@paradoxical: at least the latest ffmpeg compiled with libbluray can't extract pgs subtitles here,... (there's also an entry about it in the bug tracker: https://ffmpeg.org/trac/ffmpeg/ticket/2208)
-> How do you extract pgs subtitles with ffmpeg? (most of the time I can use tsMuxeR as alternative, but whenever the current mpls consists of too many m2ts files, tsMuxeR always creates to large output file names
)