March/April 2002 // Tools
Delivering Web-Based Multimedia Using CD/Web Hybrids
by David P. Diaz
Note: This article was originally published in The Technology Source ( as: David P. Diaz "Delivering Web-Based Multimedia Using CD/Web Hybrids" The Technology Source, March/April 2002. Available online at The article is reprinted here with permission of the publisher.

Interested in delivering Web-based multimedia to your students? Not too impressed with the quality and function of streaming media? There is another option: CD/Web hybrids.

A CD/Web hybrid, essentially a Web site burned onto a compact disc, can provide a better way to deliver multimedia to the online learner. Though not new, CD/Web hybrids have seen limited use in education until recently (Diaz, 1999). CD/Web hybrids preserve the benefits of both the Web (connectivity and ease of updating content) and the CD-ROM (storage capacity and speed), and provide students with a compelling multimedia experience that may enhance their motivation for learning. The hybrid CD allows teachers to provide media-rich content and realize the full graphical power of the Web (Holland & Haas, 2000).

"Streaming media" (i.e., playing video or sound in real time as it is downloaded over the Internet) is the current rage in Web-based delivery of audio and video. However, the present reality of Web delivery is that bandwidth is severely limited to the majority of the global student population (Klaas, 2001). Thus, the current "state of the art" in streaming media is, frankly, weak at best.

Typical streamed video consists of postage-stamp-sized, grainy, out-of-sync video, that pauses every few seconds to "buffer." Why would teachers want to substitute this miniaturized video in place of a VHS tape or a higher-quality (i.e., high resolution, high frame-rate) digital video? I guess the answer, for many, is "because we can." It may seem amazing to some that it is even possible to stream video and audio. However, many students simply don't have the luxury, or the desire, to spend inordinate amounts of time waiting for large multimedia files to download to their computers, nor will they have much patience for "streamed" video.

Problems Encountered by Online Students

The online environment is replete with time-consuming tasks. Merely logging onto an Internet Service Provider (ISP) can take some time during peak hours and sometimes that connection can be unreliable or just plain slow due to server problems, scheduled maintenance, unscheduled outages, or congestion over data transmission lines. Inadequate connection speeds (i.e., slow modems) also present problems.

Most educational institutions have spent a large portion of their technology funds to create and sustain a high-speed infrastructure. However, concomitantly, PC prices have plummeted making it possible for more and more households to purchase computer systems, including Internet access, which is now ubiquitous and cheap. In non-residential colleges most students are opting to log onto the Web from home. That is, they opt for convenience rather than speed. This convenience includes saving time and mileage costs and avoiding the hassles of arranging Web use around the schedules of lab facilities and staff. This means that our design and delivery of instruction needs to serve this common denominator (i.e., the 56K modem). Though more homes are opting for broadband (i.e., DSL and cable modems) options, according to a recent survey by the U.S. Department of Commerce (2000), only 10.7% of homes with Internet access (4.4% of all U.S. homes) have these broadband connections.

Web design is also a factor, as the complexity of the Web pages themselves can also complicate matters. Scrolling through lengthy pages can take time and patience, especially when multiple graphics are included. And the often-used Java applets can further affect time efficiency. However, by far, the most time consuming aspect of course navigation for online students consists of dealing with high-bandwidth multimedia files. These can come in the form of Flash objects, Virtual Reality files, movies (i.e., Real, Windows Media, QuickTime, AVI), audio (i.e., MP3, WAV, AIF) and other multimedia file types.

Strengths of CD/Web Hybrids

First generation (1 speed) CD-ROM drives were slow by today's standards and yet, these 150K per second drives could transfer 1 megabyte of data (1024K) in about 7 seconds, making the first CD-ROM drives equivalent in speed to a T1 connection (Hallett, 1998). By comparison, today's typical 28K-56K modems take from 3 to 5 minutes to transfer 1 megabyte of data. Current iterations have catapulted drive speeds exponentially. The CD-ROM can match the speed of proposed broadband connections at a reasonable cost, today. This represents a remarkable advantage for the CD/Web hybrid that may offset many of the problems associated with current Web-based delivery of course content.

There are many advantages of the CD/Web hybrid over stand alone educational CD-ROMs and/or Web sites. These include:

  • Speed. The speed advantages of the CD/Web hybrid allow teachers to deliver large, complex multimedia files in an educational Web site without the attendant delays normally associated with the Web.
  • Compatibility. A CD/Web hybrid is cross platform since it employs universal programming languages and file types to deliver content. This also means the hybrid supports multiple browser types.
  • Connectivity. The hybrid CD permits access to a wide range of resources by allowing hyperlinking to the Web and also permits frequent updating of hybrid Web pages.
  • Archiving. Using CD/Web hybrids as a transitional strategy, helps teachers to archive media-rich instructional materials for a future when broadband connections become commonplace.

