Basic concept and function
- Server-side ad insertion (SSAI) integrates ads into the video stream on the server before reaching the user.
- Ads and content are stitched into a single stream, avoiding separate calls from the user’s device.
- It delivers a seamless, buffer-free ad experience that feels like part of the content.
- The viewer cannot easily distinguish between the ad and the main video stream.
- SSAI is often referred to as “ad stitching” in OTT and live streaming environments.
Benefits for user experience
- Reduces buffering or delays when transitioning between ads and content.
- Prevents ad blockers from detecting and removing ad segments.
- Provides smoother playback across multiple devices and platforms.
- Ensures high-quality ad delivery even on low-bandwidth connections.
- Enables consistent ad insertion for live streams and on-demand content.
Benefits for advertisers and platforms
- Increases ad viewability rates by minimizing skips and ad-blocking.
- Allows for precise audience targeting with dynamic ad replacement.
- Tracks performance metrics like impressions and completion rates.
- Helps platforms maximize ad revenue through personalized ad delivery.
- Ensures compliance with brand safety and geographic restrictions.
Technical implementation process
- A video manifest is created where ads are inserted at predefined cue points.
- Ad servers deliver the ad creatives which are transcoded to match content quality.
- Content and ads are packaged together using streaming protocols like HLS or MPEG-DASH.
- CDN networks then distribute the stitched stream to the end user.
- SSAI frameworks often integrate with DRM and analytics tools.
Comparison with client-side ad insertion
- In client-side ad insertion (CSAI), ads are fetched separately by the user’s device.
- SSAI offers better playback continuity and is harder for users to skip.
- CSAI provides more interactivity but is prone to ad blockers and latency.
- SSAI is preferred for smart TVs and low-power devices due to stream stability.
OTT platforms may use both techniques based on content type and audience behavior.