Audio and video on the Web.

Abstract

(Medical Education Web Page Series – Part 7) The dramatic increase in the Internet bandwidth available to many users as a result of the proliferation of cable modem and DSL technologies has led to increasing interest in the use of audio and video technologies in Internet-based distance education. Audio and video delivered via the Internet can be used for a variety of educational purposes such as transmitting lectures and demonstrations. In particular, short video clips can be enormously beneficial in demonstrating clinical procedures such as intubation or line insertion. While video files often take up considerable space, audio files usually have much more modest space requirements, depending on the quality of recording delivered. Multimedia files such as audio or video come in two general formats: “downloaded” format and “streaming” format. In the case of the former, the file must be completely received before it can be played, while in the case of streaming files, the material can be played before the material is fully received. Another difference is that downloaded files can usually be saved to hard drive for later use while some streaming formats do not allow the material to be permanently saved so that one can replay them at will. (This “single play only” feature appeals to many music distributors who fear that their material could be spread over the Internet without any restriction such as happened when Napster first set up shop). Sound, image and video files can be uncompressed or compressed, but compression is almost always used when multimedia materials are transmitted via the Web. This is necessary in order to reduce transmission time. Compression can be as much as 90% or more, depending on the technology used. Furthermore, compression can be lossless or lossy, depending on whether or not the original data can be mathematically reconstructed exactly by a reverse operation. Incorporation of multimedia into Web pages is now relatively easy when advanced Web page production packages such as Microsoft Front Page are used. Such packages often allow incorporation of multimedia files using simple “click and drag” methods. This shifts the challenge to that of producing good quality content. A variety of inexpensive audio and video editing tools are available for that purpose. For more information, please consult the information shown in Tables I and II. To see some sample Web-based videos on a variety of anesthesia topics, visit http://gasnet.org/videos/index.php (you will need to download the RealVideo G2 player before you can view these videos).