Sync subtitles that drift further off as the film goes on
Pick one line near the start and one near the end, enter the moment each is actually spoken in your video, and every line is moved and stretched to fit.
How it works
Drift comes from the subtitles being timed for a release that runs at a slightly different speed. A shift cannot fix it, because the error grows: barely noticeable in the first minutes, many seconds by the end. Two points fix both the speed and the offset at once — the same correction is applied to every line, so the ones between the two points land where they belong.
Play your video, pause on a line near the beginning and note the time on the player; do the same near the end. In the table, click those two lines and use “Sync: this is line 1” and “Sync: this is line 2” — the time box is filled with the current timing, so only a few digits need changing.
It names the cause too
When the correction is exactly the ratio between two common frame rates — 25 and 23.976, the difference between European TV and Blu-ray — the page says so. Next time a file from the same source drifts, changing the frame rate fixes it in one step, without measuring anything.
If the lines are off by the same amount all the way through, a simple shift is quicker.
Questions
- How far apart should the two lines be?
- As far as possible — the first line with speech and one in the last few minutes. Two lines a minute apart amplify any small mistake over the rest of the film.
- The ending is right but the middle is off.
- Then the film itself is different in the middle — a scene was cut or added. Sync by the first and last lines before the cut, then shift the rest from the line after it.