Basically, a WebCast is a media presentation often created by multiple cameras ingested into a streaming device like a TriCaster or LiveStream Flypack and distributed much like a TV show over the Internet using streaming media technology. This individual content can be distributed worldwide to many simultaneous listeners/viewers.
For all practical purposes, a Live Streaming Video Production is the same thing.
Professional live streaming, WebCasting production companies can provide as many as 12 cameras which may record internally in 4K while streaming to the world in 1080p.
The TriCaster (usually limited to 8 cameras) and the advanced flypacks can provide pre-recorded video via built-in DVRs as well as graphics, animations, lower thirds, etc.
Webcasts/Live Streams are not time-sensitive so they can be viewed at any time, day or night as VOD (Video On Demand).
Webcasting provides both video and audio, the transmitted information is a stream of data from a server.
A decoder is a stand-alone player or a plugin that functions as part of a Web browser.
The information stream from the server and the decoder work together to enable a worldwide audience to watch a live WebCast.