On this page
- 01The short answer
- 02Diagnose the timing pattern
- 03Measure an offset with a recognisable word
- 04Fix a constant offset
- 05Fix gradual drift using two points
- 06Investigate a sudden change after a cut
- 07Check whether the problem is the caption track
- 08SRT versus VTT does not decide sync quality
- 09Verify the repaired file
- 10Sources
- 11Cite this page
The short answer
Short answer
Check subtitle timing near the beginning, middle and end of the video. If the error stays the same, shift the cues by a constant offset. If it grows, use a timing correction based on multiple reference points. If it changes suddenly after a scene or edit, check that the subtitles belong to this exact video version.
The first decision is the kind of error. Applying a single delay to a drifting file fixes one moment and leaves another wrong.
This guide covers subtitle files you can edit. Captions already burned into a video require changing the source project or producing another video export.
Diagnose the timing pattern
Every sentence is two seconds late
- Likely kind of mismatch
- Constant offset
- First repair to try
- Shift all cues earlier
Beginning is close, ending is much later
- Likely kind of mismatch
- Drift
- First repair to try
- Compare two distant reference points
Sync is good until a cut, then changes
- Likely kind of mismatch
- Version mismatch or a local edit
- First repair to try
- Check the corresponding scene and video version
Only a few cues are wrong
- Likely kind of mismatch
- Local timing errors
- First repair to try
- Adjust those cues individually
The file is correct in one player
- Likely kind of mismatch
- Playback or track-selection issue
- First repair to try
- Check the other player before rewriting the file
| What you observe | Likely kind of mismatch | First repair to try |
|---|---|---|
| Every sentence is two seconds late | Constant offset | Shift all cues earlier |
| Beginning is close, ending is much later | Drift | Compare two distant reference points |
| Sync is good until a cut, then changes | Version mismatch or a local edit | Check the corresponding scene and video version |
| Only a few cues are wrong | Local timing errors | Adjust those cues individually |
| The file is correct in one player | Playback or track-selection issue | Check the other player before rewriting the file |
Subtitle Edit documents shifting, selected-line adjustments and point-based synchronisation. Subtitle Tools explicitly warns that its whole-file shifter works only when the error is constant. Subtitle Edit timing tools, Subtitle Tools shifter limitations
These observations narrow the problem. They do not establish the original cause without inspecting the media and subtitle file.
Measure an offset with a recognisable word
Choose a clear sentence beginning. Avoid vague cues such as a long music passage or a subtitle describing a scene rather than speech.
Write down:
- When the spoken sentence starts in the video.
- When its subtitle begins.
- Whether the subtitle appears early or late.
Use the same time unit for both. A hypothetical example:
Spoken start: 12.400 seconds. Subtitle start: 14.900 seconds.
The cue is 2.500 seconds late. To move it onto the spoken start, the subtitle correction is:
12.400 - 14.900 = -2.500 seconds.
A tool asking for milliseconds would receive -2500 for an earlier shift. Check the tool's sign convention: “delay audio,” “delay subtitles,” and “shift subtitle times” are not always labelled the same way.
Measure at least one later sentence before applying that correction to the whole file.
Fix a constant offset
If the same error appears near the start and end:
- 1Save a copy of the original subtitle file.
- 2Shift all cue start and end times by the measured amount.
- 3Save to a new filename.
- 4Reload that file in the player.
- 5Check the first, middle and last cues.
Do not move only the start times. That changes cue duration instead of simply moving the captions earlier or later.
Check the beginning carefully after a negative shift. A cue must not end up with an invalid negative start time. If that happens, revisit the file's initial cues and the video's starting point.
A playback delay is useful for testing, but it is different from permanently rewriting the subtitle timestamps. Confirm which action your software performed before sending the file to someone else.
Fix gradual drift using two points
If the mismatch changes smoothly, record two pairs of times: one near the start and one near the end.
Here is a hypothetical example:
Early sentence
- Subtitle time
- 10 seconds
- Correct video time
- 12 seconds
Late sentence
- Subtitle time
- 610 seconds
- Correct video time
- 622 seconds
| Reference | Subtitle time | Correct video time |
|---|---|---|
| Early sentence | 10 seconds | 12 seconds |
| Late sentence | 610 seconds | 622 seconds |
The subtitle interval is 600 seconds. The correct video interval is 610 seconds. A simple linear mapping uses:
Scale = 610 / 600 = 1.0166667.
New time = 1.0166667 × old time + 1.8333333.
The offset is chosen so the first point maps to 12 seconds. The second maps to 622 seconds. This is arithmetic for the example, not a diagnosis that every drifting file needs exactly this transformation.
Use a subtitle editor's point-sync tool to apply the mapping, then check a third sentence in the middle. If that third point does not line up, the error may not be linear. Multiple edits, missing scenes or damaged timing can require selected-range correction instead.
Subtitle Edit describes visual synchronisation using early and late reference points. Subtitle Edit synchronisation documentation
Investigate a sudden change after a cut
A file that matches the first half and fails after one scene may belong to a different edit.
Compare the two versions for:
- An added introduction.
- A removed section.
- A different take.
- An inserted advertisement or intermission.
- A shorter ending.
- A change in playback speed.
A single global shift cannot compensate for an insertion halfway through a video. Correct the affected range only if the underlying dialogue still matches. If it does not, create captions from the final edit.
Do not stretch timings merely to hide a missing sentence. That can make the remaining cues look closer while the file still describes the wrong material.
Check whether the problem is the caption track
Before replacing a good file, confirm the player has loaded the intended one. Similar filenames and multiple language tracks can make this less obvious than it seems.
Try a local reference video with just the intended caption file. If it is correct there but wrong in a published player, investigate the published media version, caption upload and player settings.
Check whether the picture and sound are themselves aligned. If lips and speech drift before subtitles are displayed, the caption file may be exposing a video problem rather than causing it. Use the video frame-rate and audio-sync guide to examine that separate issue.
SRT versus VTT does not decide sync quality
Both SRT and VTT carry cue times. Converting a file changes its format; it does not automatically change the relationship between the words and the video.
Use the SRT versus VTT guide for destination compatibility. Diagnose the timing mismatch independently.
Likewise, a more capable speech model does not repair a caption file that belongs to an older edit. Confirm the source and final timeline before repeating transcription.
Verify the repaired file
Play the corrected file at normal speed and check:
- The first spoken sentence.
- A sentence after every major cut.
- At least one sentence around the middle.
- The final spoken sentence.
- Any cue with a short duration or overlapping neighbour.
Then review the complete file. Spot checks reveal the pattern, but they do not replace a final watch.
Keep the original and repaired files with explicit names. For your own footage, finish the edit before exporting final subtitles. If regeneration is the cleaner repair, follow the offline subtitle workflow against that exact video.
Sources
- Subtitle Edit timing toolsChecked October 13, 2026. See the linked documentation and the claim it supports in the article.
- Subtitle Tools shifter limitationsChecked October 13, 2026. See the linked documentation and the claim it supports in the article.
Cite this page
Last verified: Oct 13, 2026
Patel, O. (2026, October 13). How to fix subtitles that are out of sync. Rushilo. https://rushilo.com/blog/fix-subtitles-out-of-sync
About the author
Founder, Rushilo
Om Patel is the founder of Rushilo, a desktop video editor driven by the user's own AI, and of BigIdeasDB, a research platform that reads real complaints and reviews to help founders validate products. He writes Rushilo's research articles with the same method: primary sources, dated numbers and the words real users write.
