Writing for the Web: A Primer for Librarians

by Eric H. Schnell

Multimedia

The use of multimedia within Web documents is becoming the major focal point of Web development. This is because the Web is a natural medium for the distribution of media-based information resources across computing platforms. In addition, creating Web-ready media resources has become simpler as development and conversion tools continue have evolved.

Multimedia materials referenced on Web documents often can not be played back within the Web browser itself. Instead, when a browser encounters a media format it can not display it looks for a helper application appropriate for the format. Newer Web browsers are now being developed with many of these helper applications built in, however, most media formats can be supported by adding media viewers as plug-ins.

A concern about helper applications is the need to download the entire file to begin playback, requiring a great deal of time. This has begun to change with the concept of media streaming, or real-time media playback. Software such as RealPlayer allow the user to begin playing the audio file as it is being received. Although this type of product shows great promise in the delivery of multimedia information, bandwidth and network traffic can slow transmission rates.

Video

The primary video formats and MIME extensions used on the Web are MPEG (.mpg) and QUICKTIME (.mov). The size of video files required with these two formats is of a major concern for Web authors. It is not uncommon for a 30 second video file being several megabytes in size even after file compression.

video example This is an example a link to video of a Space Shuttle Launch. (format: MPG; Size: 800k).

Downloading a file this size over a modem could seemingly take forever. As with audio, there are several products currently available in the area of realtime video streaming. Products such as VOSAIC and CineWeb, and Shockwave are available.

The size of the viewing area for most video software is small, maybe a few inches square. Transmitting video files large enough to take up a whole monitor would be enormous and would take up even more bandwidth. These factors may be causing many Web site developers to wait for integration of video until the technology advances another generation, or two.

The inclusion of video on library Web pages has also been quite limited. As with audio, finding appropriate applications within the library setting may be the major reason for limited video integration. The lack of production facilities and technical staff to produce and convert visual information for the Web could be an additional reason. Potential library uses for distributing video on the Web could be the delivery of instructional videos and remote tours of library facilities.

Audio

The most common audio file formats and their MIME extensions are -law (.au) and WAVE (.wav). The single greatest reason for their popularity is cross-platform compatibility and availability of player software. An in-depth technical discussion of distributing audio on the Internet is covered in the Web document Audio on the Internet, written by Victor Lombardi at New York University as his graduate thesis.

audio example This is an example of using an in-line image to link to an audio file. (format: WAV; Size: 393k)

Practical applications for the use of embedded audio files into library Web documents are quite limited. As a result, few library Web sites currently utilize audio. Potential uses including the delivery of recorded lectures, oral histories, and live events. Beyond limited practical applications, there are other reasons for limited use of audio. Creating audio resources into Web documents requires technical skills. Not all libraries have staff with media production skills. In addition, converting audio from a tape medium into a digital format, or recording it digitally, requires specialized hardware which few libraries can afford to support.

Synchronized Multimedia Integration Language (SMIL)

Using only simple HTML-style markup tags, SMIL allows Web authors to schedule and choreograph sound, video, text, and other elements on a Web documentpage. Previously, Web architects looking to create vivid multimedia experiences needed to master complex scripting schemes -- such as JavaScript, Java, or Dynamic HTML -- or development tools.

SMIL aims to change this by utilizing a handful of simple instructions and a text editor. Authors will be able to layer audio, video, and text on a site or a page by choreographing which media files to "play" when and for how long.


For More Information:

Lombardi, Victor. Audio on the Internet.

The World Wide Web Organization. Audio, Video, and Synchronized Multimedia

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Page Updated: Tuesday, 24-Nov-98
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