Choose Repair in Presentr Analyze, upload the video or audio and the subtitle file that is out of sync. The media is transcribed for word-level timings and each subtitle line it can match to the spoken words is moved to when it is actually said. You download a fixed SRT and VTT with your original wording, and a report of what moved.
1 credit a minute of media (for the transcription the timings come from).
No. Only the timings move.
Yes: the free SRT checker shows timing problems before you repair anything.