If every caption appears late by the same amount, a shift can repair the file. If the delay grows as the video plays, a single offset will only fix one section. Diagnose that difference before applying a correction to every cue.
Measure the error in several places
Choose a clear spoken phrase near the beginning. Compare the moment you hear it with the moment its cue appears. Use the first audible word rather than a visual gesture that may occur before or after the speech.
Repeat the comparison in the middle and near the end. If the difference is broadly the same, a whole-file shift is appropriate. If the captions gradually move farther from the speech, investigate a mismatched source version, timing scale or frame-rate conversion.
A sudden jump in delay often means somebody cut a section from the video after captions were made. A global shift cannot fix both sides of that cut. Repair the affected section in the editor or return to captions produced for this exact export.
Free tools for this
Free to use, no account needed.
- Subtitle timing shifterMove captions earlier or later, from one point onward, or stretch them to fix drift.
- Subtitle editorFix caption text and timing line by line, with your video playing alongside.
- Subtitle readability checkerCheck a caption file for lines that are too long, too fast, too short or overlapping, and fix them.
Apply the offset with the correct sign
Do not repeatedly shift the last shifted version while losing track of the total. Record the correction and apply a new attempt to the original. That keeps the timing change reproducible and avoids accumulating an accidental offset.
- Open the shifter with the original caption file. Keep an unchanged copy so you can reverse a mistaken correction.
- If captions are early, shift them later with a positive offset. If captions are late, shift them earlier with a negative offset. Read the page’s unit label before entering the value.
- Run the shift and inspect the first cue. Moving cues before the beginning can require clamping or removal; check what happened rather than assuming every cue stayed intact.
- Download the shifted file and load it with the exact video you measured. Check the same opening, middle and closing phrases.
- If one offset does not fit all sections, stop shifting the entire file. Use targeted edits or rebuild timing from the correct source.
Check local cue boundaries too
Synchronization is not the same as readability. A cue can appear at exactly the right time yet be too dense to read. After fixing delay, run the reading-speed check and review long cues in context.
- Check that a cue appears with the phrase it represents, not during the preceding speaker’s last words.
- Watch the transition between adjacent cues. A cue that starts correctly but disappears too early may need a duration correction rather than another global shift.
- Look for captions that remain on screen after a scene change or over a different statement.
- Check cues close to the start and end of the file. Negative shifts can expose boundary cases that do not occur in the middle.
- Play the saved captions in the receiving player, because its presentation may differ from a local preview.
Find the reason before the next edit
Tie captions to a named video version. If an editor removes an introduction or inserts a title card, update timing before reusing the old caption file.
If a file is consistently wrong only in a particular player, check that player’s own subtitle-delay setting. A local playback offset can make a correct file appear broken. Reset it before judging a new export.
When the recording and captions came from different sources, do not assume their opening titles or cuts match. Compare the actual content. Regenerating captions from the correct recording may be safer than trying to repair an unknown sequence of edits.
Questions about this workflow
Which sign moves early captions later?
A positive shift delays them. A negative shift makes them appear earlier. Check the unit shown beside the field.
Why does the end remain wrong after I fixed the start?
The error may be drift or a timeline edit, not a constant delay. Measure another section before changing the offset again.
Can the checker synchronize captions automatically?
No. It flags structural and reading issues. Compare the cues with the actual speech to establish synchronization.
Want captions without the cleanup?
Studio captions every word you said, a few words at a time, and changes any line you ask about in plain words.
