I’m not very technical on issues like this mate (so hopefully someone else with far better knowledge than me will along to help you), though…

I find videohelp.com a big help for this type of thing mate - years ago they were a very useful resource for many of the laserdisc-based rips of the OT on here 😃

https://forum.videohelp.com/forums/47-Blu-ray-Ripping

https://www.videohelp.com/software/DVD-Audio-Extractor (it says for dvd - but should work for blu ray)

Handbrake is a free and simple to use program for ripping too - you can convert the file to mp3 quite easily 😃

More info here - http://www.techradar.com/news/the-best-free-dvd-ripper

Handbrake - https://handbrake.fr/downloads.php

Good luck with it mate 😃