Caption QA
This tool page isn’t translated yet — the working tool below runs in English. Use it in English
Timing desk
Find subtitle problems before viewers do.
Checks run locally. Caption text and optional preview audio stay on this device.
Find and replace
Spot overlaps and broken timestamps
TimingGo straight to the source block that caused each error.
Set your own delivery limits
ReadabilityChoose between Latin and CJK profiles, or add your own house-style limits.
You control editorial decisions
SafetyNo automatic retiming or rewriting. All meaningful corrections remain clear.
FAQ
Frequently asked questions
01 What does the caption checker test?
It spots invalid timestamps, overlaps, empty or duplicate cues, long lines, fast reading speeds, cues that are too short or long, and captions with more than two lines.
02 Are my subtitles uploaded?
No. Parsing, validation, editing, preview, and export all happen in your browser.
03 What reading speed should captions use?
The default is 20 visible characters per second for Latin scripts and 12 for CJK scripts. You can adjust both the reading-speed and line-length thresholds.
04 Does the tool automatically change subtitle timing?
No. Export safely normalises cue numbering, spacing, and timestamp separators, but it never silently changes timing or wording.
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