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Creating Streaming Media
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.
In broad outline, there are the four basic steps:

1. Create your digital media.
2. Encode your media for a streaming server.
3. Mount the media on a streaming server.
4. Link to the media from a web page.

The following provides details, but is by no means an exhaustive discussion. It assumes the PC platform and the Windows operating system.

Create Your Digital Media

Analog vs. Digital
Create the media you want to place on the web. This means that you must either:

1. 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.
   
   
2. 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 an average 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.

Encode Your Media For a Streaming Server

Compress Files for the Web
Once you have a finished, uncompressed digital master file - an AVI format video file (which, in fact contains both video and audio tracks, in most cases), 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 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. CCCSAT uses a Microsoft media server and supports the Windows Media Player (.wmv) file format.

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.

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.
Once encoded, your original raw AVI file will become a WMV (video) file. 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.

Mount the Media on a Streaming Server

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. The process of mounting your file is simple, and it is the same for both. First, if you haven't already done so, use our streaming services request form to request an account(s) on one or both of our servers. Details of how to access your folder and ftp your encoded media files to your personal folder will be emailed to you. Once you have moved your encoded file to the streaming server, you are ready to create a link to it on a web page.

Link to the media from a web page

Invoking or Embedding the Media Player
There are two ways to link to an encoded media file on a Windows media server:

1. 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.
   
   
2. 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 the first choice supports accessibility more, it will be the sole focus here.

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), or ASF (older video or audio formats) file. It is a simple text file containing XML commands that control the playing of the media.

Linking to a Windows Media Metafile (invoking the stand alone player)
To link to a Windows media file, you must create a redirector file to the media. A WVX 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://cccsatvideo.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 "cccsatvideo.palomar.edu," in the path (assigned when you request it from CCCSAT), named MyFile.wmv. The wmv extension means it is a Windows Media Video file. Older media files may have the ASF extension, but this is only of historical interest.

1. The ASX element defines the enclosed script as being part of a Windows
   Media metafile.
   
   
2. The Entry element specifies the digital media.
   
   
3. 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"). Import it into your web and then link to it, using the http protocol. For example:

http://cccsatvideo.palomar.edu/YOUR PATH/myfile.wvx

The file extension wvx (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.

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.

What if the user does not have the Windows 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: