The World Wide Web has evolved rapidly. Ten years ago, a few people, headed by Tim Berners-Lee, were taking their first tentative steps with this new media, putting text documents on web servers. Now we can add pictures, sound, animations and video to our web pages, and websites can now even be created in 3D! With the increased richness of media has come an increasingly technical set of commands to control how content is displayed within web pages and a bewildering array of gadgetry invented to assist us in the development of that content.

In a virtual re-enactment of Australia's dispute over the gauge of railway tracks, a number of companies are jockeying for dominance on the Internet, all promoting a variety of file formats which have been developed to display of HTML (not all pages display the same when looked at using Netscape Navigator and Internet Explorer), the transmission of audio and video and so on. These differing formats don't always work with one another, causing a great deal of confusion and frustration amongst web creators and users alike.

The advice given here relates to creating streaming video on a PC but the principles are the same on a Mac. The main difference is that on a Mac users would generally save footage to the computer as Quicktime files rather than AVIs.

There are a number of different file formats which can be used for video on the World Wide Web. Each has particular merits as well as problems. Common formats include the following:

  • Quicktime - designed originally for Macintosh computers but now used on Macs and PCs. This format can be used in most versions of Internet Explorer and Netscape Navigator. Quicktime files are usually quite large, but the new version, Quicktime 3, can stream video across fast connections.
  • AVI - the native format for video on PCs. This format can also display within recent versions of Internet Explorer and Netscape Navigator on Macs and PCs. Video is usually of high quality, but degrades as higher levels of compression are used.
  • MPEG - Medium file size, high quality audio and very good video. This format can be streamed across the web and used in websites but will normally not play within a web page and requires an external player, as well as a relatively fast computer and a good video display card. Earlier formats of MPEG needed special hardware in the computer to be able to play but the newer versions allow for software-driven display of the format.

Streaming Video

Files saved as Quicktimes, AVIs or MPGs are usually are too big for display on web pages if you are planning on making your pages available to users with slow modems, as they are usually measured in MB rather than in K. A better option is to use file formats which give small file sizes and which start playing the minute they begin to download, rather than waiting until the whole file has arrived on your computer. This technique is referred to as Streaming Video. Because the files are smaller they cannot contain as much information, so the image quality is not as good as the larger files, but the image quality has improved dramatically over the last two years as better compression codecs have been developed, and there is no reason not to expect further improvement.

The most commonly used streaming format is probably RealMedia, but there are many others. Video quality varies from good to very poor, degrading rapidly as higher levels of compression are used.


RealMedia files can be run from most standard web servers, though they work better when run through a RealMedia Server. The server software allows several users to display the same file at the same time and can also be used to serve live video to the web, should you wish to do this during a conference or special event. The Victorian Department of Education maintains a RealMedia server on the www2 server and subject Associations are able to place their Real Media files on it. Email Judy Schober (This email address is being protected from spambots. You need JavaScript enabled to view it.), or phone her on 03 96372152 to arrange for your files to be added to the www2 server.

To put video on a web server you first need to obtain or create the digitised footage you wish to use. You will need a way of importing footage from your video camera or VCR to your computer. Usually this is done by "capturing " the video through a card added to your computer, but there are also external devices which can be used to capture video and which connect to either a parallel or USB port. Normally the captured video is stored on PCs as an AVI file. Files should be stored in the highest quality possible, though this takes up a lot of space. A 20 second clip of good quality raw AVI footage can be almost 20 Mb. A good rule of thumb is to allow about 1 Mb per second for video captured to your computer.

Obviously, this can take up a lot of space on your hard drive, so think about using a separate hard drive just for video.

It will probably be necessary to edit the video before you create the RealMedia file. The Non Linear Editing software which comes with your video capture card will allow you to place several pieces of video into one new timeline, with special effects, titles and even extra sound. The finished product can be saved as a new AVI (or Quicktime or MPEG) file, with the dimensions you wish to use on the web. Once you have your file ready you can start the RealProducer software. This is used to convert your AVI file into a RealMedia file. It will also work with audio files if you wish to experiment with this as well.

The RealProducer software can be run using a "wizard " which will guide you though each step of producing the video, or you can work through seach step manually. You can choose to allow users to copy your files to their hard drive or record your content, if you are serving live footage, specify what speed network you want the file to be best suited to, identify whether audio or video is more important, and so on. Once the file has been created you can even use the software to create a web page which incorporates the video and publish the page to the web. The software also offers you the option of emailing the finished clip to other people. This software can be used to produce both video and audio files. Audio is still used more frequently on the web, as the tools required to create high quality streaming audio can be as simple as a tape recorder which can plug into your line in socket on your computer.

The finished RealMedia file can be more than forty times smaller than the original AVI, making it practical to stream the file across the web. The other streaming formats also achieve similar levels of compression.

Unfortunately, as the RealMedia products are constantly being updated, they do not allow the player or encoder to be distributed by third parties, so users must download the creation and player software directly from the RealMedia website. There is a solution to part of this problem though. Microsoft's Windows Media Player does play RealMedia files, along with.3 several other formats, so if you wish to distribute these types of files on CD, the Windows Media Player can be distributed with them. The player is available as a free download for Windows 3.11, 95, 98, NT 4.0, and Macintosh computers.

Streaming video formats are "lossy ", that is a considerable amount of the information contained in the original video is discarded during compression of the file. Instead, much of the information is obtained by looking at the information about neighbouring pixels and interpolating the information for the pixel in question. This can result in much smaller files but can introduce blurring and other "artifacts " which reduce the clarity and sharpness of the finished product. Generally it is best to compress video as little as possible, though different end uses will suggest differing levels of acceptable diminution of quality.

