A segment is a short, independently downloadable piece of the video timeline - typically 2-6 seconds - and the fundamental unit of HTTP adaptive streaming. The player reads the manifest, then fetches segments one after another, deciding at each boundary which rendition's segment to pull.
Segment duration is a core tuning knob. Shorter segments lower latency and make switching more responsive but increase request overhead and can hurt cache and compression efficiency; longer segments do the reverse. Because segments are plain HTTP objects, they cache beautifully in any CDN, which is what makes internet-scale delivery cheap.
The handbook · 7 volumes
Fora Soft Video Engineering Handbook
Segment duration sets the floor for live latency, the granularity of ABR switches, and the number of requests your CDN serves. We wrote seven volumes covering the video stack; for segments start with Volume 2 on segmenting, HLS, DASH, and CMAF, then Volume 1 on GOP and keyframe alignment, with ABR in Volume 3. Written by Nikolay Sapunov, CEO at Fora Soft.
Choosing segment duration for low latency without overloading your CDN?
We will review your packaging and latency goals and send segment settings with the tradeoffs for latency and cost. 250+ video products shipped since 2005.
