Enhanced CDs: patterns in leadout

Hello all.

I happen to have 4 Enhanced CDs and a reader that helped me get into their leadouts, where I found special patterns…

Disc A: 45AAD10000000255331852DC
Disc B: 45AAD1000000026721374985
Disc C: 45AAD10000000274015739F6
Disc D: 45AAD10000000274393289C9

The pattern occupies 3 adjacent subcode blocks of every 6, where the rest are regular subcode blocks, just as the figure shows…
does anybody know about this patterns? Thanks beforehand for sharing your knowledge.

Hi bud,

What you see are mode 5 Q codes. These are part of the Orange book. You will see mode 5 pointers in the leadin of these multisession CDs as well.

The ones in leadout that you show are the D1 points. I think these are only in the 2nd and higher session. They follow the same rules as the mode 5 pointers in leadin and must be in that repeating pattern (3 mode 1, 3 mode 5). The PMIN, PSEC and PFRAME of the D1 point gives the start time of the first track in this session. In your example your ROM data track started at 55:33:18.

Does this help?


Hello Rich.

I think you’re right about POINT=D1h being not present in the first session, I confirmed it with the 4 discs.

They follow the same rules as the mode 5 pointers in leadin
I attach Q Sub-channel Mode-5 Format recorded in Lead-in from MMC-2 so all can see mentioned rules. Of course it has been helpful Rich, thanks a lot.