Subtitle and Video Sync Problem
If you have a synchronization problem between the subtitle and the video, that is, the subtitle synchronization problem, and this is not from FPS, you can fix it with the help of the keyboard.
Open the video and embed the subtitle. Later ; and . Synchronize the subtitle with the marks.
; (semicolon) key : retracts the subtitle 0.5 seconds.
. (dot) key : moves the subtitle forward 0.5 seconds.
If the sync is broken again after 1-2 minutes even though the sync is set, there is an FPS problem here. In other words, Video FPS and Subtitle FPS do not match. Therefore, there is constant slippage.