Question 1

How do I know whether to shift or resync?

Accepted Answer

Watch the start and the end. If both are out by the same amount, shift. If the start is right but the end is noticeably out - or the gap grows as you go - resync by two lines. Frame rate conversion is the same fix when you already know the two rates, typically 25 and 23.976.

Question 2

What happens to lines that would start before the video?

Accepted Answer

Shifting earlier can push the first lines before zero. Any line that would finish before the video starts is removed, one that straddles zero is cut to start at zero, and the page says how many were affected. Undo puts them back.

Question 3

Can it convert SRT to VTT?

Accepted Answer

Yes - open either and save as the other. The text and timing carry over; WebVTT position settings are kept when saving as .vtt and dropped from .srt, which has nowhere to put them.

Question 4

Does the video get uploaded?

Accepted Answer

No. The video is played by your browser from the file on your computer, and the subtitles are rewritten in the page. A film can be gigabytes; nothing here would want it on a server.

Free subtitle sync fixer