Video on the Web - Part 1

by Michael Mattox of
Advanced Web Video

As the web continues to grow at an incredible rate, technology continues to grow with it. It was over a year ago Progressive Networks introduced "Real Audio", a method of streaming audio over the Internet. Streaming is the ability to start processing data, before all of it has arrived. A 30 minute audio recording can take up several megs, and no one wants to wait 20 minutes to hear an audio clip. So streaming audio was invented. The same concepts apply to video, and a little more than one year later streaming video arrived. Since video files (with audio) are much bigger than audio files alone, streaming video proved to be more difficult, but at the same time just as necessary.

Digital video files require any where from 90k to 1 meg per second, depending on compression. The higher the quality, the larger the file size. Full screen, full motion (30 fps - frames per second) VHS quality is achievable, but too large to transmit over the Internet. Sending video over the Internet and telephone lines required two things: A very high compression rate to reduce the file size and special software to support streaming. The high compression rate is achieved by storing the differences between frames instead of the entire frame itself. "Headshots" (videos of a persons upper body, like a newscaster) compress very well and yield high frame rates (around 10 fps) because the movement is restricted to the subject's face. On the other hand, "action scenes" such as movie trailers do not compress well because the difference between frames can often be 100%. Action scenes tend to yield the minimum frame rate of 1 fps. Most users prefer even just 1 fps over no video at all because it gives them something to look at while listening to the audio track.

The most common regular (non-streaming) video formats are AVI for Windows, Quicktime MOV for Mac (and Windows too), and MPEG for all platforms, including UNIX. These formats are designed for optimal quality, and are not suited for streaming. Currently there are two formats that are specifically designed for streaming video over the Internet over low bandwidth (modems): VIVOActive and VDOLive.

VDOLive seems to be the most popular, so I will mention it first. VDOLive uses special server software that is run on the web server, and special player software that is run on the user's computer. The server software will adjust the stream according to the available bandwidth. A user with a 14.4k modem will see video that is optimized for his connection, while a user with a direct connection to the Internet would see video with higher quality. Several large companies, including CBS News, PBS, and CBC are using the VDOLive format. VDOLive sounds great, but there is one major disadvantage to this format: While the player is free the server software is extremely expensive. It is priced according to how many "streams" (simultaneous users viewing video) you require. The entry price is 5 streams for $1,200. This is way out of reach for most website owners. Larger websites would require additional streams, which range from $2,000 for 10 streams to $12,000 for 100 streams.

While VDOLive is geared for large corporations (who can afford the high priced server), VIVOActive is more suited for the smaller website. VIVOActive does not require any special server software. In fact, it uses a standard MIME type, like graphic images such as GIF or JPEG. It is up to the player to process the video stream and display it on the user's screen. The advantage of this method is that it is compatible with all existing websites. The only thing the webmaster needs to do is add a MIME type, which takes just a few seconds. This makes it available to users with web accounts through a web provider. The only disadvantage is the server cannot adjust the video quality to the available bandwidth, so the target bandwidth must be chosen when the video file is compressed. Since most users connect to the Internet with a 14.4k or 28.8k modem, a 14.4k bitrate is usually chosen. This lowers the quality for 28.8k users as well as users with a direct connection to the Internet. To work around this it is possible to compress the video for a 28.8k connection. The 14.4k users will see pauses during the video, but once it has been viewed (downloaded), it can be replayed at 28.8k since it will be on the user's machine. Some developers are even providing different links for different users - a link for 14.4k, 28.8k, and higher. This ensures each user gets the best quality, but requires some more work in producing the video files. Like VDOLive, the player is free. A beta version of the producer (needed to convert the video files into VIVOActive format) is currently available for download from the VIVO website. The price of the Producer will be $500.

Now that you are familiar with the two most popular methods of streaming video you can download the players and see the video for yourself. Both are available for Windows and Mac, with Netscape or Explorer.

VIVO Software Inc. http://www.vivo.com
VDOnet Corp. http://www.vdo.net

In Part 2 of this article I will discuss the benefits of video on the web, how you can use it to increase your business, and some of the limitations it has.

About the Author
Michael Mattox is a Webmaster at Advanced Web. He recently started Advanced Web Video, a divison of Advanced Web. He has a BS in Computer Science from Arizona State University, with experience in C++, OOD, and all areas of web development. You can reach him at mattox@advweb.com.

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