Experiences with real-time streaming audio/video in delivering Web-based courses
Thomas I. M. Ho
WebLab
http://weblab.iupui.edu
Indiana University Purdue University Indianapolis
Abstract
Over two years of experience with the application of real-time streaming audio and video
(RealAudio/Video) to Web-based courses has yielded a wealth of experience in
synchronous delivery of live instructional content and asynchronous delivery of archived
content. Outcomes include:
1. Live broadcast
a. Audio/video lecture content
b. Visual aids “pushed” to remote viewers
c. Chat feature for remote audience participation
2. Archived lectures with the soundtrack synchronized with the Web pages displayed
during the live lecture (Synchronized Multimedia)
3. Multimedia annotations of Web page links including:
a. Explanation of examination questions and answers
b. Motivational messages to explain Web pages
c. Oral instructions for assignments
An example of a course with these features can be found at:
http://oncourse.iupui.edu/courses/scripts/detail.asp?course=1998%2D1%2DIN%2DCPT%2D499%2DB554
(log in
as guest)
Products of this experimentation include:
1. User interfaces for:
a. live broadcast
b. archived lectures
2. Productivity tools for:
a. constructing Synchronized Multimedia content
b. creating voice annotations
3. Economical classroom premise equipment for originating live broadcast and encoding
archived lecture
What is RealAudio/Video?
The RealNetworks Basic Server, RealEncoder, and RealPlayer comprise the RealMedia
System created by RealNetworks (1997). The RealNetworks Basic Server streams files
created with the RealEncoder to free RealPlayers on sound card-equipped personal
1
computers, which continuously decompress the audio and play it in real time without
download delays, even over 14.4 Kbps modems.
RealAudio has been widely deployed on the World Wide Web especially to distribute news
and music as described at the RealGuide (1998) site guide. More recently, RealVideo has
added video capability to RealAudio within the RealMedia architecture. Educational
applications have become more common and examples can be found at RealNetworks’
(1998) education page.
Experiments with RealAudio
Beginning in September 1996, Introduction to Data Processing (CPT 115) broadcast
lectures live from Indiana University Purdue University Indianapolis (1996) via RealAudio.
Figure 1 is a diagram describing how the live broadcast was done. In addition, the lectures
were archived on the Web site. As a result of this audio content being available, the Web
site was significantly enhanced by the addition of voice annotations and oral instructions
for assignments. Voice annotations were used to provide motivational messages to
explain Web pages such as the one at:
http://www.engr.iupui.edu/cpt/courses/cpt299/1997fa/it/itaids.html
During the Spring and Fall 1997 semesters, Internet Skills (CPT 299) at Indiana University
Purdue University Indianapolis (1997) continued the experiment by using Synchronized
Multimedia to synchronize the lectures with visual aids on Web pages. Most of the
lectures on: http://www.engr.iupui.edu/cpt/courses/cpt299/1997fa/tcs.html have been synchronized. An
example of Synchronized Multimedia by Thomas I. M. Ho (1997) explains this experiment
in greater detail. To experience it, one will need:



A personal computer with sound card
An Internet connection with a speed of 14.4 Kbps or better
RealPlayer 5.0 (free to download from the RealNetworks Web site at www.real.com)
In addition, voice annotations were used to explain examination questions and answers
on: http://www.engr.iupui.edu/cpt/courses/cpt299/1997fa/tcs.html
2
Figure 1. Originating a live broadcast via RealAudio
Experiments with RealVideo
Beginning in January 1998, Electronic Commerce (CPT 499) broadcast lectures live from
Indiana University Purdue University Indianapolis (1998) via RealVideo. Origination of live
broadcast and archiving were accomplished via the ClassCast project developed by the
WebLab (1997). Figure 2 describes ClassCast’s improvements to the original live
broadcast environment described in Figure 1. In addition, the archived lectures were
significantly enhanced by the addition of “highlighting” which draws the students’ attention
to lecture segments that the instructor emphasizes because they are important and likely
to be tested in examinations. A red bar that appears above the visual aids that are
synchronized to the sound track indicates highlighting. As a by-product of these
“highlighting” events, the important segments are indexed in the archived lectures so that
these segments are then subsequently hyperlinked to the correct responses in the
examination key so that the student can play back the video clips in which the answer to
the corresponding examination question was given. RealVideo requires an Internet
connection with a speed of 28.8 Kbps or better.
