Change subtitle framerate
Convert subtitle timing between framerates — 23.976, 24, 25, 29.97, 30 and more. Fixes PAL speed-up drift in your browser, with no upload.
A subtitle file timed against a 25fps PAL transfer will run steadily ahead of the same film at 23.976fps, and no amount of shifting fixes it: the error grows with every minute because the two videos run at different speeds, not at different starting points. The correction is proportional, and it is arithmetic rather than guesswork — every timestamp is scaled by the ratio between the two rates. Pick where the file came from and where it is going, and the whole track is re-timed at once.
Worth knowing
- The classic case is PAL speed-up: 25 against 23.976 is a 4.27% difference, which is two minutes and thirty-four seconds by the end of an hour and over five minutes across a feature.
- This scales timing; it does not re-cut it. The dialogue, the line breaks and the order of the cues are untouched — only the numbers move.
- If the drift is not proportional — subtitles that are right at the start, wrong in the middle and right again at the end — the cause is edited content, not framerate. Two-point sync handles that; a framerate change will not.
- A 29.97 to 30 conversion changes timing by only 0.1%, about three and a half seconds across a feature film. It is real, but if your subtitles are seconds out from the first line, look for an offset instead.
FAQ
How do I find out what framerate my video is?
Most players show it in a file information or codec panel — VLC lists it under Tools, Codec Information. Failing that, try the conversion both ways: the correct one holds sync from the first line to the last, and the wrong one drifts visibly within a few minutes.
My subtitles are late by the same amount all the way through instead. What then?
That is an offset, not a framerate problem, and it is fixed by shifting every cue by a constant. Use the shift tool — you can set the amount by playing your own video and marking where a line should have appeared.