An ad break (also called an avail, short for availability) is a slot in the content timeline reserved for advertising. In live and linear it is signaled in real time by SCTE-35 markers; in VOD it can be pre-defined at known points. The break has a duration that the ad system fills, often with a pod of multiple ads.
Breaks are where content and monetization meet, and their handling is full of edge cases: aligning the break to segment and keyframe boundaries for seamless insertion, deciding what to do if no ad fills the avail, and ensuring the content resumes cleanly afterward. Accurate avail signaling is the prerequisite for both SSAI and CSAI to monetize without disrupting playback.
The handbook · 7 volumes
Fora Soft Video Engineering Handbook
An ad break only works if the cue reaches the packager and player at the right frame, otherwise ads cut into content or never show. Our seven volumes cover the whole video stack; for ad breaks start with Volume 2 on HLS, MPEG-DASH, and CMAF packaging, then Volume 3 on players and Volume 1 on encoding at splice points. Written by Nikolay Sapunov, CEO at Fora Soft.
Ad breaks firing late or cutting into your content?
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