www.makemkv.com

Using 1.6.1 I've noticed (good) behavior I have not seen before.

Closed captions are rare in Blu-ray but they do exist. They show up in MakeMKV for DVD but not Blu-ray. But: an MKV I just produced from a Blu-ray has the cc text as an extra track, for free.

I've only tried this on one disk but will test more, time permitting.

From my notes, here is a list of Blu-rays with closed captions.

Bridge Too Far, A (1977)
Die Another Day (2002)
Entrapment (1999)
Firefly (2002)
I, Robot (2004)
Master and Commander (2003)
Mr & Mrs Smith (2005)
Omen, The (1976) (old disk)
Omen III: The Final Conflict (1981) (old disk)

I've become aware of them because the OPPO 203 detects and decodes closed captions on both DVD and Blu-ray, a rare feature since HDMI came in.

If a disk has been issued in multiple editions the captioning may not be present in later versions.

I'm using Linux; I don't know if the cc detection is different between platforms.