Letterbox and pillarbox: padding a shape mismatch
Letterboxing adds bars above and below a picture; pillarboxing adds them at the sides. Both are ways of fitting a file into a shape it was not generated for, and both trade a correct specification for a smaller picture. As of 2026-09-12.
| Approach | What it preserves | What it costs |
|---|---|---|
| Letterbox or pillarbox | The whole composition | Screen area, and the look of a mistake |
| Crop | The delivered shape, fully filled | Whatever falls outside the new rectangle |
| Generate for the shape | Both | A second generation |
Inclusion rule. Ways a finished piece can be made to satisfy a shape requirement it was not made for, with what each one preserves. Order. Cheapest approach first.
1Padding satisfies the specification and not the brief
A padded file has the right dimensions and the right ratio, so it uploads. What it does not have is a full frame, and on a vertical surface a letterboxed widescreen piece occupies a strip in the middle of a phone screen.
Against content that fills the frame, that reads as an advertisement that was made for somewhere else. It is the cheapest fix and the one most visible to a viewer.
2Cropping trades the other way
A crop fills the frame and throws away whatever sits outside the new rectangle. Where the subject was centred it survives; where it was placed by thirds it moves to the edge or out of the picture entirely.
So the choice between padding and cropping is a choice about which kind of damage is less noticeable, and both are decided by how the shot was staged rather than by how the conversion is done.
3Generating per shape is the approach that keeps both
Where a page publishes several shapes as a parameter, each surface gets its own staging, the frame is full and the composition is intact. The cost is another generation rather than another export.
That is the practical value of a long shape list, and it holds regardless of picture quality. Six entries on these sheets publish no shape whatever, and for those the padding or cropping decision is the only one available.
A vocabulary entry: the definition, plus how the specification pages on these sheets usually publish it. Table checked 2026-09-12. Nearby entries: Autoplay, Prompt and audio driven.
4From brief to placement
For ad work around “Letterbox and pillarbox”, SceneMixer's pages explain how its ad projects are produced:
On a segment’s card, Insert adds a blank segment right after it: write its header and shots.
SceneMixer, Inserting and Deleting Segments (read 2026-10-13)
Character sheets are always portrait and scene images always widescreen, whatever ratio the videos use.
SceneMixer, Vertical 9:16 or Landscape 16:9 — “Will choosing 9:16 make my character images vertical?” (read 2026-10-13)