subtitle-caption

Subtitle & Caption Skill

Subtitles fail when they're too long to read before they vanish, badly segmented, or a literal

translation that overruns the timing. Good subtitling obeys real constraints: reading speed (≈17

chars/sec / ~160–180 wpm), line length (~42 chars), max 2 lines, and sentence-aware segmentation.

This skill writes or translates captions to those rules — readable, well-timed, and condensed to fit.

Required Inputs

Ask for these only if they aren't already provided:

• The content — a transcript, script, or existing subtitles (with timecodes if you have them).
• Task — caption (same language), translate-subtitle (to another language), or SDH (deaf/HOH captions with sound cues).
• Format — SRT, WebVTT, or plain; and any platform limits (YouTube, broadcast, Netflix-style specs).
• Constraints — reading-speed/line-length target if non-standard.

Output Format

Subtitles: [content] — [task]

The subtitles in the requested format (SRT/VTT), each cue:

• ≤2 lines, each ~42 chars, broken at natural phrase boundaries (don't split an article from its noun).
• Timed to reading speed — long sentences are condensed (not every word — paraphrase to the gist) so they're readable in the time available. Where you have timecodes, respect them; where not, note suggested durations.
• For translation: render meaning compactly — the target must fit the same time slot, so condense more aggressively than prose translation, keeping the essential meaning.
• For SDH: include speaker IDs and [sound cues] (e.g. [door slams], [tense music]).

Notes — where you condensed/cut and why, any cue that's tight on reading speed (a 🔴 flag to adjust timing), and segmentation choices.

Quality Checks

• [ ] Each cue is ≤2 lines and within the line-length limit (~42 chars)
• [ ] Cues are readable at standard reading speed — long lines are condensed, not crammed
• [ ] Line breaks fall at natural phrase boundaries (no orphaned articles/prepositions)
• [ ] Translations are condensed to fit the original timing, keeping the meaning
• [ ] SDH captions include speaker IDs and sound cues where requested
• [ ] Output is in the requested format (valid SRT/VTT structure)

Anti-Patterns

• [ ] Do not exceed reading speed — a perfectly accurate caption no one can read in time has failed
• [ ] Do not translate verbatim for subtitles — the target overruns the slot; condense to the gist
• [ ] Do not break lines mid-phrase — split at clause/phrase boundaries for readability
• [ ] Do not exceed 2 lines per cue — split into multiple cues instead
• [ ] Do not omit sound cues in SDH — they're the point of accessible captions

Based On

Subtitling standards — reading-speed (CPS) limits, ~42-char lines, 2-line max, phrase-boundary segmentation, SDH conventions.