Using Video, audio and multimedia for education and research

There are 2 different ways of sending video and audio across the Internet.

1. Download: This is where you have to wait for the whole of the video/audio file to arrive on your computer before you can play it. Normally you will save a copy of the file onto your computer which means you can watch again later offline, and can copy, edit and further distribute it. As long as you don't mind waiting for the file to download, you can watch clips that have a higher bitrate than your network connection allows.
2. Streaming: With media streaming you can start viewing the clip after only a small part of the video/audio file has arrived on your computer. This means that you can start to view the clip much more quickly than with download. However the clip cannot be saved to your computer. If you want to watch it again it has to be streamed to you again across the network. The bitrate of the clip will be limited by the speed of your network connection.

Streaming has some advantages for the distributor of the material:

• It makes it difficult for people to copy or redistribute material without authorisation.
• It uses the network capacity more efficiently
• The streaming server will be able to detect the user's network speed and deliver a version of the clip at the maximum available bitrate
• It means that the clip can be viewed by more people at the same time
• It enables live broadcast over the internet

However it means that your website has to have specialist streaming server software in addition to a normal web server.

There is a third way, which is called progressive download. This is a mixture of download and streaming; you can start to watch the file before it has all arrived, but once it has arrived you can save it to your computer.

Mobile phones

Digital media can be streamed directly to mobile phones. All that the content creator needs to do is create a version of the clip at the right resolution. However, the cost of doing this is very high because of high charges from the network providers so this is probably not yet a viable option.

Personal Digital Assistants (PDAs)

These can receive video and audio using their wi-fi connections. All that the content creator needs to do is create a version of the clip at the right resolution.

Podcasting

This is a way of transmitting material via a "feed", which means that the user subscribes to the service and material is then automatically sent to the address specified by the user. This means for example that video or audio clips can automatically be downloaded to your computer, PDA or mobile phone. This would be a good way to keep people up to date who are interested in your research project, or to disseminate teaching/training material in a timely way.

To find out more see:

http://digitalmedia.oreilly.com/2005/07/20/WhatIsPodcasting.html