What is desktop video? Desktop video means that you can sit at your desk and have a videoconference with someone who is sitting at his or her desk. (Think of a videoconference as a telephone conversation where you can see as well as hear the person on the other end of the phone.) Does this mean that we're finally at the age of the Jetsons with their video phones? Not quite. While the quality of desktop video is constantly improving, we are still a long way from the Jetsons. However, current video conferencing technology is adequate for many of today's applications.
To get started with desktop video, you need a sufficiently powerful computer with a fast connection, a video camera that attaches to the computer (usually via USB), and video conferencing software.
Most computers purchased within the last few years will be sufficiently powerful enough to run desktop video conferencing programs.
The computer:
Older desktop video systems required a special video input card be installed
into the computer. Most new video cameras attach to the computer using a USB
port. Make sure before you buy one of these cameras that your computer and
operating system support USB. (For example, Windows NT does not support USB.
Windows 98, 2000, and newer all support USB.) If you're a Mac user, there is a
product called IBot that connects to a firewire port. There is also an IBot
model for PC users that comes with a PCI firewire card.
The camera:
Cameras range in price from $35 for a basic model to several hundred dollars
for a more powerful model. The more expensive models provide a clearer picture
and more frames-per-second(fps). The less expensive models typically provide
15 fps while some of the more expensive give 30 fps; television is broadcast at 60 fps.
Some cameras include a built-in microphone; others do not. One frequent problem is
having the microphone positioned too close to the speakers resulting in either loud
screeching feedback or echoing. For best results you should use a headset with a
microphone, so having a camera with a built-in microphone isn't crucial.
The software:
For your computer to be able to connect with another for video conferencing, both
computers must be running software that can talk to each other. The easiest way
to make sure that the software packages will talk to each other is to be using
the same software. If this isn't possible, then as long as both software packages
adhere to the same videoconferencing standard they should still be able to
communicate with each other. H.323 is the international standard for IP Telephony;
you should make sure that any videoconferencing software that you use adheres to
this standard. Compliant software is available for Windows, Mac, and Linux.
The most widely used software for Windows is Microsoft's NetMeeting. NetMeeting comes with most versions of Windows, and it may be downloaded free from Microsoft's web site if you don't already have it on your computer. Some cameras (such as Polycom's ViaVideo) come with their own software. Both NetMeeting and ViaVideo are H.323 compliant, so users of one should have no problem communicating with users of the other.
Making a Connection:
Once you have the software on your computer, you need to initiate a call with
the other person. There are several different ways to get your computer to
connect to another for video conferencing. The most direct way is to "call"
the other computer using its IP address.
Every computer on the Internet has an IP address. When you launch most videoconferencing software it will tell you what your IP address is. You can then communicate this number to the person you wish to videoconference with, and they can call you. (Alternatively, they can tell you their IP address and then you can call them.) If you're in an office or a dorm room at the University, your IP address is usually static (it doesn't change). However, if you're using another Internet service provider you may have a dynamic IP address; this means that every time you connect to the Internet you may receive a different IP address. If someone gives you their IP address today it may not be the same when you try to call them tomorrow (or even an hour from now!)
Keeping track of IP addresses can be difficult, especially in a dynamic address environment. Another way to connect with someone is to use a Global Address Book (GAB) server or an Internet Locator Server (ILS). When you install your videoconferencing software it may ask if you want to register with an online directory server. If you register with one of these servers, then anyone else connecting to the same server can connect to you through that server. They don't have to know your IP address; they just need to know what name you used to connect with the server. Of course, they also need to be connecting with the same server that you're using.
Online Collaboration Tools
Most of the videoconferencing software also allows some sort of shared work
space. Most commonly this involves a shared "whiteboard" - think of a paint
program that both conference participants can see and modify - and/or shared
applications, where both participants can work on the same document (in Word,
for example, or share the same Excel spreadsheet). You don't even need to use
a camera to collaborate with these tools. You can connect to another computer
and use a microphone or typed messages to communicate and use the shared
whiteboard or application. To be able to share work space, both software
packages should use the T.120 standard.
The quality of videoconference also depends on the connection between the computers. Within the Penn State network and between Penn State and other institutions connected via Internet2 speed is adequate for good results. Using the Internet with all of its commercial traffic can be more problematic, and the speed of the connection varies greatly depending on the origination and ending location of the computers. To successfully use desktop videoconferencing you need some sort of broadband connection: Ethernet, Digital Subscriber Line (DSL) or a cable modem; a 56k modem is not recommended.
For more information and specific camera and software recommendations, see http://css.its.psu.edu/dvc/.