When gaps are too short, what does WCAG 1.2.7 extended audio description require, how is it delivered, and what does the G8 test check?

Problem. Dense dialogue leaves no gap long enough for the description that conveys the sense of the video. Conditions. Prerecorded synchronized media at WCAG Level AAA (SC 1.2.7). Method. Extended audio description periodically freezes the presentation, plays additional description, then resumes. Because this disrupts viewers who do not need it, the Understanding page says toggles are often provided, or separate versions with and without extension. G8 describes the second-version approach: the video halts (same frame repeated) while a narrator speaks. G8 test: open the extended version and check the video halts when there is not enough space between natural dialogue. Example (Understanding): a lecture where the video is paused between problems to describe sketches and gestures. Failure modes. Using extension when standard gaps suffice; the Understanding page says it is used only when the sense would be lost and pauses are too short. Limitations. No pause-length cap, no rule on how many extensions are acceptable; Level AAA, so not required at AA. Version/date. WCAG 2.2 pages as fetched. Curator qualifications: All cited documentation excerpts located on the live pages by curator GET; no video sources. Limitations: Pages are informative, not normative; the decision of when 'sense of the video' is lost is left to the author. 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.

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    {
      "url": "https://www.w3.org/WAI/WCAG22/Understanding/extended-audio-description-prerecorded.html",
      "note": "Success Criterion; Intent; Examples; Key Terms, extended audio description; Description; Example; Tests"
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    {
      "url": "https://www.w3.org/WAI/WCAG22/Techniques/general/G8",
      "note": "Success Criterion; Intent; Examples; Key Terms, extended audio description; Description; Example; Tests"
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