Shift a section of subtitles
Move a chosen range of subtitles and leave the rest exactly where it is — the fix for a file that starts in sync and slips partway through, like after an ad break or a missing scene.
The AI Subtitle Studio desktop app has this same Tools section built in — plus AI transcription, translation and batch processing for a whole season at once, all running locally on your Mac or PC.
Find the break, set the range
Find where it slips
Play the video and note the subtitle number where the drift starts — everything before it is fine, everything after is off by the same amount.
Set the range and offset
Enter the subtitle numbers to shift and by how much. Leave "last" blank to mean "to the end of the file."
Download the result
Get the file back with only that range re-timed — everything outside it is untouched, down to the byte.
Multiple ranges, in order
Add another range adds a row. A file with three ad breaks needs three ranges, each with a bigger offset than the last, since the error accumulates over the length of the file.
Where two ranges overlap, the first one wins — a subtitle covered by more than one row takes the offset from the row nearest the top and ignores the rest, so ranges never stack. Order your rows from most specific to most general if you use overlapping ones on purpose. A row left at the default 0-second offset doesn't count for this — it's treated as not yet set, so an overlapping row below it still applies.