Fix subtitles that start right and drift out by the end. That is a frame-rate mismatch rather than a delay: the error grows as the file plays, so shifting every line by a fixed amount cannot fix it. Pin two lines to the times they should really appear — one near the start, one near the end — and every cue between them is stretched to match. If your subtitles are simply early or late by a constant amount, the subtitle shifter is the tool you want instead.
How it works
- Drop the .srt, .vtt, .ass or .sub file. Add the video or audio as well if you have it, and you can hear exactly when each line should land.
- Pick two cues, far apart, and enter the time each one should really appear at. The stretch factor, the offset and the corrected end time are all shown before anything is exported.
- Download the corrected file, in the format it arrived in.
Questions
- What is the difference between resyncing and shifting?
- A SHIFT adds the same offset to every cue: right when the subtitles are uniformly two seconds early, from the first line to the last. A RESYNC stretches the timeline: right when they line up at the start and are half a minute out by the end, which is what a 25 fps subtitle file played against a 23.976 fps encode does. If line one is already wrong, you want the shifter; if line one is right and the last line is not, you want this page.
- Why does it need two anchors?
- Two points define a line. One correction says how far off the subtitles are at a single moment, which is a shift; two say how the error GROWS, which is what drift is. Pick them as far apart as you can — anchors thirty seconds apart in a two-hour film amplify every small mistake in your timings, and the tool warns you when they are too close to trust.
- Does my file get uploaded?
- No. The models and all processing run inside your browser on your own device. You can verify this yourself: open your browser’s DevTools, watch the Network tab, and process a file: there are no uploads. After the first visit most tools also work fully offline.
- What is a two-point resync?
- A fixed shift fixes subtitles that are uniformly early or late, but not ones that drift further out over the runtime (a frame-rate mismatch). Pin the first and last line to their correct moments and every cue between them is stretched linearly. That is the standard fix, done locally.
- How does on-device translation work?
- Recent Chromium browsers ship a built-in translator that downloads language packs and runs locally. Where your browser offers it, this tool uses it, subtitle text included, and nothing is sent to a service. Where it does not, the page says so instead of quietly uploading.
- Burned-in vs a subtitle file: which do I want?
- A separate .srt/.vtt can be toggled and edited, and players render it crisply, so prefer it where you control playback. Burn-in re-encodes the video with the text drawn into the frames: it plays everywhere and cannot be turned off.