Open HDMV PGS subtitles in GNU/Linux

I wanted to know if there's any software in GNU/Linux which can read BluRay subtitles (HDMV PGS). I'm not talking about making an OCR to convert them to SRT like everyone asks, but just reading them to see the timing of each line, and open the image representing the writings in each line. I want to read their content without having to play the whole film, I don't care about being able to edit the lines or converting the subtitle in any other format. According to mkvextract the extension should be .sup, but when extracting some HDMV PGS subtitles with that extension, neither GNOME Subtitles Edit nor Gaupol seem able to read it. Does anyone know of any software which is able to read them?