What is a video CDN?
A video CDN is a network of edge servers that cache your video segments close to viewers, so playback starts fast and doesn't hammer your origin. When someone hits play, segments are served from a nearby point of presence instead of crossing the internet to wherever the file is stored.
Why video needs one
Video is bandwidth-heavy and latency-sensitive. Serving every segment from one origin means distant viewers wait on a long round trip and your origin pays egress for every byte. A CDN caches segments at the edge, so the first viewer in a region warms the cache and everyone after them is served locally.
Origin vs edge
Your origin stores the master copy; the CDN's edge nodes hold hot copies. The classic failure mode is a fast player with a far-away origin — a cache miss forces an edge to pull a segment across the world, which shows up as a cold-start stall on first play.
What it costs
CDN delivery — egress — is usually the dominant line item in a video bill, ahead of storage or encoding. It's typically metered per GB delivered, which is why per-GB pricing tracks what you actually serve rather than how long the video runs.
How rehelios handles it
rehelios delivers every segment from a global CDN with long cache TTLs, billed per GB delivered — so viewers get a nearby edge and your cost tracks real delivery, not runtime.