How should I break caption lines and split long sentences across events?

Problem. Auto line wrapping breaks mid-phrase and hurts comprehension. Conditions. Any caption or subtitle with more than one line or event per sentence. Method. Documented: break after punctuation, before conjunctions and before prepositions (Netflix); do not separate article from noun, adjective from noun, first from last name, subject pronoun from verb, prepositional verb from preposition, verb from auxiliary/reflexive/negation. Prefer a bottom-heavy pyramid, avoid one or two words alone on the top line (Netflix English). BBC: ideal break at punctuation; each subtitle should be a single sentence, but a long sentence may extend across several subtitles, segmented at clause boundaries in preference to phrase boundaries; BBC also says well-edited text and timing matter more than perfect line breaks. Netflix: when one sentence continues across continuous subtitles, no ellipsis or dash is used if the pause is under 2 seconds. Example. BBC's own long-sentence example breaks after 'When I jumped on the bus' (clause boundary). Failure modes. Treating the limit as a fixed character count only; BBC notes that proportional fonts make width, not count, decisive. Limitations. Rules are written for English; other Netflix languages have their own rules (see C2-B30-G4-08). Version/date. Pages as fetched 2026-10-24. Inference: an automatic breaker can score candidate breaks by the Netflix 'do not separate' list using a POS tagger or a rule list, and choose the lowest-cost break that satisfies the width limit; none of the sources describes an algorithm. Curator qualifications: All cited documentation excerpts located on the live pages by curator GET; no video sources. Limitations: Both guides are English-centric. BBC page wording on width depends on region and font, which an ASR pipeline cannot know without the player. 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.10 Line Treatment; 4. Line Treatment; 3.9 Long sentences; 3.10; I.3 Continuity; researcher reasoning"
    },
    {
      "url": "https://partnerhelp.netflixstudios.com/hc/en-us/articles/215758617-Timed-Text-Style-Guide-General-Requirements",
      "note": "I.10 Line Treatment; 4. Line Treatment; 3.9 Long sentences; 3.10; I.3 Continuity; researcher reasoning"
    },
    {
      "url": "https://www.bbc.co.uk/accessibility/forproducts/guides/subtitles",
      "note": "I.10 Line Treatment; 4. Line Treatment; 3.9 Long sentences; 3.10; I.3 Continuity; researcher reasoning"
    }
  ]
}