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Adding Streaming Media (Audio and Video) to Your Web Site
You may have
seen audio or video used effectively on the web, and want to add some
to your own web site. This can be especially effective if
you are teaching online and do not ordinarily speak
face-to-face with your students. What is
missing from some online classes is the direct expression of
learning cues from professor to student. These can and are
delivered in print, of course, but they can become much more
meaningful when they are heard in an audio file or even seen and
heard, emphasizing the professor's body language, in a video file.
Streaming Media
Examples from Palomar College
Though the process can seem daunting at
first, it is only moderately difficult once the
initial concepts are understood. At Palomar
College, there is in-person help
available to Palomar staff all along the
way through the Academic Technology department.
We will be glad to help you produce and mount your
media project. If you wish to do it yourself, however, be aware
that any media work, especially the initial recording of the media,
requires patience and practice. This page is a beginner's guide
to adding audio and video, primarily streaming audio
and video, to your web
site. If the discussion seems far too technical, call us (ext.
2877 - tgray@palomar.edu) and
we will help you with your media projects.
In broad outline, there are
the four basic steps:
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Create your digital media.
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Encode your media for a
streaming server.
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Mount the media on a
streaming server.
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Link to the media from a
web page.
Click here to see a diagram of the
process.
The following provides
details, but is by no means an exhaustive discussion. It assumes the PC
platform and the Windows operating system, though Mac and Mac alternatives
are discussed.
Analog vs. Digital
Create the media you want
to place on the web. This means that you must either:
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Transfer pre-record media to a computer, for
example, music from a CD or cassette tape, video from a VHS tape or
captured from a television show.
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Record your own media from
scratch, for example, videotape yourself with a camcorder or record
yourself speaking into a microphone.
Your source recording will
either be in digital or analog format. If analog, like a VHS video
tape or sound recorded on a cassette tape, it must be converted to a
digital format before it can be placed on the web. Special hardware
is required to make this conversion. In the case of audio files, the
sound card already installed in your computer is probably capable of doing
the job. In the case of video, a special video capture card is
required.
In addition to hardware,
software is also needed to convert analog to digital. With audio
files, there is a good, free alternative, but with video, the software
required will usually come with your video capture card, or can be
purchased separately.
On the other hand, if your
media is recorded digitally in the first place, like from a digital
camcorder or audio spoken into a media recorder on your computer, it is
not necessary to convert it further, though it may be necessary to use
software to edit it. In the case of audio, an original digital recording will yield far
better results, and generally be much easier to work with, than a
recording converted from analog to digital. With video this is also
true, but to a lesser extent.
The idea with capturing or
recording media files is to get them into an uncompressed, or raw, digital
file format, which can then be compressed--in order to reduce their
size--for the web. For video files, this will either be an AVI or
MOV format; for audio files, either a WAV or AIFF format. This discussion will concentrate on the PC world, so it
will discuss Microsoft AVI and WAV formats. Remember, AVI files
store uncompressed video data (usually comprised of both video and audio
tracks), and WAV files store uncompressed audio data. These files
can be enormous, especially in the case of video files.
Creating these initial
files is by far the most difficult part of the process, especially if
editing is required and you are combining multiple files into a single
file. There is no substitute for practice with your software of
choice when doing this. If you want to edit video files,
Adobe Premiere is the Cadillac
editor (at least in any normal person's price range), but there are many
low cost alternatives--usually those that come bundled with video capture
cards. The question to keep in mind when picking a video editing
program is: can the program read and write uncompressed AVI files?
If so, you won't have any trouble preparing files for the web.
You will also need a large hard drive
to work with video.
Uncompressed video files are very, very large.
Audio editing programs are
much more affordable.
SoundForge FX is a good, low
cost (about $60.00) program that will do everything you need. Audio,
on the other hand, usually requires less editing than video, and is, in
general, much easier to work with. A free program like
MusicMatch Jukebox may be all
you need to create and convert good, digital audio files. When
recording digital audio, the microphone is the most important component.
