What is live webcasting and how does it work?

Live webcasting is what many people first think of when streaming media is mentioned— because they have heard about live rock concerts being broadcast on the internet, or phone in shows where some celebrity or politician takes a few live calls while broadcasting an interview over the web.

Live webcasting is what many people first think of when streaming media is mentioned— because they have heard about live rock concerts being broadcast on the internet, or phone in shows where some celebrity or politician takes a few live calls while broadcasting an interview over the web.

Webcasting has a certain amount of appeal, because it promises to give almost anyone the ability to broadcast their concert, annual meeting, conference keynote speaker, or golf tournament award ceremony to virtually the entire world.

From a technical point of view setting up a webcast is more complicated and somewhat more risky than creating a library of archived files. Because it is a live event, it involves all the usual risks associated with live events. Things usually don't go quite as planned; equipment breaks down; cables are forgotten back at the studio; lights burn out, people say stupid things or start drooling, and so on.

The second complication has more to do with the specific technology used in webcasting. Since you have to "encode" a media stream before sending it out over the net, the encoder has to work more or less in real time. The cameras and audio equipment feed the signal into the encoding device. Then the encoding device compresses and formats the data so it can be sent along to the media server — presumably at a different location — where it is then streamed at the correct bitrate and ultimately played by the correct sort of media players at the other end.

At first blush, this process may seem too fraught with variables to actually be counted on. But in practice, if the production company — the guys running the cameras and creating the final mix — if they can keep the signal running, then in fact it is quite a reliable method of broadcasting.

The weakest link in the production chain is the connection between the encoder onsite at the live location — and the server — presumably somewhere out there in cyberland. But in many cases a simple DSL or Cable connection is perfectly satisfactory, since the encoded signal you are transferring is usually no more than 300-400 kbps.

Complications certainly arise when deciding what format and what bitrate to use for your live webcast. Archived streaming media is often encoded in different formats and at different bitrates, but this is often not possible with live webcasts. In many cases the webcaster just has to pick the format he considers the most likely to be used by the largest number of viewers, and go with it.

In real life situations restricting available formats like this is not as difficult as it may sound. Many webcasts are done for corporate clients and broadcast over restricted corporate networks. The specified format is just part of company policy, based on what the network administrators know is running on corporate desktops.

Other webcasts are subscription-based — things like online training or "learning-at-a-distance" services, or even online rock concerts or movies. Using a specified format and bitrate just becomes part of the requirements to take advantage of the service.

Who can take advantage of live webcasting?

The users of webcasting tend to fall into two or three groups based on content and audience. At the "low" end of the scale are experimental services that have essentially no audience. These are individuals and companies experimenting with the technology hoping to find an idea that will have some audience appeal. At the "high" end of the scale are large broadcast organizations, rebroadcasting their traditional radio or TV signal to potentially very large audiences. Big name concert promoters and movie streamers tend to fall into this second category.

Between these two extremes are events with a narrowly defined audience. Most of them are corporate in nature — conference keynote addresses, the CEO's annual message to the troops, live reporting of quarterly corporate results, etc. Some of these events are akin to videoconferencing where, for instance, a live training session is webcast to a select group of customers or employees, or a lecture is webcast to a specific group of students.1

As time goes by new applications for streaming will be developed. A few months ago I heard of a company setting up cameras in daycare centres and webcasting video of the children so their parents at work could watch their children on their computers.

This idea may or may not ultimately fly; but it suggests a range of possibilities from video surveillance to in-house newscasting, to narrowly focused corporate event coverage, where we are not talking about one-off events like concerts, but rather regular coverage of recurring events in a controlled setting — like in a studio, newsroom, or briefing room. In such a situation the broadcast source would be controlled and predictable, the transmission system properly constructed and tested, and the viewing audience motivated to watch and equipped with the appropriate tools to do so.

The other area that sounds plausible, but as yet has not proven to be economically viable is entertainment-based, or even information-based live programming produced specifically for webcasting. The challenge is to define a potential audience, create streaming programming specifically for that audience, let them know the service exists, and keep them coming back. And of course, find enough advertisers to support the service.