Broadcast Captioning & Subtitle Style Guide

# Broadcast Captioning & Subtitle Style Guide A production standard for clean, accessible, and legible video subtitles and closed captions across broadcast and streaming media. --- ## 📏 Core Structural Limits Adhere strictly to industry broadcast constraints to ensure viewers can comfortably read cues without obscuring visual content: | Metric | Target Specification | Hard Maximum / Limit | | :--- | :--- | :--- | | **Lines per Subtitle** | 1 to 2 lines | **At most 2 lines** | | **Line Length** | 35 to 40 characters | **About 42 characters per line** | | **Reading Speed** | 15 to 17 characters/sec | **Under about 21 characters a second** | | **Display Duration** | 1.5 to 4.0 seconds | **At least 700 ms minimum** | --- ## ✂️ Line Break Principles Never divide text arbitrarily based on character counts alone. Subtitle breaks should align with natural speech cadences and syntactic units: 1. **Keep prepositional phrases together**: - *Poor:* We went into the / room quietly. - *Preferred:* We went / into the room quietly. 2. **Do not separate auxiliary verbs from principal verbs**: - *Poor:* She has / completed the full inspection. - *Preferred:* She has completed / the full inspection. 3. **Keep proper nouns and compound names on a single line**: - *Poor:* We consulted Dr. / Evelyn Wright on Friday. - *Preferred:* We consulted Dr. Evelyn Wright / on Friday. --- ## ⏱️ Timing & Pacing Guidelines - **Shot Changes**: When dialogue continues across a hard video cut, place the subtitle in point either directly on the cut or at least 2 frames before/after. Avoid hanging a subtitle across a cut for fewer than 3 frames. - **Minimum Gap**: Maintain a minimum gap of at least 2 to 4 frames (approx. 80–160 ms) between consecutive subtitle events to allow viewers to register cue transitions. - **Synchronicity**: Dialogue cues should appear within 100 ms of the first acoustic onset of speech.