Videoconference or Webcast, what is the difference?

I get enquiries regarding VC (Videoconferencing) and Webcasting from all points of the technical spectrum, from experienced production managers to event organisers who are trying to fulfil a vaguely-worded last-minute request from their client.

This means that often the terminology can get confused when people start asking for one type of service, but are actually referring to another. So, in order to demystify the matter, here is a quick overview:

VC vs. Webcast, the core differences.

A webcast is fundamentally a one-to-many style of transmission. I.E. there is one source of origin (your live event) and many recipients (the online audience), and unless organised through what would be referred to as a “side channel” e.g. email, twitter, facebook integration, there is no provision for a return communication path from the online audience to the live event. Of course it is possible to set up these “side channels” to facilitate Q&A and feedback, but in some cases they would be disruptive to the live event.

Not only that, but the fundamental nature of a webcast does not lend itself to two-way communication, due to the delays involved in compressing and distributing the video stream around the globe. these delays can be 30-40 seconds or higher depending on factors on the receiving end of the stream.

Enter VC.

Two-way communication is best left to the specialist low-latency technology that is videoconferencing.

Videoconferencing is best described as a one-to-one or few-to-few style of transmission. One advantage to videoconferencing is that it is a low-latency form of transmission. As there are fewer recipients of the video stream there is no need for the extensive data distribution and caching involved in webcasting. This facilitates flowing two-way discourse over the VC link as if the participants were in the same room.

Another advantage to VC is that auxilliary information can be transmitted bidirectionally across the VC link as a distinct video channel, such as a live powerpoint or keynote presentation.

The simplest type of application for videoconferencing is for it to be used exactly as you would a video-telephone, but this doesn’t really do full justice to what can be achieved with videoconferencing.

For more advanced VC applications, potentially dozens of VC participants can be joined together into a “virtual meeting room” using a centralised bridging service to bring them all together. this kind of videoconference call facilitates boardroom-style meetings spread over vast geographical distances, but with all participants interacting as if they were in the same physical room.

Mixing the two technologies.

So you see, it would be impractical to broadcast a live event to thousands of online viewers using videoconferencing, nor could you hold a fluid two-way conversation between a live presenter and a web audience using webcasting technology alone.

However, it is not uncommon for webcasting and videoconferencing to be used to great effect at the same event. For example, if a keynote speaker was unable to physically travel to the meeting location but was still keen to speak to your audience, you could bring in their video, audio and presentation content to the physical conference room using a VC link. This could then be shown to the live audience in real time, facilitating fluid Q&A between the meeting room and the remote speaker.

Using a combination of microphones and cameras in the meeting room and the video and audio from the VC link, the whole combined meeting could then be webcast to an online audience. This online audience would then be able to utilise the pre-organised “side channels” that we talked about earlier, to facilitate Q&A with the live audience and with the remote speaker via VC, by virtue of a chairperson fielding questions.

Bringing it all together.

So in summary, both webcasting and videoconferencing have their strengths, but neither can fulfil the role of the other. For communicating at scale to a large audience; Webcast is what you want. If fluent two-way communication is what you’re after; VC is the way to go.



Before you ask… While it may be technically possible to combine a large audience with the ability for unmoderated, unstructured two-way communication, in reality this isn’t usually a good idea. Using the quality of communication exemplified by politicians in the house of commons as an example, you can imagine why a one-way flow of information can sometimes be constructive.