CampaignReel

Ad placement specs against what generators output

What each ad slot demands before a generator is chosen

A placement sheet collects what one platform publishes about the ads it will accept, then sets those numbers against what generators actually emit. Collisions are the point of the sheet. As of 2026-09-12.

Where a placement spec and a generation limit collideA placement publishes a ceiling and often a skip threshold. A generator publishes a maximum clip length. When the ceiling exceeds the clip length the ad cannot be made in one pass, and the production becomes an edit with continuity requirements that nobody budgeted for.Does one generation fill the slotYesGenerate itOne pass, one look, no continuity problem to solve.NoAssemble itCuts, matching and a tool chosen for continuity ratherthan for quality.Decided by two published numbers
Fig. 1 The collision is arithmetic and can be spotted at the brief. It is usually spotted at the edit instead.

Length is where most of the collisions happen. Platforms publish hard ceilings and skip thresholds; generators publish maximum clip durations. When a ceiling is longer than a single generation, the ad has to be assembled rather than generated, and the team finds out at the edit rather than at the brief.

Aspect ratio is the second collision and the quieter one. A placement that takes only one ratio, and a tool that emits a different one by default, produces a re-render or a crop that costs the composition.

Each sheet names the help-centre page every number came from, because platform specs change without announcement and a figure with no address behind it cannot be re-checked six months later.

1The placements

  • YouTube — The lengths Google states for bumper, non-skippable, skippable, in-feed, Shorts and Masthead ads, and what counts as a paid view on each.
  • Bumper ads — The length Google states for bumper ads, and how many generations each tool's own published duration limits imply for one of them.
  • Non-skippable in-stream ads — The length Google states for non-skippable in-stream ads, and how many generations each tool's own published duration limits imply for one of them.

A placement earns a sheet when the platform publishes its limits in a page a buyer can open without an ad account.

Elsewhere in the kit: Tools, Axes, Pairs, Questions, Terms, Learn, Data. How a spec gets onto a sheet is set out on the method page.

2A generator's ad pipeline

For ad work around “Placements”, SceneMixer's pages explain how its ad projects are produced:

16:9 landscape (SceneMixer's default) and 9:16 vertical (the usual short-drama frame), chosen per project.

SceneMixer, Seedance 2.0 in a Real Short-Drama Pipeline — “Which aspect ratios does the pipeline generate?” (read 2026-10-13)

The layout follows the project's aspect ratio, which is set when the project starts.

SceneMixer, How the Episode Editor Lays Out Vertical (9:16) and Landscape (16:9) Projects — “Can I switch between the two layouts?” (read 2026-10-13)