Does subtitle offset not work for SUP subtitles?

[OttoKerner]

sup contains pictures, just like PGS and VOBSUB.
Subtitle offset in Plex works only for subs in text format. i.e. SRT or similar.

If you can’t find a fitting text-format sub for that video, maybe this is an option:

Introduction: convert image-based subtitles to SRT with Subtitle Edit

This is a short introduction into how to convert image-based subtitles (PGS, VOBSub etc) to text-based subtitles (SRT, mainly). Doing so improves compatibility greatly with a lot of Plex clients and helps to avoid transcoding in a lot of cases. It also enables you to change the size, position, or color of the subtitles on a number of Plex clients. The software used is Subtitle Edit (currently only available for Windows). If you know about similar software for other operating systems, pleas…