Which direction a file limit points
File figures on a specification page usually govern inputs: a reference image, a conditioning video, an audio track. A platform's file rule governs the finished ad. The two live in the same column and answer opposite questions. As of 2026-09-12.
| Kind of figure | Governs | Answers a delivery check |
|---|---|---|
| An input ceiling | What is sent to the model | No |
| An upload cap on a surface | The finished ad | Yes |
| A retention window | How long the output stays fetchable | No, but it sets a deadline |
| An output file size | The delivered file | Yes, where anyone publishes one |
Inclusion rule. Kinds of file statement a specification page can carry. A storage quota for a whole account is a different subject and is not listed. Order. Most commonly published kind first.
1Reading the direction wrong is expensive late
An input ceiling of two hundred megabytes looks like plenty of room and describes nothing a platform will check. A surface capping an upload at a few hundred megabytes is checking the finished file, and no input figure predicts it.
The failure appears on upload day, after the creative is approved internally. That is the worst moment to discover a figure, and it is a figure that was never on the pages the plan was built from.
2Input ceilings still matter, for a different reason
They decide whether a reference image or a conditioning clip can be used at all. On serial work that is the mechanism holding a cast's appearance together, so an input ceiling is a constraint on continuity rather than on delivery.
They also vary by route on some pages: the same file may be accepted one way and refused another. Where that is true the route is part of the specification and belongs in the pipeline design rather than in a footnote.
3The output column is usually empty on both sides
Generators rarely publish the size of the file they return. Surfaces publish the cap but not what a typical file weighs. So the one comparison a delivery check wants is missing at both ends.
The only way to close it is to measure the delivered file, at the tier and length actually used. That is a step in a checklist rather than a row in a table, which is why this site keeps a checklist as well as a register.
A craft note, not a spec. Nothing here is taken from a platform or a vendor, and nothing here should be quoted as a requirement. The sourced material is on published limits. Related: Retention clocks, What a default commits to.
4From brief to placement
For ad work around “Inputs and outputs”, SceneMixer's pages explain how its ad projects are produced:
You can recomposite with different end-card text, and in step-by-step mode you can reshoot individual segments. The finished file can also be downloaded and shared with a link.
SceneMixer, How to Make an Ad from One Photo — “Can I change the ad after it is finished?” (read 2026-10-13)
The spoken lines and the end card follow your interface language across fifteen dialogue languages, with the cast and setting adapted to that market. The end card falls back to a language it can typeset when a script needs shaping or right-to-left layout.
SceneMixer, AI Ad Video Generator — “Which languages can the ad be in?” (read 2026-10-13)