Free · No sign-up · Local browser processing
Fix subtitle timestamps and growing SRT/VTT drift
Captions all early or late? Use a fixed offset. If subtitles drift further out of sync as a video plays, use two-point resync: give the corrected start times for the first and last cues. Changes stay in your browser.
Play the video and note when the first and last subtitle lines really start. Enter those correct times in seconds, e.g. 2.250 or 3600.125. The original time of each anchor comes from your subtitle file.
Two-point sync corrects linear drift, not incorrect individual words or irregular timing. At least two cues with distinct start times are required. Times outside the supported range are rejected, never clipped.
Ready. Nothing uploaded.
Keep your original file. Structural checks do not guarantee audio synchronization or speech accuracy.
A constant offset
Every valid cue start and end is changed by the same number of seconds, with millisecond precision. Subtitle words are not changed.
Two-point resync for progressively incorrect timestamps
Choose two-point resync when the delay grows across the video. Check the speech time of your first and last subtitle cues, then enter those corrected times in decimal seconds. The tool proportionally adjusts every cue; review the output against the recording.
Negative-time protection
The tool refuses any shift or two-point correction that would move cues before zero, reverse a cue or make a timestamp unsupported, rather than silently clipping or removing it.
Frequently asked questions
Does a plus sign delay subtitles?
Yes. Enter +2 to show captions two seconds later.
How do I fix subtitle timestamps?
For a constant delay use Shift all captions, entering positive seconds to show text later or negative seconds for earlier. For growing delay choose Resync two points, find the true playback time of the first and last cues and enter those two times. Download the repaired SRT/VTT and verify it against the video.
Can I fix drift from a different frame rate?
Yes, when the drift is approximately linear: two-point resync stretches the timeline between two corrected cue starts. It does not listen to speech or identify correct anchor times automatically. Check the beginning, middle and end after downloading.
Will text change?
No. Only valid timestamp values are changed; original cue words and line breaks remain intact.
Need new captions from speech?
Generate SRT subtitles from video/audio with LongScribe, then choose a converter, validator or timing repair tool for the downloaded file.