MWS Newsletter: Volume 3, Issue 5

Digital Video, Part II: Streaming Media

In this third and final part of my series of newsletters about Web video, I'm going to talk about streaming. If you missed the first 2 parts, or if you want to review, you can read them here.

Streaming refers to the method of delivering media (audio and/or video) to the consumer of the media as it is being consumed (listened to or viewed). Examples of media that are inherently streaming include television and radio. Examples of media that are inherently non-streaming include CDs and books.

There are two basic ways that media is streamed over the Web:

1. using a streaming server. A streaming server is software on the server that sends data to the browser or to a media player to be displayed as it arrives. Streaming servers can negotiate with the viewer's computer to determine the best speed to feed data, can be used to stream live events, and are capable of managing large amounts of traffic.

2. progressive download. Progressive download, or HTTP Streaming, works by sending just enough data to the viewer so that the video can start playing before it's completely downloaded. The idea is that the download just needs to stay one step ahead of the viewer. Progressive download is much less expensive than using a streaming server, but it's also much less reliable.

The key to both types of streaming video is to have enough bandwidth for the number of simultaneous viewers you expect. The math for calculating the bandwidth required is simple: you just multiply the bit rate of the video by the number of visitors you expect.

A typical 'high bandwidth' version of a video might be compressed to a bit rate of 300 kbps 1. If you expect to have 100 simultaneous viewers, the amount of bandwidth you'll require for streaming the video is 300 * 100, or 30,000 kbps (30 Mbps). If you expect to have 1000 simultaneous viewers, you'll need 300 Mbps of bandwidth...which is some pretty serious bandwidth.

Audio is much easier. FM radio quality audio has a bitrate of 96kbps. A typical bit rate used by streaming media services is 128 kbps. At that rate 234 listeners can be served using the same bandwidth as is needed to serve 100 video watchers.

Chris's Brilliant Tip(tm) for this Issue (if you made it this far, you deserve it): Offer an audio-only option when possible. Video is cool, but if it's just a video of a talking head (and 90% of them are), some of your visitors may prefer to just listen. Giving them that option makes your site more usable, reduces your bandwidth requirement, and can save you money!

Next month, I'll finally get to the long-awaited "Understanding Web Site Stats" issue of the MWS newsletter.

In the meantime:

For more information about how Minnick Web Services can help you achieve your goals, please visit our web site, www.minnickweb.com or contact us.

To find out more about our digital proofing, publishing, and reporting technologies, visit the eBookHost demo at demo.ebookhost.com.

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Chris Minnick

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