Sync subtitles (shift timing and change FPS)
Shift every subtitle in an SRT, VTT, ASS or SSA file earlier or later, and fix drift between 23.976, 24, 25 and 30 FPS.
Processed on your device: your file never leaves your computer
Up to 50 files, 10 MB max each.
What Sync subtitles (shift timing and change FPS) does
Subtitle sync fixes files that show up before or after the words are spoken. Type how many seconds to move them (a negative number makes them earlier) and, if the gap keeps growing during the film, change the frame rate: the classic case is a subtitle made for 23.976 FPS on a 25 FPS video. Only the timings change: the file's format, styles, positions and comments stay untouched. No timing ends up before the start of the video.
Limits
- Up to 50 files at a time, up to 10 MB each.
- With Pro: up to 500 files per batch.
- A job that takes longer than 1 minute is stopped so it doesn't freeze your device.
- Processed in your browser: your files are never uploaded to a server.
Frequently asked questions
How do I know how many seconds to shift?
Find a clear line in the video, note the second it is spoken and compare it with that line's time in the subtitle file. If the subtitle shows up 2 seconds late, type -2; if it shows up early, a positive number.
It matches at the start but drifts by the end. What should I do?
That is a frame rate problem: the subtitle was made for another release of the video. Turn on "Change the frame rate" and choose the source and target rates; the most common pairs are 23.976 ↔ 25.
What happens to lines that would land before the start?
Lines ending before second zero are removed (we tell you how many) and lines crossing it start at zero. SRT cues are renumbered.
Will my ASS file lose its styles?
No. Only each line's start and end times are rewritten; styles, positions, effects and comments stay as they were.