of ways with an MCU
depending upon the quality of the software and the complexity of the system.
Some common types of video transmission for video conferencing include:

Continuous Presence video conferencing, which allows up to four
conference sites to be seen simultaneously on split screens. This is usually
used if you have a small group or individuals in separate locations and will
primarily be seeing close-up shots.
Universal Control video conferencing is controlled by the
initiating conference site. The primary site determines who sees what at all
other sites.
Voice Activated video conferencing is by far the most common type
used today. The image with these systems shifts to the site that is currently
activating the microphone so that you can always see whoever is speaking.
However, if there is a good deal of background noise participants should mute
their microphones when they aren’t talking in order to avoid the image jumping
about needlessly.

Overcoming the language barrier
Obviously, communicating through video conferencing can’t be achieved unless
both ends of the conference are “speaking the same language.” That is, whatever
is being transmitted electronically will need to be reassembled properly and
heard and seen clearly at the other end. The Codec system (Coder-Decoder) is
useless if both ends aren’t using the same virtual language to interpret the
signals.
The International Telecommunications Union (ITU) developed a set of standards
in 1996 dubbed H.323 to outline specific guidelines for Video Conferencing
standards and protocols so that compliance and support across networks would be
easier to achieve and maintain. Since then, many manufacturers and developers of
video conferencing tools have adopted the H.323 guidelines as their own.
Web conferencing solutions such as Click to Meet, Lotus’s SameTime, and WebEx
also offer corporate solutions that are based on Internet video conferencing.
These systems have shared protocols that can be downloaded and used anywhere at
any location for subscribers through the Internet. These are becoming more
popular with companies who like the convenience and user-friendliness. They will
no doubt become more and more refined over time, vying with and perhaps
surpassing the H.323 standards.
Overcoming firewall issues
There are, of course, obstacles to overcome when you take a look at how video
conferencing works. After all, you’re sending vast amounts of translated data
either directly or through a gatekeeper system (the MCU) that is switching and
transferring information between a variety of computers. Just about any business
these days has a firewall system to provide security and protect the system from
potential viruses. Trouble is, many firewalls also block the transmission of
data for video conferencing.
Recent innovations have largely circumvented these problems by designing
firewall solutions that recognize video conferencing signaling requests and allow
the information packets to bypass the firewall or router without disabling the
firewall protection for other traffic. Even with this, however, there may be
occasions when packets are dropped because of heavy traffic on the system, so
investing in a firewall system that can handle substantial traffic is essential
to quality video conferencing performance.
How video conferencing works will certainly evolve over time and improve in
the coming years, but a basic understanding of what it is and how it works now
will help you make the best choice for you when you’re ready to begin using
video conferencing yourself.
This article on the "How Video Conferencing Works" reprinted with
permission.
Copyright © 2004 Evaluseek Publishing.
About the Author
Lori Wilkerson is a full-time freelance writer who loves her job because it
gives her the opportunity to learn more about the world every day. Right now,
she knows a little bit about almost everything, and a lot about
video conferencing,

video teleconferencing, and

desktop video conferencing. She has two dogs who are spoiled
and one teenager who is not. She does her video conferencing in pink bunny
slippers.
Category : Gourmet

Home Water Filters: Undersink Water Filters

Author : Mike Tracy
There are several different types of water filters that can be installed underneath the sink. These undersink water filters provide bottled-water taste at a fraction of the cost. Installation of undersink water filters is fairly simple and straightforward, requiring only the undersink water filter kit with compression fittings and mounting hardware, and teflon tape.To begin the installation, it is necessary to disconnect and remove the line that connects the cold-water supply to the faucet, which is located underneath the sink. This normally involves no more than loosening the securing nuts, along with removing the rigid supply line. Once the line is disconnected, it is important to place teflon tape on the fittings in order to ensure a good seal for the new filter lines that will be installed. The filter is then installed between the cold-water supply and the faucet. This is done in the space where the rigid line was removed. The water filter canister can then be installed in a way that will allow the water to enter the filter through an inlet. The water can then pass through the filter medium, and flow out of the filter through an outlet. This will result in filtered water being delivered to the faucet. The canister body can actually be removed from the lid so that the filter which is inside can be easily accessed and changed when it becomes necessary. The water will later be forced through the filtering media that's housed inside the canister.It is important to double check that the filter is being connected to the cold water supply line. The filter will not operate in the proper way if it is accidentally connected to the hot-water line. Make the top connection by attaching one end of the second flex-line to the kitchen faucet. Once the flex-line is attached to the faucet, the other end of the line can be attached to the outside of the filter. Once this is done, it is important to make sure the canister is mounted in a position high enough to allow enough clearance beneath the canister. Once this step is complete, the undersink water filter is installed, and can be easily accessed in the future to change the filter.For more information about house water filters please visit http://WaterFilters.Blueble.com and buy water filters online.
Category : Home-and-Family:Home-Appliances

