Yesterday I had a discussion with a co-worker about distant learning. This sparked the thought to write down some of my thoughts on this subject. To start I wanted to discuss Video Conferencing on the Web. Video conferencing on the Web is something that many people want but it does not make much sense. Let me explain.
When you are communicating on the Web you have to think that you need to budget your bandwidth or how many bits of information you can send and receive from the web in a second. This is normally measured in Kilo bits per second or Mega bits per second. Today’s broadband connections usually receive information (download) faster than they send (upload) information. These connections are optimized for web browsing. It is not uncommon to limit your send (upload) bandwidth to 300 to 500 kilo bits a second. For this discussion lets say we have a 500k connection.
Another thing to keep in mind is the connections between computers on the Internet are one to one. This means is that sending something to two different people it takes twice the bandwidth as sending this information to one person. Normally we work around this using servers. Servers are computers with high bandwidth Internet connections, they can send information to multiple computers quickly and efficiently. You can send your information to a server, this server can turn around and send it to many other computers.
Let’s do some math. Say you want to make a Skype video call to Grandma. It will take about 30k of your bandwidth to send the audio, and 200k to send the video total of 230 k. So I can quite easily use my 500k upload bandwidth to have this video call with Grandma. I can see Grandma and she can see me, if the grandchildren are young it is very valuable to have the video content. Normally this video is just a talking head, which does not communicate much information but when this is a personal relationship this valuable. You can see the person, some facial expression, you gain personal information. I used Skype in this example but there are may ways to make a video call on the Internet, Mac users have the IChat to easily give you this connection.
When you are using this to communicate to multiple people this becomes much more complex. Now your 230k bandwidth needs to be multiplied by the number of connections. So if you have 10 people online this 230k connection becomes 2300 kb per second, more than most broadband connections can handle. Even using a server you are tying a great deal of bandwidth up to show a talking head. Is it worth spending the bandwidth for a talking head? If we just used the audio now we are talking 300k, this can be handled much easier, especially if you use a server.
If you have graphical information that goes along with the audio, such as slide show, or a sketch of what your talking about. This information has a high value, and it takes less bandwidth than live video. When you think about this it is a static image with a little movement, versus a great deal of detail that can change constantly. Most of the popular e-learning/conferencing programs focus on sharing your desktop so that you can share what you are seeing on your computer screen with your audience. You can play a recorded video to illustrate your point, now you are spending your bandwidth with wisdom, spend it for the valuable content when you want.
I am only talking about video conferencing, recorded video on the web is difference. Normally these are produced videos that contain more content than a talking head. Usually these are on demand so that you are not trying to send the video to several computers at one time trying to keep this in sync with the rest of the presentation.
I hope this illustrates my point that video conferencing on the web does not make much sense. Individual video connections have a high value, but to think of conferencing this you end up paying a large amount of your bandwidth budget for low value information.