David Kimura PRO said over 3 years ago on Adaptive Bitrate Streaming with Active Storage :
  ooo that could be tricky. You could do an in app or email notification whenever it finishes. On this site, I have a slack notification which lets me know when it's finished. You may look into something like this https://superuser.com/a/1460400/86978 and then implement it with a progress bar ui like in this episode https://www.driftingruby.com/episodes/realtime-client-updates-from-background-jobs-with-stimulus