Increasing Link Popularity for Directory Owners

Author : Janesmith

Do you own either a general or niche directory? If so, you know that these can be quite lucrative if they are promoted and marketed correctly. But with that being said, you need to know where to start this marketing strategy if you want to be a success. For some directory owners this is a problem that they may never overcome. Luckily, there are several things that you can do in order to increase your link popularity. The best thing that you can do as a directory owner is to submit your site to a general and/or niche directory directory. While that may sound like a mouth full, these sites are actually pretty easy to understand. A directory of directories is a place where you can submit the site that you own. This will in turn give you backlinks to your site, which as you know will go a long way in increasing search engine rankings. Remember, the more directories that you submit your site to the better off you will be in the long run.Another reason for submitting to these directories is that they are a great place to advertise what you have to offer. These directories attract two different types of people. First off, visitors who are looking for quality directories will visit these catch all sites and subsequently be taken to yours. And better yet, other directory owners will come across your site and may purchase permanent links, feature links, or offer an exchange.As you can see, being a directory owner is something that will keep you occupied for hours on end. This is not the type of site that you want to build, and then let sit. If you own a directory you can make a lot of money if you are willing to put in the time and effort.In order to take your directory to the top of the industry you need to consider submitting it to as many larger directories as you can. This will increase your link popularity, traffic, and hopefully your profits. Written by Jane Smith. Submit your web directory to the Directories Directory or submit your website to a General Directory

Category : General Link Popularity

The Magnificent Ski Areas in Colorado

Author : Groshan Fabiola

Winter sports lovers, particularly skiing enthusiasts are guaranteed to find the ski areas in the State of Colorado the perfect place for practicing their hobby. Renowned for the variety of its properly equipped, competitive ski resorts and its magnificent snowy slopes, the State of Colorado draws thousands of tourists in search of fun, excitement and adrenaline each year. Persons who choose ski areas in Colorado are often overwhelmed by the imposing, colossal figures of the snowy mountains and the breathtaking, wild landscapes found in the State. Ski resorts in Colorado greatly vary in terms of geographical location, accessibility and amenities, but they all share the same characteristic: vast, beautiful slopes, equally suitable for novice and experienced skiers, as well as other winter sports fans. For the regular tourist and the passionate with skiing, Colorado ski resorts often seem like heaven on Earth. Ski areas in Colorado include popular names, such as Aspen, Snowmass, Copper Mountain, Breckenridge, Vail, Beaver Creek, Keystone, Wolf Creek, Eldora and Steamboat, to name only a few. Together, these Colorado ski areas offer people unlimited access to a variety of welcoming slopes, impressive through their high altitudes, very long distances covered and impeccable quality. Two of the most popular and appreciated ski resorts in Colorado are, undoubtedly, Aspen and Snowmass. Aspen is located in Pitkin County, very close to the city of Aspen. The ski resort is flanked by the imposing Aspen Mountain to the North and Bell Mountain to the South. Although Aspen is a relatively small ski area compared to other ski areas, (Snowmass, for instance) it compensates for that through its impressive elevation, (2422m at the base and 3417m at the top) its stunning landscapes and of its smooth, high-quality ski slopes. Comprising around 3000 acres, Snowmass is another popular ski area in Colorado. Snowmass is renowned for its friendly, welcoming atmosphere and extensive ski-in / ski-out lodging and combines accessible, novice slopes with challenging, extreme skiing terrain. These characteristics render Snowmass suitable for both experienced and aspiring skiers. Copper Mountain Ski Resort, the largest ski resort in Summit County is also a resonant name among the community of skiers. Copper Mountain Ski Resort corroborates impressive elevation (2960m at the base and 3753 at the top) with very diverse ski terrains, ranging from beginner to expert level. Beaver Creek (common host of Alpine Skiing World Cup events), Vail (the sister resort of Beaver Creek), Breckenridge (popular for its progressive-difficulty slopes on the Rocky Mountains), Wolf Creek (renowned for the impressive amounts of snow found in the region) and Keystone (famous for its nocturnal activity both on and off the slopes) are also prominent, worth-mentioning ski areas in Colorado.Persons who have been to these wonderful places and have tested the impressive slopes found in these regions became regular customers for the local ski resorts. The polyvalent nature of the ski resorts in Colorado renders these places perfectly suitable for amateur and professional skiers, other winter sports enthusiasts and tourists in search of fun and excitement. If you havent yet discovered the beauty of the ski areas in Colorado, you should definitely include these places on your holiday destination list in order to have a remarkable, unforgettable experience! So, if you want to find out more information about Ski Resorts or even about Ski Areas In Colorado, you should click these links.

