Glass-to-glass latency is the end-to-end delay across the whole live chain: capture, contribution, ingest, transcoding, packaging, CDN delivery, and finally the player's buffer. Every stage adds a little, but the player buffer and segment duration usually dominate. It is the number that matters when a viewer hears the neighbours cheer a goal seconds before their own stream shows it.
Standard HLS/DASH runs around 20-30 seconds; low-latency modes (LL-HLS, LL-DASH) bring it to a few seconds; WebRTC reaches sub-second for truly interactive use. Cutting latency means shrinking buffers, which trades directly against resilience to network jitter - the central tension of live engineering.
The handbook · 7 volumes
Fora Soft Video Engineering Handbook
Glass-to-glass latency adds up across capture, ingest, transcoding, packaging, CDN, and the player buffer, and segment duration usually dominates it. The seven volumes cover the video stack; for latency start with Volume 2 on the glass-to-glass budget, ingest, and LL-HLS packaging, then Volume 1 on encoder delay, with player buffers in Volume 3. Written by Nikolay Sapunov, CEO at Fora Soft.
Live streams arriving 30 seconds behind the action and spoilers reaching viewers first?
We will measure your live chain stage by stage and send a latency budget with the changes that get you to your target. 250+ video products shipped since 2005.
