How should speakers and non-speech sounds be labelled in captions, and how does that map from diarization output?

Problem. Diarization gives anonymous speaker ids and no sound events. Conditions. SDH or captions for viewers who cannot hear audio. Method. Documented (Netflix English SDH): speaker IDs and sound effects go in square brackets; use IDs only when the speaker cannot be visually identified; if the name is not yet known use [man] or [woman] and add numbers such as [man 1]; two speakers in one subtitle use a hyphen without space and at most one speaker per line; the ID goes on the same line as the dialogue; describe sounds, not visuals; plot-pertinent sound effects included unless inferred from the visuals; never italicise labels. Music: lyrics between music notes, unknown song titles omitted and music described. BBC: colour is the preferred way to separate speakers, dashes are legacy and used with white text, single quotes mark out-of-vision speakers, and ttm:agent metadata may carry speaker information. Failure modes. Labelling every sound clutters the 20 cps budget; a wrong name given too early leaks plot (Netflix [man]/[woman] rule). Limitations. Netflix and BBC differ (brackets and hyphens vs colour); pick one per platform. Version/date. Pages as fetched 2026-10-24. Inference: map diarization ids to labels only after a name or role is confirmed from the content; otherwise emit [man 1]/[woman 2]; audio-event classifiers are not covered by these sources. Curator qualifications: All cited documentation excerpts located on the live pages by curator GET; no video sources. Limitations: Overlapping speech is poorly handled by both guides and by ASR; no numeric limit on label length. Evidence status: statements located in the cited sources by a correlated desk review (Claude); not executed; not independently reviewed.

{
  "citations": [
    {
      "url": "https://partnerhelp.netflixstudios.com/hc/en-us/articles/217350977-English-Timed-Text-Style-Guide",
      "note": "I.16 Speaker ID / Sound Effects; I.16; I.16; I.6 Dual Speakers; 7 Identifying speakers; 7.9; researcher reasoning"
    },
    {
      "url": "https://www.bbc.co.uk/accessibility/forproducts/guides/subtitles",
      "note": "I.16 Speaker ID / Sound Effects; I.16; I.16; I.6 Dual Speakers; 7 Identifying speakers; 7.9; researcher reasoning"
    }
  ]
}