Category : General Sports: Winter/Snow

Video Conferencing Hardware and You

Author : Mark Walters
If you are new to the game there is some video conferencing hardware to consider.Gone are the days when you had to fly across the country and drain your company's expense account just to attend a two-hour meeting. Now, all you have to do is turn on your computer and you're ready to go.But if you are new to the world of video conferencing online, it may not be that easy. You might not have any idea of the different video conferencing hardware components that you will need to get started. To make things even more difficult, a quick Internet search for the phrase "video conferencing camera" brings up more than 42,000 entries. Yikes!In the interest of protecting your sanity and boosting your status in the eyes of your boss, we've provided a brief list of the basic pieces of equipment you'll need to get conferencing and good places to buy them:Personal ComputerMost offices these days are equipped with personal computers (PC). These temperamental creatures are a necessary evil to keep your business organized and competitive in the twenty-first century market. A PC is also completely essential to video conferencing, as your computer hooks up with other computers so that you can conduct your meetings online.ModemWhether DSL or dial-up, most offices these days are connected to the Internet. The web is a valuable tool in business today and almost everyone has a website - even your neighbor's dog. Internet connection is a must for online conferencing, as you actually have to be online for this type of conferencing. Dial-up services will work for video conferencing online, but your images will be less clear. ISDN connections work best as they provide the fastest connection speeds and clearest pictures.CameraA video conferencing camera is an important piece of hardware as it enables you to talk face to face to your colleague or customer across the country. Without them, you're just audio conferencing. Prices for video conferencing cameras range from a basic IBM model going for $40 to a snazzier PolyCom model that runs about $499. Logitech sells a model specially designed for laptops or notebooks.Cables and StuffYou will need a USB cable to convert the images that your camera records to a format that your computer can understand. USB Gear provides several different types of equipment that take up minimal space on your PC and will get the job done.MicrophoneUnless you want your video conference to become just a visual conference, some type of microphone is necessary for each participant to communicate with the others. Wideband Solutions sells different microphones designed to cover both small and large boardrooms. If you just need a microphone to cover you and your desk, Phoniex Audio sells a microphone that will do the job.HeadsetWhile not completely necessary, a headset is a convenient piece of equipment for any savvy video conferencer. Imagine trying to crunch some numbers on a spreadsheet and carry on a conversation about your budget with a phone awkwardly cradled in the crook of your shoulder, while your boss looks on from 300 miles away. Not exactly the put-together professional image you want to convey.Time to Shop!Ebay and Amazon are good spots to go for used equipment, but buyer beware - you never know what condition it might reach you in. Always be sure to use reputable sellers with good customer ratings. PolyCom is well known in the industry and sells top-of-the line equipment. You can also try NexTag. This site that provides a search of the best prices on whatever electronic equipment you specify.Mark Walters manages http://www.VideoConferencingStar.com and suggest you learn how to choose a Internet Webcam here.
Category : Computers-and-Technology:Video-Conferencing

What On Earth Is Going On In The Market?