How to Hybrid

There are different ways that a CD/Web hybrid can be implemented. One approach is to have the hybrid CD contains only those files that require a high-bandwidth solution (e.g., video, audio and graphic files), while the majority of instructional Web pages are served via the Web. This method may require special coding to identify the user's CD-ROM drive letter, assign that drive letter as a variable in HTML and then use that variable to call images and movies from the CD-ROM. An overview of this method and sample code can be found on Dr. Reid Holland's excellent CD/Web hybrid informational Web site.

My use of CD/Web hybrids has spanned several years as both an adjunct to face-to-face classes and as a primary delivery mechanism for online classes. In my implementation of the CD/Web hybrid, I put as much of the Web site as possible onto the CD. In this way, I am delivering all of the high-bandwidth files as well as all other static, or semi-static, content pages. This approach has the advantage of allowing students to use the hybrid CD without having to be logged onto the Internet. This can be a time saver in online classes and a major convenience when students are using computers not connected to the Internet. The only pages that are actually "hybrids" are those that have information that is likely to change in the short term (e.g., syllabi, grades, etc.). My early research on CD/Web hybrids has been published (Diaz, 1999) and is available online.

In practice, the hybrid CD causes the CD-ROM and the Web to interact simultaneously. Students can access high-quality video and other content-based features while also gaining instant access to the rich resources of the Web. Interactivity can be provided through links to listservs, message boards and other synchronous or asynchronous technologies.

A teacher still needs to design thoughtfully and reject too much passivity in the delivery of instructional content. Video lectures and demonstrations must be kept brief. Remember, we take for granted the interaction and discussion that is "sandwiched" between the content portions of a typical classroom lecture. On the Web, a lecture can become too passive from the student perspective. Thus, lectures must be condensed and the key points distilled. Students should not be made to endure 50 minutes of video, but rather, lectures should be limited to brief conceptual pieces.

Video is a great medium for presenting brief lectures, digital portfolios, demonstrations (e.g., how to use a pottery kiln, or how to stretch) and illustrations/animations (e.g., chemical reactions). Short snippets of VHS, Hi-8, or Digital Video (mini-DV) tapes can be "digitized" or imported to computer hard drive to create instructional digital videos. Disciplines that use video frequently, for example athletics or performing arts, will have huge quantities of "raw material" for digital video. In another implementation, typical multimedia presentations (i.e., PowerPoint) can be narrated and then exported as a movie file (requires Office 2000 or later for Windows, or Office 2001 or later for Mac). This represents a familiar context and platform for the creation of instructional videos.

When to Hybrid

Streaming media can be useful in some instances and, ultimately, the current bandwidth limitations will be solved (although probably not as soon as ISPs would like us to believe). Since neither streaming nor hybrid CDs will work for every situation, what criteria should determine their use? Streaming media can be considered if your campus is a residential one and most of your students live on campus, and if those residential students have "just-in-time," "just-as-needed" access to high-bandwidth connections. I say streaming can be considered, because there are some types of streaming applications that are not ready for even a fast Internet connection. For example, downloading class plug-ins or ancillary software would be easy and efficient over a fast Internet (e.g., Internet 2 or mega-bandwidth intranet), while streaming of video may be less than acceptable. Even a high-bandwidth infrastructure can experience delays during peak times. Delays are not conducive to the delivery of instructional content and will probably require a down-sampling of data files and result in less-than-desirable quality.

Ultimately, it's a numbers game. If you have enough students that can access the campus high-speed infrastructure, then perhaps streaming may be a better option than CD/web hybrids. The purchase, development and distribution of CDs can present their own share of difficulties and there are copyright considerations when distributing media on a disc. The actual needs of instruction must determine whether delivery of streaming files is adequate. If streaming is not adequate for instructional needs, then CD/Web hybrids should be considered and copyright and other important issues should be dealt with head on. Downloading software and plug-ins can suffer momentary bandwidth restrictions and congestion without disrupting "service quality" to the student. If this is the case, Web-based delivery or delivery by CD-ROM would be equivalent. However, delivering instructional video requires sustained transfer speeds for acceptable playback of content. If the typical student Internet connection is mediated by an analog modem, the CD/Web hybrid should be a favored solution.

The use of CD/Web hybrids can be a perfect interim strategy for delivering high-quality multimedia content until bandwidth concerns have been alleviated. Hybrid CDs can allow teachers and trainers to deliver compelling multimedia content via an instructional Web site.


Diaz, D. P. (1999) CD/Web Hybrids: Delivering Multimedia to the Online Learner. Journal of Educational Multimedia and Hypermedia 8(1) 89-98.

Hallett, P. (1998, March). CD/Web hybrids: best of both worlds. Emedia, 11, 40.

Holland, R. A. and Haas, J. (2000). Delivering media rich Internet courses while overcoming bandwidth limitations, in Exemplary Practices in Information Technology. League for Innovation in the Community College, Mission Viejo, CA.

Klaas, B. (2001). Streaming media in the last mile. Paper presented at Syllabus Summer 2001. Retrieved July 27, 2001 from the WWW. Available:

U.S. Department of Commerce. (2000). Falling through the net: Toward digital inclusion (NTIA Publication). Retrieved October 4, 2001 from National Telecommunication & Information Administration (NTIA) Web site:

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