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Introduction to Streaming Media for Educators
'Why not squeeze some teaching and learning
into our student's fascination and infatuation with the new features
of the broadband Internet'?
Author: Dominic Camardella, Multimedia Technologies
Audio and video streaming has become the newest
wonder application on the Internet, and as educators we benefit
whenever we utilize these innovative and useful applications of
new technology.
It is essential to explore and utilize streaming
audio and video and web broadcasting and to think about the ways
to incorporate the support and features of on-line streaming content
into your courseware. It is sure to truly stimulate and expand
your student's interest in your course content.
Streaming media on the web utilizes a server technology
where audio and or video content is sent to the visitor's computer
in an 'as needed' basis. In the past a web visitor would have
to wait for a complete download of a media byte before viewing
the content. These downloads could take minutes, and would generally
provide just a short snippet of content. Now, by using streaming
media, we are no longer restricted to short presentations that
must be totally transferred before viewing, but rather can provide
much longer on-demand content that can be clicked on when the
student wants to see it.
Video clips of class demonstrations can be uploaded
to the streaming server and students can review these clips at
any point during the semester. Selected course supplements that
are already available on videotape can also be made available
to review from the web as needed. Lectures can be videotaped and
archived for student access at the end of semester. Students that
have missed a class lecture can have the benefit of accessing
the content covered in class. Special subject matter covered in
lectures given by experts in their field or discipline can be
archived for viewing in class or from home so as to enrich the
diversity of subject matter available to students.
Why Streaming Media?
- Using streaming video and audio can enhance and
revitalize an otherwise dull topic
- Students learn visually by seeing examples and
uses of what may be difficult to grasp when read
- Some students pay more attention to an audio
or video presentation
- Students like the opportunity to diverge from
traditional learning methods
- Students take every opportunity to use the web
as a resource for learning
- Students enjoy using the web as a resource for
learning
- Students find web streaming exciting and fresh
- Students are more willing to put up with
the technical limitations of their web connection
FAQ's: (Frequently Asked Questions)
What is streaming media?
Streaming media is audio and video clips that have
been encoded and made deliverable via a specialized network media
server that delivers the content to the desktop on an as needed
basis. With streaming media there are no long waits while large
files download to the user's computer, only a short buffering
period that is usually a matter of seconds before the file begins
to play.
What companies are the leaders in streaming media and now make
this technology available?
There are three main companies involved with streaming
media. Real Networks provides the Real Server, Real Producer,
and Real Player along with additional tools for streaming slideshow
presentations and also PowerPoint presentations. Microsoft offers
the Windows Media Server as part of its NT Server Suite of technologies,
and this system uses the Windows Media Player that is included
with every Windows operating system sold for the player utility.
Also, Apple Computer now offers QuickTime as a solution that has
recently entered the streaming marketplace and this technology
uses the Apple QuickTime player and server for delivering and
accessing content.
The Real Networks solution has become the most widespread
of the three, and offers the broadest compatibility with different
computer types and operating systems. Recently it has added the
ability to stream QuickTime movies, MP3 Audio, as well as JPEG
and GIF still image slide shows synchronized to an accompanying
audio stream (REAL calls this SMIL-synchronized multimedia integration
language).
Video and Audio files are very large, how is this accomplished?
For a number of years now computer scientists and
software engineers have consulted with physiologists to better
understand the mechanics of how we humans see and hear media.
The result of these studies have led to the development of what
are now called 'perceptual' encoders that compress the file sizes
of audio and video data by smartly discarding the information
that is less relevant to the eye and ear.
One example of this is the CODEC (encoder-decoder)
that is used to prepare MP3 audio files which have now become
the 'de facto' standard interchange of audio files over the Internet.
Even professional audio people are surprised by the audio quality
of MP3 audio where the size of the files are often 10% of the
original file, but the apparent perceived quality of the audio
comes close to 90% (or better) of the original audio. This is
why the record companies are so threatened by Napster.
What are the components of a streaming
media system?
There are four main components of such a system:
- the audio/video workstation where the media is
edited at full resolution and the streaming media encoder software
is installed to compress the finished edited video and audio
into server ready media bytes or files
- the web server or intranet (local network) server
where the access to the library and selection of files available
for streaming are indexed and available for clicking on-demand
(when we want or choose to access this content)
- the streaming media server which is a specially
configured machine that has the streaming delivery software
installed and is equipped with a large amount of storage to
house the entire contents of the media library that is accessible
for streaming; the streaming server receives requests from the
web server that indicates what file needs to be delivered and
to what user
- the client/user browser application is a typical
web compatible computer with audio/video playback capability
that has the appropriate player application installed to facilitate
viewing and listening to streaming media content (examples:
Real Player, Windows Media Player)
What kind of connection to the Internet
or local area network will I need?
