[FFmpeg-user] DVD EIA-608 to ASS from stdin with custom style

[CGar]

When extracting EIA-608 captions from a DVD to an ASS file I am
unsure how to  specify the style. I've seen snippets online about a
force_style option but it seems to be about hardcoding them or
specifying a subtitle file as input. Since I'm reading from stdin I'm
unsure where or how to write the relevant part.

My command line is as follows:
[...] | ffmpeg -f lavfi -i 'movie=pipe\\:0[out0+subcc]' -map s sub_out.ass

Where or how would I add something like:
force_style=BorderStyle=1,Outline=2

-- 
-CGar-