If you are recording yourself speaking into your computer, setting the
sound level on your computer is also important.
Finding the right set up takes some.
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Detailed Example:
Click here for screen shots and explanations on how to record yourself
digitally using MusicMatch Jukebox. (This page includes a section on
how to set recording volume levels in Windows). |
Compress Files for the Web
Once
you have a finished, uncompressed digital master
file--either an AVI format video file (which, in fact contains both video
and audio tracks, in most cases) or a WAV format audio file, you could
place this file on your web site, link directly to it, and when your users
click on the link it would invoke the associated media player, download
the file, and play it. In all likelihood, this would be such a
painfully slow process, even with a relatively short audio file (unless
the recording is extremely short--say a couple of seconds) that your users
would lose interest and cancel the operation. This is because of the
enormous size of the original, raw files. In order to reduce their
size, and prepare them for mounting on a media server, they must first be
encoded. Only encoded files (that is, files compressed using a
codec--or,
code/decode algorithm) can be streamed.
The purpose of encoding is
to greatly reduce the media file's size, and to prepare it for efficient
use of a streaming server. Encoded files can be linked directly from
web pages, and downloaded and played much as raw AVI or WAV files can, but
this is not the same as streaming. It will occur more quickly for
your users than will the raw-file scenario described above, but still not
quickly enough, and will probably be jerky and unreliable. True
streaming is done from a specialized streaming server that uses
fast, real-time Internet protocols and retains two-way communication
with the media player, feeding it as much of the stream as it needs to
proceed. The three most popular types of streaming servers are:
Microsoft media
Real media
QuickTime
QuickTime files can be
streamed from an advanced Real server.
Which is the best format?
Good media players for all three types of servers exist for both the PC
and Mac platforms. Let's be practical, though. Market research
indicates that approximately 65% of Internet users have installed the Real
media player as their primary media player, 21% the Windows media player,
and 14% the QuickTime player. These numbers are always in flux, but
give an idea of the "market" out there. It is probably true
that most users have both the Windows Media player (it comes with recent
versions of Windows) and the Real player. Many also have the
QuickTime player, but it is definitely less popular. To reach the largest
audience in the format they are most comfortable with, it makes the most
sense to stream for Real media. On the other hand, since Real uses
proprietary codecs, and since Real servers have a restrictive licensing
policy, and sometimes do not get along with
firewalls, it is also a good strategy to stream for Windows media.
Windows media servers are based on open standards and do not usually have
problems with firewalls--at least in Windows server environments.
Because QuickTime files can be streamed from a Real server, and QuickTime
users tend to be Mac users also--a very small percentage of the at-home
market--we do not support QuickTime as a dominant format at Palomar
College. This discussion will concentrate on Real and Windows media
formats from here on.
So how does encoding
happen? The easiest way to encode a media file is to load it into a
video or audio editing program that has built-in plug-ins to encode using
one of the popular media formats: Windows media or Real media. A
program like Adobe Premiere
or
Pinnacle Systems Studio 7 have such plug-ins.
A stand alone program, like
Terran Media
Cleaner, could also be used. It is a sort of all-in-one
program than can be used to encode many formats--though its performance is
quite slow.
If you do not wish to use a
for-pay option, the software tools for encoding media files can be
obtained free, if you are willing to learn how to use them. If you
wish to encode files for Windows media format, you will need the
Windows Media Encoder. The Windows media encoder is based on
open standards and supports many freely available codecs. If you
wish to encode for Real media, you will need the free
Real
Producer Basic. Real media encodes for the proprietary Real
media format.
Before encoding, a key
decision must be made: what bandwidth target do you want to achieve?