3
Figure 2. ClassCast environment for live broadcast
Results of experiments
Products
The major products of this experiment include:
 User interfaces
 Productivity tools
User interface for archived playback
The primary user interface has been developed for playing back archived lectures
synchronized to the Web pages displayed during the live lecture. An example at:
http://weblab.iupui.edu/cpt/archive/archive.asp?course=499&sem=fall1998&sec=B554&da
te=0923&start=1:0.0&end=01:19:0.0
demonstrates the controls for the video/soundtrack with a frame for displaying the
synchronized Web pages and another frame for displaying the highlighting visual cue.
4
User interface for originating live broadcast
The live lecture is broadcast to remote viewers via the ClassCast user interface with the
following capabilities:
 Delivery of audio/video content
 “Pushing” Web pages displayed to students in the classroom
 Chat to enable remote viewers to ask questions and to participate in classroom
“discussions”
A notable contribution of the ClassCast user interface for the instructor is its ability to
“time-stamp” each mouse click while “pushing” Web pages to remote listeners. This
capability has greatly facilitated the creation of event files for producing Synchronized
Multimedia versions of the lectures for archived playback!
Another notable outcome is the fact that an ordinary classroom was equipped with the
ClassCast originating equipment for only about $20,000! For this modest amount, this
classroom can serve a global audience!
Another capability developed by the WebLab (1998) is NetCast which enables RealAudio
content to be originated (broadcast live and archived) from anywhere via telephone. This
capability is convenient for originating lectures from home when the instructor is ill or even
for delivering conference presentations at remote locations without traveling to the
conference venue. Although NetCast is conceptually similar to the original RealAudio
origination capability depicted in Figure 1, NetCast has the additional capability of
scheduling the encoder via the World Wide Web as well as equipping the encoder with
“auto answer” rather than requiring human intervention to answer the phone when initially
connecting to the encoder.
Experiences
This experiment has demonstrated that significant instructional content can be delivered
via real-time streaming audio and video that can be received by a modest computing
platform with no more than a 28.8 Kbps dial-up connection to the Internet.
An anecdote serves to remind us why it is so important for us to experiment! Our
experiments with RealVideo have led us to consider whether RealVideo can be used
practically to broadcast signing to reach deaf students. Remember that we first
experimented with real-time streaming audio to enable us to reach students who could
hear!
References
Ho, Thomas I. M. (1997) How We Do RealAudio [WWW document] URL
http://weblab.iupui.edu/ho/cpt299_f97/lecture_frame.html?101797
Indiana University Purdue University Indianapolis (1997). Internet Skills (CPT 299), Fall
1997 Web site [WWW document]. URL http://www.engr.iupui.edu/cpt/courses/cpt299/1997fa
5
Indiana University Purdue University Indianapolis (1998). Electronic Commerce (CPT
499), Web site [WWW document]. URL
http://oncourse.iupui.edu/courses/scripts/detail.asp?course=1998%2D1%2DIN%2DCPT%2D499%2DB554
(log in as guest)
RealGuide (1998). Web site [WWW document]. URL
http://www.real.com/realguide/index.html
RealNetworks (1997). Web site [WWW document]. URL http://www.real.com
RealNetworks education page (1998). Web site [WWW document]. URL
http://www.real.com/solutions/classroom/casestudies/index.html
WebLab (1997). ClassCast, [WWW document]. URL
http://weblab.iupui.edu/projects/ClassCast.html
WebLab (1998). NetCast, [WWW document]. URL http://netcast.iupui.edu
6