That's right, thanks. But the point is I can identify them because they aren't really the same source, not necessarily because one has higher bit depth than the other.
I have the Doors DVDA box set, do you know how that varies from the current redbooks? It would make for a decent comparison.
On the Metallica DVDA all I can hear is how they fucked up nearly everything about that album that Metallica didn't fuck up when they recorded it, so after hearing it twice I have stuck with redbook.