Author : Sam P.O
You know it's absolutely crazy. Every time you think you understand the stock market, something comes up that makes you wonder whether there is any sanity in it at all.I mean, just take a look at the way the DOW has been behaving of late. One would be forgiven for assuming that the market has been taken hostage by a bunch of aliens, aiming to wreak havoc on our investments!It would seem that no sooner does the DOW Jones recover from a bad day's trading it swings back into a disastrous trading the following day. And these wild swings appear to have spread to other major indices as well.Exactly what is one to do under such circumstances and how do you protect your investments from being completely wiped out?Well there appear to be two schools of thought as far as this is concerned and depending on your risk appetite you can determine which way to go.The first school of thought is, move with the market, whichever way it goes. In other words, buy when the market is generally moving up and sell when the market is generally moving down In this case short selling of stocks would be the route advocated by this school of thought. This is good advice if you actually know how to do so and have the expertise to come out ahead. It is however a disastrous route to go, if you have no experience in this process, as it could quite easily result in complete loss of investment.The second school of thought suggests that if the market is this choppy and undecided, then this is the time to move into cash and stay there. In other words if you imagine the market as a bad storm, you need to take cover until the storm is over and calmer weather returns. Frankly, rather than try and be a hero, I think the second school of thought is far more appealing and sensible for the average investor. I would rather not make any huge returns, but have my capital investment safe, than put it to risk and which it gets wiped out on investment methods that I do not fully understand how to execute.Put another way, when the going gets tough, then the tough (wise) move to cash at the earliest opportunity. So ask yourself, are you going to try and remain wise, or do you want to risk being a directionless hero? The choice is yours, but I know what I'm going to be doing.Sam P.O.Sam is a financial and management expert with practical experience in advising and formulating workable solutions to clients.Watch out for more current articles on prevailing scenarios...Happy trading.He can also be reached via his e-mail:podera@gmail.com
Category : Finance:Stocks-Mutual-Funds

Benfotiamine And Diabetic Retinopathy

Author : Zach Malott
Damage from diabetes can occur in different areas of the eye. It can occur to the cornea, nerves controlling the muscles of the eye, the lens, optic nerve and retina. The retina is the complication that most people and medical professionals think of first in terms of diabetic complications.Diabetic retinopathy is simply damage to the light sensitive retina. This damage is brought about by hyperglycemia, the medical term for high blood sugar. Retinopathy is directly responsible for approximately 12,000 to 24,000 cases of legal blindness every year in the USA alone. It is reported that there are over 200,000 cases each year globally.Diabetic complications are even more insidious than these numbers because there are several other types of diabetic eye disease created wholly or in part by high blood sugar in diabetics.What Can Be Done To Prevent Eye Disease?It stands to reason that the more informed a person is about a particular situation the better equipped they will be to handle it. Diabetic eye disease is just such a case in point. We need to think of the whole person and not just the eyes when discussing diabetic education because diabetic complications run from eye disease, heart disease, nerve damage, kidney damage, etc. Although benfotiamine has been found useful for all of the above, for the sake of this article in terms of prevention, we will discuss diabetic eye disease in terms of diabetic retinopathy.Diabetic retinopathy is a disease that every diabetic faces the possibility of suffering from somewhere in the course of their disease. The better patients of diabetes are equipped to handle their disease, the lower their risk that they will develop retinopathy. If retinopathy does develop in a patient who is doing all he/she can do to lessen the impact of blood sugar on their bodies, the better chance that they can live productive lives despite the complications and the slower such complications will progress.What Works Best?Unfortunately, there are very few options that are showing much promise for the diabetic in terms of diabetic complications. Benfotiamine has been suggested recently to be a strong deterrent against the development of diabetic retinopathy and also shown to slow its progression significantly if it develops. It is showing great promise in the arena of retinopathy, neuropathy and heart/circulatory conditions brought about by excess sugar in the cells.Benfotiamine, a lipid soluble derivative of water soluble vitamin B1 (thiamine), has been used for the past 12 years in Europe for the treatment of neuropathy, retinopathy as well as heart and circulatory conditions and has shown no adverse effects.Much of the current research on benfotiamine can be discovered by typing the term benfotiamine into a search engine such as google, AOL, yahoo, etc.ConclusionDiabetic complications are a reality that must be an accepted possibility for every diabetic. Diabetic education is highly necessary so that the diabetic community is able to make informed decisions as to their treatment and prevention methodologies. There are few things that show great promise in preventing and/or helping neuropathy, retinopathy, heart and circulatory problems brought about by diabetes. Keeping blood sugar levels close to normal along with adequate exercise in line with the abilities of each individual has shown to help slow the onset of diabetic complications.Benfotiamine is a nutritional supplement that has shown to be helpful in Europe over the past 12 years in terms of diabetic complications and is now available in the United States, and might be worth the time to investigate further. How about for the diabetic who faces the insidious nature of diabetic complications?Zach Malott is CEO of Brentwood Health International, a nutritional supplement company involved in distribution and supplying wholesale, retail and end users.Mr. Malott is available to discuss the research as it applies to benfotiamine in the treatment and prevention of diabetic complications such as neuropathy and retinopathy. He can be reached at:Phone: 505.354.0526web site: http://www.emuhealthproducts.com/benfotiamine.html
Category : Attraction