This isn’t strictly speaking an IFS development question, but I know all
the right people hang out here.
I’m looking at some CDs that have mode 2 content. These are enhanced
CDs in the blue book sense. Most of the files are recorded as Mode 2,
Form1 which gives 2048 byte sectors and all the standard CD error
correction. However a few files are recorded as Mode 2, Form 2. This
reduces the error correction and accoring to the spec I have the 2352
bytes of uncorrected data is broken up as follows:
bytes description
12 sync
4 header
8 subheader
2324 user data
4 EDC
However when I look at files that have been read by either Win XP, 2000,
or 98 the files don’t seem to have come off like that.
Firstly, CDFS pre-pends a fixed RIFF header to the file. This is
presumably on the assumption that these files are always the pictures
files, so they ought to have one.
Secondly, when I look at the data in the files I can see the subheader
bytes repeating every 2352 bytes. Now I don’t think that it should be
in the file at all, and certainly I have nothing that’ll understand the
files, however whatever data there is should be stored in 2324 byte groups.
Has anyone else looked at this? I know it’s a bit obscure…
Thanks
Andy.