Once you have imported captured your video you will be able to play it and edit on your computer, but it is likely that you would not be able to share the footage with other computers unless they also have a video capture card installed. This is because the video will probably have been captured using the MJPEG codec, and relies on hardware based compression and decompression. The solution to this is to create compressed version of the original file, which will not rely on special hardware in the computer to allow playback. The formats listed below are suitable for this.

The same file, saved in Quicktime, AVI, MPG and RealMedia formats results in considerably differing file sizes. For the web the only real option for users with slow modems would be the RealMedia format, but for Intranets the MPG format might be worth considering, while for CDs, I would suggest using Quicktime or perhaps AVI videos if you want to incorporate the video in web pages suitable for Macs and PCs, or MPGs if you are happy for the video to play in a separate window.

Example file sizes and compression times for a 20 second clip

File Type


Creation time

Uncompressed AVI (needs hardware to play)


downloaded in real time from video camera

Compressed AVI (cinepak codec)


10 minutes

Compressed AVI (MP4 codec)


1 minute



6 minutes

RealMedia (suitable for 56K modem)


40 second

From this table you can also see that processing video on a computer takes quite a lot of time. The figures above were obtained on a PII 400 MHz system with 128 Mb Ram, using a Miro DC10 Video capture card. Different codecs will give different results, and your choice of codec will be determined by the end use intended for your video clip. Using the MP4 codec at its highest quality instead of cinepak, the AVI file would be only 2200K and would take less than a minute to render. The disadvantage of this format is that the image is much.4 more blurry and does not display as well when enlarged. In a manner similar to MPEG video, the resulting file also needs a fast processor and a good video display card to display properly.

Pointers for creating content

Streaming video works best with video clips with fairly small dimensions. The examples above were for clips made at 384 X 288 pixels. Reducing the dimensions to 160 X 120 pixels dropped the conpressed AVI file to 3328K. The RealMedia file was 88K and still played at 7 frames per second. Files with smaller dimensions will work better for users relying on 28.8 or 33.6K modems, but you will reduce the amount of detail possible. Particularly for users with modems, a "talking head " is the best sort of video footage to stream. Because of the small frame rate (somewhere between 1 and 10 per second is usual) it is difficult to adequately display fast moving, action clips. Use closeups of faces, or views where little changes from frame to frame. You should endeavour to always use a tripod or other solid mount. Keep in mind that dark video doesn't display well; use artificial lighting if necessary when shooting your footage. Don't zoom in or out unless it is absolutely necessary - streaming video doesn't cope with the zooming segment very well at all.

Once you have collected your video footage, before you digitise your clips, view it on a television and make some notes about which bits you want to include in your RealMedia clip, and which order you want them in. Creating this sort of log can make it much easier to come back to a project after a few weeks away from it. Next you need to get your footage into your computer. Use an internal Video Capture Card, or an external device such as Iomega's Buzz. Digitize each segment separately and save them as independent AVI files. By saving each piece separately you can choose the order in which you connect them in your final clip. Use a Non Linear Editing program like Adobe Premiere or MediaStudio to join your files into a single timeline and then save the clip as an AVI file, using the Cinepak codec. You will then be able to run the RealProducer and convert the AVI into a RealMedia file.

Having given the above pointers, I should say that a handheld camera with reasonable light and minimal editing is better than nothing at all. Try taking some footage and digitizing it to put on the web. Even without any digital editing you will be surprised how good your files can look. Hopefully, your first efforts will spur you on to bigger and better clips.

More information

There are several sites on the web which give excellent advice on desktop video production and streaming video. Some are updated weekly, while others haven't been updated in over a year. Keep in mind that the technology is changing rapidly, so advice more than a year old is almost certain to be quite inaccurate now. Look for dates on the pages you read to get an idea of the currency of the information. Most of the companies that produce streaming video players also have the tools to make content for their player. These are often available as a free download - part of their strategy for obtaining market share for their player. These sites will often contain tutorials as well. The tutorial sites listed below are the ones I have used in the past and found to be useful. I'm sure that there are many others as well.

Tutorials and product information.


Video for Windows

(.AVI - Audio Visual Interleaved). The most common video format for PCs, it can now also me displayed on Macintosh computers. The file sizes are large, but playback quality can be excellent.


(.MOV, .QT or .MOOV - abbreviation for movie). Originally for Mac Users but now available for Windows, the quicktime format is used primarily for audio and video, but can also carry other time-based information such as laboratory instrumentation data and stock reports. Video is normally excellent, but playback varies on different computers. QuickTime movies created on a Macintosh must be "flattened " or made self-contained, by moving some data from the file's resource fork to the data fork. Movies made on a PC generally will also display on a Macintosh.


(.MPEG, .MPG, .MPE, .MP2, .M1V, or .MPA - developed by and named for the Moving Picture Expert Group). This format works on most platforms and gives high quality results, but requires a powerful processor. MPEG is fast becoming the standard for video and CD ROMs. DVD and High Definition television will also use an MPEG variant to store and transmit enormous amounts of information rapidly.


A software system for compressing and decompressing images and videos. Some common codecs for video include Cinepak, Intel Indeo, and MP4.

Non Linear Editing.

By collecting several small video clips on your computer you can assemble them into a larger clip, in whatever order you choose, using transitional effects between clips, adding music and voiceovers. Editing digitally also helps keep the quality of the finished product as high as possible.

Streaming Video.

Video which starts to play on your computer the instant you start downloading it, rather than waiting until the entire file has arrived.