Papers in PDF format

Overview:
Automatically Generated Web-based Multimedia Presentations
Dr. Richard L. Klevans
Department of Computer Science, North Carolina State University
Box 8206, Raleigh, NC 27695, Email: rlklevan@eos.ncsu.edu, Telephone: 919-515-6535
Dr. Mladen A. Vouk
Department of Computer Science, North Carolina State University
Box 8206, Raleigh, NC 27695, Email: vouk@adm.csc.ncsu.edu, Telephone: 919-515-7886
Using existing technology, such as Web browsers, HTTP servers, HTML documents, CGI programs, and
RealAudio, we have developed a system for automatically generating and serving low-bandwidth Web-based
multimedia presentations based on live versions of the same presentations. This system has many potential
uses such as delivering distance education through on-demand lectures, and capturing conference presentations
and making them available to wider audiences.
To make these presentations available via the Internet to the widest possible audience, a low-bandwidth
solution is necessary. A presentation, whether it be a lecture in an educational setting or a presentation at a
conference, typically involves of a person who talks about a set of slides or transparencies. Most of the
information is in those slides and in the presenter’s speech. The image of the talking head contains little
information relative to the content of the presentation. Hence, high-bandwidth video is often not required to
successfully transfer the presentation information. We useHTML
versions of the slides and the accompanying
audio to reduce bandwidth but still retain a high percentage of the original presentation information.
Synchronized audio with automatic page turning is used to simulate the original presentation as closely as
possible. However, when the situation demands it, we also use high-bandwidth video clips. A user can watch
our presentations in a hands-free fashion, but he/she can also “stop, pause, rewind, and fast-forward “ the
presentation in a “recorder/player-type” fashion.
In order to minimize the effort required to transfer presentations onto the network, tools for automatically
generating the Web-based presentation from the original presentations are necessary. One key piece of
information is the timing data that describes when to advanceto
the next slide (or backtrack to a previous one).
Our system provides mechanisms for automatically capturing the timing for the slides as the original
presentation is being delivered, or in a post-processing mode if the system was not used during the original
presentation.
Design Platform:
One of our goals is to make the presentation information available to as wide of an audience as possible . In
order to do that, we found it necessary to use only existing and readily available technology. Standard Web
browsers and HTML documents were a natural choice. To allow delivery of the presentation slides in multiple
formats, such as with or without frames, each slide’s content is kept separate from the control links that permit
navigation through the lecture—e.g., the “Next” and “Previous” buttons.
For the audio portion of the presentation, we have chosen the RealAudio format for several reasons.
RealAudio servers can transmit high-quality audio in a streamed fashion with minimal start up cost
(Typically, 5 seconds or less). By “streamed” audio, we mean that the entire audio file need not be downloaded
to the client’s machine before the audio starts playing. Due to the high compression rate of the RealAudio
format, the required disk storage space and network bandwidth are minimized. Even clients with 14.4 Kbps
modem connections can successfully receive RealAudio files. RealAudio also provides a mechanism for
triggering the client’s browser to display a sequence of HTML pages based on time stamps. This give s the
user of the system the illusion of being at the actual presentation as the slides automatically advance when the