A webinar is a live online event in which one or a small number of presenters broadcast to a potentially large audience — commonly dozens to thousands of attendees — who participate mainly through text chat, polls, or a moderated Q&A rather than by sharing their own audio or video. This one-to-many broadcast topology is the core technical difference from a virtual classroom, where all participants are expected to speak and show video. Webinar platforms optimise for low-latency streaming to many simultaneous viewers rather than the bidirectional, low-latency full-duplex media exchange that characterises a video call. In learning contexts, webinars are used for large-group instruction, product demos, and thought-leadership sessions; they are not well suited for small-group collaboration, skills practice, or interactive exercises that require each learner to actively produce rather than passively receive. The recording of a webinar is usually the most valuable long-term artefact: a one-hour live event reaches perhaps a few hundred attendees, but a well-chaptered, captioned recording published to an LMS or public portal can be viewed thousands of times. For engineers, the key distinction is infrastructure: a webinar back-end scales by adding CDN capacity, while a virtual classroom back-end scales by adding SFU (Selective Forwarding Unit) media server capacity — the two architectures are largely separate. A common product mistake is choosing webinar infrastructure and then trying to add collaborative features — breakout rooms, shared whiteboard, per-learner video — which require a different media topology. Understanding whether a client wants a webinar or a virtual classroom is therefore a critical scoping question, not an aesthetic one.
The handbook · 7 volumes
Fora Soft Video Engineering Handbook
A webinar is one host speaking to many viewers, which lets you trade interactivity for scale with live streaming instead of a full video call. Our seven volumes cover the video stack; for webinars start with Volume 3 on WebRTC, CDNs, and the economics of delivery, then Volume 2 on ingest and HLS, with voice processing in Volume 4. Written by Nikolay Sapunov, CEO at Fora Soft.
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