Batch tool creates SRT file only useable on Andriod TV

Hey all, searched for a bit on this topic, but I couldn’t find an answer as it seems to be fairly niche.

I have a few shows/series on my Jellyfin server that have embedded ASS subtitle files within the MKV video files. With the embedded ASS sub files, playing the files on my Android TV via the Jellyfin app would lag due to the ASS sub files, and trying to play the videos on the Swiftfin iOS app wouldn’t work at all. I narrowed down the problem to the ASS sub files being present, and needed a way to extract and convert them to SRT files. Enter MKVToolNix and MKVToolNix Batch.

Running the video files through MKVToolNix Batch (mostly) successfully extracted and converted the sub files to SRT. When I play the video files on my Android TV I can just select the SRT files with no issue and it’s the correct font size and doesn’t lag anymore. However, when I try to play the same video file on the native Jellyfin Windows app, the subtitles are so large they literally take up the entire screen and obscure the video itself. I have double, triple, and quadruple checked my subtitle settings are correctly set up within Jellyfin; it’s only these converted files that are displaying extremely large text. The Swiftfin iOS app doesn’t recognize the new SRT files at all, though I suspect that’s a Swiftfin specific issue and isn’t really something I expect help with.

Does anyone know a way to make sure that the extracted SRT files get extracted in a way that matches the format/styling of the original ASS files?

Screenshot to show the size of the new SRT text: upload://ay0KkkeyBfqC1lA1DE9tcdXUOdz.jpeg

Thanks in advance!

The SRT subtitle format lacks most of the features that work in SSA/ASS. For example, there are no provisions for controlling font sizes. As far as I know the only styling controls are bold, italic, underline & font colors. Everything else is up to the player.