Subtitle readability: why a valid file can still be unreadable

Short summary

A subtitle file can pass every technical validator and still be unreadable. The article identifies four failure modes that validators miss: bad line breaks that split phrases at emphasis points, reading-speed ceilings exceeded by fast narration, display rhythm issues like flicker or lingering lines, and language-specific challenges with German compounds and CJK scripts. Practical checks are provided for each, including muting audio to test readability cold and targeting the three fastest lines for review.

• •Validators catch syntax and timing errors but miss human readability factors like line-break placement and reading speed
• •Netflix caps English adult content at 20 cps and children's at 17; WCAG deliberately sets no cps figure
• •Practical checks: read line breaks in isolation, mute audio and test fastest lines cold, watch for sub-500ms flicker and 8s lingering lines

Generated with AI, which can make mistakes.