How SSAI works
Markers in the content show where ad breaks fall. When a viewer reaches a break, the stitching service asks an ad server which ads to show that viewer, then rewrites the stream's manifest so that ad segments replace or follow the content segments. The ads are encoded to match the program's quality levels.
Each viewer gets their own manifest, so two people watching the same stream can see different ads.
SSAI vs CSAI
With client-side ad insertion (CSAI), the player itself pauses the content, requests an ad and plays it in a separate ad player. It is simpler and supports interactive ads and detailed measurement, but ad blockers can stop the request, and the switch between players can cause a visible pause.
With SSAI the ad is part of the stream. Playback is seamless, ad blockers have little to act on, and it works on devices with limited players, such as older smart TVs. Measurement and interactivity are harder, because the player is not aware it is showing an ad unless extra signalling is added.
When SSAI is the better choice
- Live streams and linear channels, where breaks must start and end exactly on time
- Television apps, where viewers expect a broadcast-like experience
- Services with a significant share of ad-blocking viewers on the web
- A wide range of devices that would each need a client-side ad integration
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