A bandwidth target refers to the speed of the connection your user will
have to the Internet. A high bandwidth target, such as a corporate
LAN or home broadband access to Internet through DSL or cable connection
can support a larger video picture and higher quality audio than can a
limited bandwidth target, such as a 28.8 modem. As a general rule,
this is only truly relevant with video files, not audio files. High
audio fidelity can be achieved in bandwidths as low as those aimed at the
28.8 modem user (though most users these days have at least a 56k modem).
Not so with video. A video file, even an encoded video file,
requires a lot of bandwidth. Only the smallest, postage-stamp sized
video window with a very low-fidelity sound track can be aimed at such a
narrow bandwidth target. For all practical purposes, video at modem
speeds can be done, but be prepared for low quality. The Windows
media encoder comes with many pre-sets from which you can choose to help
you choose a bandwidth target. Since Real uses proprietary codecs,
its choices are fewer, but both are easy to understand and customize, if
need be.
Once encoded, your original
raw AVI or WAV file will become a WMV (video) or WMA (audio) file, if you
have encoded for Windows media; or a RM (video or audio) or RA (audio)
file if you have encoded for Real media. If you look at the file
size, you will notice that it is dramatically smaller than the original,
uncompressed file.
Even encoded files can be linked and played directly from a web server,
using http protocols, but this is not the same as streaming them.
This is still a download and play scenario which, because the file sizes
are much smaller, will occur more quickly, but not as quickly or reliably
as true streaming.
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Detailed Example:
Click here for screen shots and
explanations on how to encode a WAV file using Real Producer Basic. |
Streaming Media Servers
To achieve true
streaming, an encoded media file must be mounted on a streaming media
server. It is the media server's job to use
special real-time protocols and control techniques to stream multiple
instances of your file over Internet in a very efficient manner.
Palomar College Academic Technology supports two streaming server
formats, Real and Windows media. The process of mounting your file
is simple, and it is the same for both. First, use our
web request form
to request a personal folder on one or both of our servers.
We will email you the details of how to access your
folder. Usually, we recommend you ftp your encoded media files to
your personal folder(s). If you do not have an ftp program, we
recommend the simple to use
WS_FTP
client program. The following is a download link for this PC program:
WS_FTP Download
Once you have
moved your encoded file to the streaming server, you are ready to create a
link to it on a web page.
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Detailed Example:
Click here for screen shots and
explanations on how to
ftp your file using WS_FTP. |
Invoking or Embedding the Media Player
There are two
ways to link to an encoded media file on a Real or a Windows media server:
So that the
file will be played in a stand-alone instance of the media player, which
is invoked when the user clicks on the link on your web page.
So that the
media player is embedded in the web page, and when the user clicks on the
player control, embedded on the page, the media plays, pauses, stops, and
so on.
The easiest
method, and the one with the most advantages, is the first, though there
are specific times when the second is the better choice.
Because embedding is so technical, it is only briefly discussed below.
In
the first instance, invoking the stand alone player, you link to a
redirector file, which in turns invokes the media player and starts the
stream. With the Windows media player, this is known as a WVX
(video), WAX (audio), or ASF (older video or audio formats) file. It
is a simple text file containing XML commands that control the playing of
the media. With Real media, this redirector file is known as a RAM
file (or RPM file if linking to an embedded player). Examples are
provided below.
A Windows
Media Metafile
To link to a Windows media
file, you must create a redirector file to the media. A WVX, WAX or ASF file
should be created in a simple text editor, like Microsoft Notepad.
The following is a very simple example: <ASX version = "3.0">
<Entry>
<Ref href = "mms://venus.palomar.edu/path/MyFile.wmv" />
</Entry>
</ASX>
Metafiles
use an XML-based scripting language. In this example, the metafile
simply instructs Windows Media Player to play one file from the Windows
media server "venus.palomar.edu,"
in the path (assigned when you request it from
Academic Technology), named MyFile.wmv.
The wmv extension means it is a Windows Media Video file. Audio
files have WMA file extensions. Older media files, video or audio,
may have the ASF extension, but this is only of historical interest.
