Whole-Ad Product Swap: Deterministic Planning First, Model Only Where Forced
Variant Multiplier already let an editor swap one section of a winning ad and keep the rest. The next request from a real production job — replacing product SL-603 with SL-808, a different hearing-aid SKU, across an entire finished ad — was a different shape of problem. It's not "change one section," it's "change every mention of the product, everywhere it appears, while keeping literally…
The Variant Multiplier tool allowed an editor to swap one section of a winning ad while keeping the rest intact. However, a new request for replacing a product SKU across an entire finished ad required changing every mention of the product. The editor expressed concerns about word-by-word changes rigidly affecting other elements like music and voice quality.
To address this, the team first improved the transcript editor, enabling users to select and edit by sentence or scene instead of just words, and allowing them to copy and paste lines verbatim. Next, they created a product catalog, providing a single source of truth for product identity. The core of the solution is a deterministic planning process, where the engineer decides to swap products only if a clear rule exists, otherwise, they rely on a model.
This approach prevents accidental changes to music, pacing, or voice quality. For the audio side, a separate render called Audio-only render was developed, which reissues the ad with new audio while keeping the video stream unchanged. Captions were also addressed, regenerating them from the swapped audio to ensure accuracy. The final verification step compared the new tool's caption approach against the in-house reference implementation, confirming its correctness.
Written by urgent.news from Dev.to's reporting — not their text. Machine-written — may contain errors; check the original before relying on it.
