The CTV supply chain runs in real time, completing a full auction and ad delivery in under 200 milliseconds. Here is what happens when a viewer presses play:
- Ad break approaches: The publisher's ad server detects that an ad slot is coming — a pre-roll before content starts, or a mid-roll break in a live stream. It prepares a bid request describing the available impression: device type (CTV), content context (live sport, VOD), location, floor price, and any audience signals.
- SSP runs the auction: The bid request goes to the publisher's supply-side platform (SSP), which broadcasts it to connected demand-side platforms (DSPs). Each DSP evaluates whether any active campaign matches and submits a bid. The SSP picks the highest bid above the floor price. For premium India CTV inventory (JioCinema, Hotstar IPL), much of this is not open auction — it is private marketplace (PMP) deals with pre-approved buyers at negotiated prices.
- Ad is delivered: The winning DSP's creative is retrieved and delivered to the viewer. JioCinema and Hotstar use server-side ad insertion (SSAI) — the ad is stitched into the video stream at the server before it reaches the viewer's device. The viewer sees a seamless stream with no buffering between content and ad.
- Impression is recorded: The ad server fires VAST tracking pixels at key events: impression start, 25%, 50%, 75%, and 100% completion. Both the DSP and the publisher log the impression. In India, discrepancies of 5–15% between DSP-counted and platform-counted impressions are common and normal — reconciling the two counts is standard campaign management.
The key India-specific point: because JioCinema and Hotstar use SSAI, third-party ad verification vendors cannot fire tracking pixels from the viewer's device directly. Measurement relies on platform-reported data or SSAI-compatible measurement integrations that the publisher must explicitly support.
Full guide
For a complete explanation, read: The CTV supply chain explained: from content owner to advertiser impression