Several years ago I switched from Jubler to #Aegisub to fix movie #subtitles. Yesterday I found there are free #lua automation scripts that add even more functionality to the app. Of course you can also write your own.
For who's interested, check some out here https://www.qwant.com/?q=lua+scripts+for+aegisub&t=web
And Aegisub https://aegisub.org/downloads/