Captions · Free browser tool
Subtitle timing shifter: fix SRT and VTT sync
Use a positive offset for later captions and a negative offset for earlier captions. Time scale multiplies timestamps before the offset is added. Diagnose the mismatch before changing the file.
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How to use it
- 01
Measure the error
Check a recognizable word near the start and end. The same delay suggests an offset; a growing mismatch needs closer diagnosis.
- 02
Set the correction
Keep time scale at 1 for an ordinary shift. Enter a known scale only when the error is proportional.
- 03
Review the result
Starts before zero are clamped; cues that finish before zero are omitted with a warning. Test against the actual final video.
A worked example
With time scale 1 and offset +1.5 seconds, a cue starting at 10 seconds starts at 11.5 seconds. Scale 1.01 maps 100 seconds to 101 before any offset.
What to check
- The tool changes subtitles, not the video's playback speed. A sudden mismatch after a cut often needs section-specific edits.
- VTT cue settings and blocks are retained. Embedded karaoke timestamps are shifted too; special header metadata is not retained.
- The original file is not overwritten. Download and review a separate copy.
Questions
Should a negative shift delete captions?
A cue ending at or before zero has no remaining positive display time and is omitted. A cue crossing zero starts at zero. The tool lists those changes before download.
Will one shift fix every timing problem?
No. Different cuts, video versions or nonlinear timing errors require different corrections. Keep a copy and inspect the beginning, middle and end.
Continue the workflow
Sources and format guidance
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