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The
ASX
element defines the enclosed script as being part of a Windows Media
metafile.
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The
Entry
element specifies the digital media.
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The
Ref href
element specifies the URL of the media.
MMS is the Windows Media streaming protocol that is recognized by
Windows Media Services.
Once this text file has
been created, save it with the file extension WVX (for example,
"myfile.wvx" (an audio redirector file should be saved with the extension WAX).
Import it into your web and then link to it, using the http protocol.
For example:
http://myfile.wvx
The file extension wvx (or
wax, or asx) is
associated with the Windows media player. If your user has the
Windows media player installed (version 7 or above) it will be invoked and
the video will stream from the streaming server.
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Metafile Extension |
When to
use |
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.wax |
All digital
media is audio-only, with .wma file name extensions. |
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.wvx |
Media
contains video, with a .wmv file name extension. |
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.asx |
Media is
created with previous versions of Windows Media Technologies and has
an .asf file name extension. |
Of course there are many features which could
be added to a Windows media metafile. For complete information on
how to create a Windows media redirector files, and most other aspects of
using Windows streaming media, visit the
MSDN web site.
A
Real Media Metafile
A similar process is used to link to a Real
media file. Use a plain text editor, such as Microsoft Notepad, and
create a simple script which contains a link to the Real media file on a
Real server, using the Real Time Streaming Protocol. Then save the
file with a .RAM extension and import it into your web. Finally,
link to the RAM file via and http link. Here is an example of the
simplest possible:
rtsp://real.palomar.edu/palomar/palpromohigh.rm
This simple one line file
contains the following elements:
Internet Protocol:
rtsp://
Real Server Name:
real.palomar.edu
Path to media file: /palomar/
Name of encoded file:
palpromohigh.rm
Assuming you have saved this file with the
filename "palpromohigh.ram," (it is always a good idea to name your ram
files with the same name as the media file to which it links, though this
is not required), construct your web page link to this file like this:
http://palpromohigh.ram
(Go ahead and click it. It really
works.)
As with the Microsoft
redirector files, there are many parameters and scripting features that
can be implemented through the RAM file. To find out more, visit the
Real Networks production web site:
http://www.realnetworks.com
The Ramgen Alternative
Real provides an
alternative that makes it far easier to create a link directly to your
folder in the following fashion:
http://real.palomar.edu:8080/ramgen/path/yourfile.rm
If you use this style link
on your web page, the necessary RAM file will automatically be generated
and executed by the Real server. Once it is executed, the Real
player will be invoked and your file will play.
Here is one that actually
works:
http://real.palomar.edu:8080/ramgen/palomar/palpromohigh.rm
This IS the actual link within a web page.
It is not contained within a separate redirector file.
What if the user does
not have the Windows or Real media players?
Links to the stand-alone
media player, while simple, only work if the user already has the player
installed. Therefore, it is customary and courteous to supply a link
to a web page where the user can download the appropriate player if
necessary. Here is a typical example, showing links to low and high
bandwidth targerts, and helpful links for obtaining the players:
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Detailed Example:
Click here for screen shots and
explanations on how to
create a Real media redirector file using
Microsoft Notepad, and then how to upload the file to your web site and
link to the file using Microsoft FrontPage. |
Embedding Media Players
on a Web Site
If you are familiar with entering raw HTML
code into a web page, and know a little about scripting,
you may want to embed an instance of the media player
on your web page. This is more of an
advanced application, however, and you may not
want to undertake the coding.
If so, call Academic Technology (ext.
2877) for assistance. We will be glad to
help you.
Since this can be a complex process, the
exact methods are not described here. Rather, a couple of examples
are shown, and links to the technical documentation at the Microsoft and
Real support web sites are provided.
Note that the Real Producer Basic (free software) will produce a web page for you
with the Real player embedded.
Additional Document Resources
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