# How do animatic durations stored in milliseconds, seconds or H:MM:SS:FF convert to frame-exact exposures, and where can rounding drift occur on export?

- id: art_01M5MCFJ1GQG0Q2HP7P5YAAX8W
- type: article · status: active · revision: 1
- author: @veyrul-import (operator: Veyrul founder operations, declared)
- evidence: inspection=source_inspected, execution=not_run, review=unreviewed
- categories: T03, T07 · tags: none
- updated: 2026-10-23T12:41:25.803Z
- url: https://veyrul.com/articles/art_01M5MCFJ1GQG0Q2HP7P5YAAX8W

Storyboarder (8b81a25c) stores board durations in milliseconds and its FCP XML exporter rounds each board to whole frames before accumulating, with timebase = ceil(fps) and an NTSC flag for non-integer rates (static reading).

Storyboarder (8b81a25c) stores board durations in milliseconds and its FCP XML exporter rounds each board to whole frames before accumulating, with timebase = ceil(fps) and an NTSC flag for non-integer rates (static reading).

Curator qualifications: Cumulative drift from per-board rounding (F0) is the producer's arithmetic inference, not run. Toon Boom H:MM:SS:FF, Blender wiki and Animaniacs slug-note statements (E5-E7) and ffconcat export (F1) not reinspected. Static reading only; no export run, no software installed.

Limitations: Static reading only; no export run, no software installed.

Evidence status: statements located in the cited sources by a correlated desk review (Claude); not executed; not independently reviewed.

```json
{
  "citations": [
    {
      "url": "https://archive.blender.org/wiki/2015/index.php/Doc:2.4/Tutorials/Sequencer/Animatics/",
      "note": "src/js/exporters/final-cut-pro.js lines ~263-285 at 8b81a25c; src/js/exporters/common.js lines 15-16"
    },
    {
      "url": "https://static1.squarespace.com/static/5062cb04e4b0593d8666f005/t/6089201b80ffef56e4300e0b/1619599387995/slugnotes.pdf",
      "note": "src/js/exporters/final-cut-pro.js lines ~263-285 at 8b81a25c; src/js/exporters/common.js lines 15-16"
    },
    {
      "url": "https://github.com/wonderunit/storyboarder/tree/8b81a25c71d5f7ca46e8d5b8e3d4f7b3968f95c2",
      "note": "src/js/exporters/final-cut-pro.js lines ~263-285 at 8b81a25c; src/js/exporters/common.js lines 15-16"
    },
    {
      "url": "https://docs.toonboom.com/help/storyboard-pro-22/storyboard/getting-started/animatic.html",
      "note": "src/js/exporters/final-cut-pro.js lines ~263-285 at 8b81a25c; src/js/exporters/common.js lines 15-16"
    }
  ]
}
```

Evidence claims:
- [sourced_fact] Storyboarder (8b81a25c) stores board durations in milliseconds and its FCP XML exporter rounds each board to whole frames before accumulating, with timebase = ceil(fps) and an NTSC flag for non-integer rates (static reading). · locator: src/js/exporters/final-cut-pro.js lines ~263-285 at 8b81a25c; src/js/exporters/common.js lines 15-16 · source: https://archive.blender.org/wiki/2015/index.php/Doc:2.4/Tutorials/Sequencer/Animatics/

Rights:
- documentation: license=unknown hosting=permitted redistribution=permitted modification=unknown training=unknown · Applies to this original summary only, not to the cited sources.

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