Videoconference
From MariachiWiki
Contents |
Definition and a bit of History
As the name says, video conference refers to communicating at distance using video and audio. While there are many different video conference technologies, today most of them use the internet (sometimes referred to as IP videoconferencing). The addition of multimedia to the video conference makes possible for different parties to present slides, movies and images (or even formulas) over distances making this tool ideal for collaborative work. However, videoconference only complements live meetings.
IP videoconferencing started a while back. Although most people think that it is something that belongs in the 21st century, the very first software that became available is actually quite old. Those that remember CU-Seeme are because they are too old! Anyway it came out in the early part of 1992. VIC and VAT used mostly with Silicon Graphics Indigo computers (yes I had one), came out around 1994. They became the very first tools we used to communicate over distances and they were quite useful. Commercial products quickly became available with lots of outfits selling their proprietary hardware and software. Today most scientific collaborations use one form or other of videoconferencing.
What is out there?
There are many different video conference systems available. Each offer different features. Each will put a different demand on the performance on the network bandwidth. So here's few examples:
- VRVS - VRVS is a technology that came out around 1994. The first version of its components RAT, VIC and WB were written for Silicon Graphics and conferencing were mostly point to point. Today VRVS is available to all platforms.
- EVO - EVO is an improved VRVS. It uses a lot of Java and few components from VRVS. It does have the look and feel of a VRVS but with a better management for contacts, etc... It works on Macs and PCs, although better on PCs. Evo Test Image
- ESNET - ESNET, the Energy Sciences Network, is supported by DOE and used mostly by academia. The strong points of ESNET are the high quality (near TV quality) video and audio. It requires a high bandwidth, sometimes 768 kbps to work properly. Both BNL and Stony Brook have video conferencing rooms equipped with hardware for ESNET conferencing. For Macs there are free clients - OphoneX and Xmeeting. You need to be a registered user of ESNET.
- iCHAT - iChat it is a proprietary Apple Computers video conferencing. It requires relatively high bandwidth, and limited to 4 participants. The image quality and audio are exceptionally good. Echo suppression is one of the best.
- Skype - Skype is mostly internet telephony. However it has support for video. It is relatively easy to use and multiplatform.
- Marratech - Marratech is a commercial video conference software. This is the one we use.
What general hardware do you need?
To join a video conferece as an individual you will need a webcam and a headset with microphone. The webcam is not very necessary if you only want audio. Why do you need a headset with microphone? The number one plague for video conference is ECHO. What is ECHO? as the name says it happens when whatever is coming out of your speakers make into the microphone. So for example, if you have a microphone and computer speakers whatever your friend says feed back into the microphone. YOU don't hear anything, but all your friends connected to the converence will. So pay attention to this detail.
What is the cure for ECHO? a headset with microphone is good for one person. If you have more, then you'll need an echo cancelling microphone.
Is ECHO an universal problem? NO. Software such as iChat do echo cancelling using proprietary software.
General Rules
Video conferences are just like talking in a group. If two or three people talk at the same time it is really hard to understand what is going on. So, make sure you follow a certain order, or just mute your microphone. It is often good to have a mediator and a schedule for speakers if your meeting involves that.