Often streaming media developers tailor the content
for various levels of connectivity. So if you are connected via
a 56k modem, DSL connection, or campus Ethernet, when you visit
a streaming media web site that has media archives available,
you would select the files for streaming that matched your particular
connection environment. DSL connections typically can handle content
up to around 150Kbits, where as a campus based Ethernet might
allow you to view content encoded at up to 500kbits or better.
If you experience inconsistent playback or frozen video frames
you should select the next lowest bandwidth level offered at that
respective web site.
How do I use streaming media in my courses?
This can vary greatly depending on what type of
course you are teaching, and what materials are already available
to you on video or as audio that can be re-purposed for streaming
media use. Often, multimedia departments beginning at the community
college level already have the basic ability to encode audio or
video for streaming. The basic software technology for this is
usually offered free of charge by the companies marketing their
server solutions and also advanced encoding applications. In some
cases you can actually purchase computers with video and audio
capture and editing capability very cheaply and simply add the
encoding software.
Once the content is prepared (remember, practice
makes perfect!), you will need access to a streaming server and
also a web server to upload the index of media bytes and actual
audio and video media clips that you will want available for streaming
delivery.
Contact the webmaster at your particular school
and recruit their assistance. It is their job to aid and assist
in the implementation of these kinds of new technologies. Sometimes
the streaming server will not be available from the college's
server system, and there are numerous third party companies that
specialize in the delivery of streaming media as a service.
What kind of viewing experience can I expect
at various bandwidths?
Well, for viewing video the lowest speed connection
is a 56k modem. At this connection speed the dimensions of the
player's window size needs to be reduced to around 192x144 pixels.
As such, this bandwidth is most suited to talking head lectures
or content that presents modest detail on the screen when viewed.
Remember that if the audio is of sufficient quality in a talking
head type of scenario, the message of the content will usually
be received just fine! As the connection speed reaches or exceeds
100kbits, the dimensions of the player's window size for the presentation
can become 320x240.
As the bandwidth goes well beyond this threshold
the smoothness of video playback become very television like.
In very low bandwidth scenarios consider using high quality still
images that are streamed in conjunction with an audio stream for
the presentation (REAL Network's SMIL technology). Numerous specialty
multimedia developers are cropping up in every community around
the country to provide the service of media encoding and delivery
for distance learning applications that utilize streaming media.
What are the limitations of this technology?
Basically this technology is constrained by the
available connection speeds and bandwidth available to the server
and client users. On the server side, we must provide for enough
bandwidth for the cumulative number of simultaneous user connections
to our streaming media server. For example, if we have media bytes
stored on the server that require a 100kbit per second connection
to view the stream over the Internet, fifteen simultaneous viewers
will utilize 1.5Mbits of bandwidth leaving the server. This is
equivalent to a T1 line.
Although most college campuses have a minimum of
a T1 line or better for their connection to the Net, this connection
is usually intended to serve all the Internet needs of the campus.
So, even a modest distance learning scenario that intends to deliver
content via the Internet will require a fractional T3 line, and
so it is wise to first consult with your campuses' network infrastructure
organization before embarking on an aggressive program of distance
learning using streaming media. Generally on-campus we are interconnected
by Ethernet capable of delivering 100Mbits of information per
second and are less constrained than if we need to deliver the
content to the Web.
As to the client side issues, once we have addressed
sufficient bandwidth for quality delivery from the server to the
Internet, we need to look at the quality as perceived by the viewer.
Television video presents 30 frames of information per second
to construct smooth motion, but over the Internet, we typically
achieve no more than 15 frames per second.
It is essential to take note of this and understand
that video with a high degree of motion will be jerky at best,
and also when viewing video that includes numerous subtle effects
will often result in omission or unacceptable delivery of these
kinds of nuances. Web video needs to be prepared to allow for
a 'graceful' deterioration and degradation of quality and this
is why a whole category of specialists that re-purpose both audio
and video media for streaming usage are now available and providing
this service.
More than ever, remember the notion of 'garbage
in' equals 'garbage out'. It is essential that streaming media
begin with a high quality master source to insure the integrity
of the results.
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