Accessibility · official-source review · reviewed 2026-10-09
Captions that drift two seconds early still read as broken, and viewers blame the video instead of the file.
Compare caption timing offsets across a video and log the cues that drift past your tolerance.
Editors and course authors checking caption files before publish.
Use the source document or official route that applies to your situation. This guide does not contact another person or verify external information.
Play the video with captions on and note early or late cues.
Record the offset in seconds for each failing cue.
Set the tolerance you consider acceptable for publish.
Retime only the cues that exceed the tolerance.
Four checked cues with a 2.4-second worst offset exceed a 1.5-second tolerance. The checker lists the failing cue.
Use your own source and details. The example is not a record about a real person or organization.
World Wide Web Consortium, Web Accessibility Initiative · reviewed 2026-10-09
What this source supports: Captions provide text for speech and important sounds. Review automatic captions and correct errors before release.
Source limit: A checklist cannot certify legal compliance or replace review by people who use captions. Requirements depend on content and context.
These sources support the statements above. They do not show that every person needs this guide. They do not show a specific result.
This guide checks the offsets you enter. It does not parse subtitle files, retime cues, or validate playback platforms.
A checklist cannot certify legal compliance or replace review by people who use captions. Requirements depend on content and context.
Use current instructions from the responsible organization. This guide is a planning aid, not an official decision or a substitute for qualified advice.
Compare the worst cue offsets with your tolerance and list which cues need retiming.
This App compares offsets you enter. It does not parse caption files, retime cues, or check player behavior.
You enter every number yourself. The sources support the method and the limits. They do not produce a result for your specific case. Keep the original documents next to the sheet you build.
The App computes the worked example with your own numbers, in your browser.
APP 1
Compare the worst cue offsets with your tolerance and list which cues need retiming.
Free · no account · no upload
Open Caption Timing Drift CheckerThe App runs in this browser. It does not send or save entries. Copy, download, or print only when you choose.
This guide uses short, direct instructions as an ASD-STE100-style writing target. It is not a formal certification.
Companion App: Caption Timing Drift Checker. It runs in this browser and does not upload your entries.
This guide is edited for clarity and checked against the sources it links. It is not a substitute for official instructions or qualified advice. A linked source does not show that every person needs this guide.