Webcasting is the term applied for using the internet to broadcast audio or video transmissions. This is similar to watching events or programmes on television or listening to radio broadcasts. Typically, a single content file can be reached to multiple simultaneous listeners or viewers. The distribution may be done either live or on demand. A computer network is used for this purpose. The process usually also involves the use of a webcam.
Many vendors give webcast solutions, employing various types of technology. Webcasting can be continuous (like a radio broadcast) or episodic (sporadic). It may be permanent (stored) or temporal (ephemeral).It is different from standard content available on the World Wide Web as it provides a constant information stream. Communication between the broadcaster and the listener or viewer can be flexible as it can be provided on-demand or live.
The process of providing webcast support involves capturing, encoding, hosting and delivering events on multimedia and can be used for delivering training, meetings, conferences, infomercials, concerts, distance education lectures (e-learning), advertisements, product demonstrations, technical presentations, question and answer sessions presented by experts or news.
Webcasts are very similar to attending online seminars also known as webinars or online events. Like webcast solutions, webinar services which include recording webinars require webinar software. There are many webinar providers who provide webinar support. In the case of webcast, anyone can register and participate in these virtual events. The broadcast may be presented either as streaming media or as a downloadable file. They are suitable for virtual events and video webcasts.
In Webcasting, technology may be used to send data to a web user, without the user requesting for it. This is referred to as “push” technology, and is in contrast to “pull” technology, where a browser must request for a web page if the user wishes to view it. Broadcasting works on push technology as information is sent even if there is no one tuning in. E-mail is perhaps one of the oldest examples of push technology over internet, as e-mails are received when the sender pushes them to the receiver. The receiver will per force receive the e-mail whether he wants to or not.
Video Webcasts are usually non-interactive. In this sense, webcasting is different from web conferencing, where many-to-many interaction is possible. Specific webcasting licenses or rights have to be obtained from the appropriate bodies before carrying out internet broadcasting of material that is copyrighted. Webcast recording is also possible.
Existing TV and radio stations are usually the largest webcasters. In this case, output is usually simulcast – which is a short form of "simultaneous broadcast". This happens when events or programmes are broadcast over many media at the same time, or having more than one service using the same medium at the same time.