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Move every line earlier or later, fix subtitles that drift with two sync points or a frame-rate change, or let the video’s own speech line them up.
To sync subtitles, open the subtitle file here with its video, then either move every line with Earlier and Later, type a shift in milliseconds, or press Auto sync to match the lines to the speech it hears. When the lines are right at the start but wrong by the end, use Two-point sync: set one line near the start and one near the end, and the timings between them are stretched to fit. Download subtitles saves the corrected file.
SRT, VTT and ASS or SSA files all open, and the video is optional: without it you can still shift or convert the timing by a known amount. Like every tool here, it runs in your browser, so the film and its subtitles never leave your device. If the problem is the film’s sound rather than its subtitles, the audio sync fixer is the tool you want.
Drop the SRT or VTT file onto Drop subtitles to sync, then add the video when asked (Now add the video), or press Sync without the video if you only need a fixed shift.
Press Auto sync (A). It listens for speech in the video and moves the lines to match, then shows how far it moved them and a confidence of High, Medium or Low. Undo (Ctrl/⌘+Z) puts them back.
Use Earlier and Later ([ and ], 100 ms; Shift for 1 s; Alt for 10 ms) or type the Shift in milliseconds. For drift, pause where a line should start, pick it in the list and press Set this line to now (L), once near the start and once near the end, then Apply two-point sync.
Choose the Format (SRT or VTT; ASS stays available for ASS files) and press Download subtitles (D).
| What you see | Cause | Fix |
|---|---|---|
| Every line is early or late by the same amount | The subtitles were timed to a version with a different intro, logo or start | A shift: Earlier, Later or Shift in milliseconds |
| Fine at the start, worse and worse later | Made for a different frame rate, or a different speed of the film | Frame rate under More options, or Two-point sync |
| Fine for a while, then suddenly off | A scene was cut or added in your version | Split the problem: sync up to the cut, then shift the rest in a player; one straight-line fix can’t follow a cut |
Films shot at 24 frames per second are often broadcast in Europe at 25, which makes them about 4 % shorter. Subtitles timed for one release then drift steadily against the other. The Frame rate presets convert between 23.976, 24, 25 and 29.97 in one step.
Auto sync listens to the video’s soundtrack for speech: the energy in the voice band, measured against a background level that adapts to music and noise. It then slides the subtitle timings past that speech pattern to find where the lines and the talking overlap best, tries the common frame-rate speeds too, and finally checks several stretches of the film to catch a slow drift. It all runs in a background worker on your device.
.sub files and image subtitles (from DVDs and Blu-rays) aren’t supported.Most players can delay subtitles for one viewing. In VLC, the G and H keys move subtitles by 50 ms, and Tools → Track Synchronization takes an exact value; see the VLC guide. That setting lasts only while the player is open. Fixing the file means it plays right everywhere, on every device and every time.
They were timed for a slightly different version of the video: one with a different opening, a different frame rate or a few scenes cut. A shift fixes the first, a frame-rate change or two-point sync fixes the second.
Yes, when you add the video. Auto sync matches the lines to the speech it hears and reports how confident it is. Check a few lines in different places before downloading.
No. Without it you can shift the timing by a known amount or convert the frame rate. The video is needed for Auto sync and for watching the lines play in place.
SRT, WebVTT and ASS or SSA. You can save SRT or VTT, and ASS files can be saved as ASS too.
No. Only the times change. Text, line breaks and styling tags stay as they were.
No. Both are read by your browser on your device. Nothing is sent anywhere.