IIRC, it's actually debatable if the pre-emphasis flag is supposed to be set. I don't remember the exact details anymore, but I think it was discovered that there multiple releases with bit-identical audio tracks, but some of them have the flag set while others don't. They can't both be correct, because the audio data should've changed if the emphasis was removed.

▲

Lammy 3 hours ago | parent [-]

Make sure that it isn't a case of the software you're using to inspect the disc intentionally looking the other way with regard to that flag.

> Quake has the pre-emphasis metadata flagged in the subcodes but not flagged in the TOC, so some software players/rippers like (annoyingly) Exact Audio Copy won't heed it

I learned that this is an intentional deficiency in EAC: https://forums.stevehoffman.tv/threads/eac-not-detecting-pre...

> For a short while, up to version 0.95b3 [in 2004], Exact Audio Copy had a manual function to actually scan the audio area of the disc also [talking about subcode channel Q versus the TOC] to find if tracks used pre-emphasis. This was removed due to some perceived legal threat. Now, basically, a standards-compliant disc that doesn't use the TOC kludge won't show "pre-emphasis"

And sure enough, the Red Book standard mentions usage of the other three flag bits alongside the pre-emphasis flag: https://audio-union.com/wp-content/uploads/2023/02/Red-Book-...

The adjacent bit is “copy prohibited” versus “copy permitted”, which is not a piece of metadata I knew Compact Disc had. Makes a lot more sense why EAC would remove that feature in the legal climate of the P2P era, because to look for one flag also must look for the other, and this way it's out of sight and out of mind and Gee Your Honor We Didn't Know You Couldn't Do That if someone uses EAC to rip a “copy prohibited” disc. I wish I could get this feature back in 2026 though :p

▲

protimewaster 2 hours ago | parent [-]

I actually remembered more about this after my initial post. I ended up with two copies of Quake (one is the original shareware release and one is a later release of the full game), and one of them has the PRE flag set in the TOC and the other one doesn't. Now I'm wondering if I ever checked the subcodes for the one that's missing the flags in the TOC. I'll have to dig it out sometime and check.

I did verify that the audio is identical down to an offset, though, between the two.

> The adjacent bit is “copy prohibited” versus “copy permitted”, which is not a piece of metadata I knew Compact Disc had.

I wonder if any equipment ever actually used those other flags for anything?

	▲	Sesse__ 5 minutes ago \| parent [-]
		> I wonder if any equipment ever actually used those other flags for anything? MiniDisc did. You could make one (digital) copy but not two.