Which pauses in dialogue must an audio describer use under WCAG, and what makes a pause unusable (under about 2 seconds, far from the visual event, important non-speech audio)?

Problem. Describers need a testable rule for when a dialogue pause must carry description and when it should be left alone. Conditions. Standard (non-extended) audio description of prerecorded synchronized media, WCAG 1.2.5 (AA). Method. WCAG failure F113 says important actions, characters, scene changes and on-screen text conveyed only visually need appropriate pauses in dialogue. It notes that not all pauses are usable: pauses that are too short (example given: under 2 seconds) or not near the visual content may be unsuitable. Where visual information coincides with music or sound effects, audio ducking (lowering the overall level) can make added narration easier to distinguish. The test has two checks: all missing important visual information is conveyed, and no remaining pause in dialogue is one where description would be appropriate. Failure modes. Ducking can mask non-spoken audio that carries much of the sense of the video; some pauses should not be filled because the non-spoken audio is too important. Leaving usable pauses unused while visual information stays undescribed fails 1.2.5. Limitations. The 2 seconds figure is given as an instance ('for instance'), not a fixed threshold; the page gives no words-per-second or lead/trail margin. Version/date. WCAG 2.2 technique page as fetched. Curator qualifications: All cited documentation excerpts located on the live pages by curator GET; no video sources. Limitations: The 2 second figure is an example in a non-normative technique, not a requirement; what counts as 'in proximity' is not quantified. DCMP Description Key (HTTP 403 to curl) and the ACB ADP guideline pages (404 at tried URLs) could not be fetched, so no DCMP/ACB gap-timing rule is claimed here; only W3C WCAG 2.2 pages were read. Evidence status: statements located in the cited sources by a correlated desk review (Claude); not executed; not independently reviewed.

{
  "citations": [
    {
      "url": "https://www.w3.org/WAI/WCAG22/Techniques/failures/F113",
      "note": "Description, first Note; Description; Description; Description, second Note; Tests, Procedure; n/a"
    }
  ]
}