Discs with non-compliant sector in the end that have to be descrambled

[user7]

Pardon the verbose title. I want a dedicated topic to this discussion so it doesn't become an obscured nuance that need-be tracked across several random threads.

Required reading: https://github.com/saramibreak/DiscImag … issues/250

All known examples (all of which are correctly dumped in redump by the redumper app):
-"CD-i / Video CD Titel-Neuheiten II/95", see further convo: /viewtopic.php?t=47291 … iten-ii95/
-all 7th Guests Philips CDi's (doesn't include Disc 2 Audio CD of course) - https://redump.info/discs/quicksearch/7th … rt/system/

[sadikyo]

Additionally, I'll add that really any CD-i discs should be currently dumped by redumper as the strongly preferred program for redump purposes. 

Perhaps a notation or comment of some sort may be helpful on these particular affected discs, but I don't know or have a strong opinion there.

[sarami]

I asked a similar issue to F1ReB4LL in the past.

Some PC Engine CD have 00:02:74 pregap in track 02 (e.g. https://redump.info/disc/40354/).
These 1st 75 pregaps have "audio" flag in sub Qchannel.

Code: Select all

LBA[003434, 0x00d6a]: P[ff], Q[01020000020500004759a14d]{Audio, 2ch, Copy NG, Pre-emphasis No, Track[02], Idx[00], RMSF[00:02:05], AMSF[00:47:59]}, RtoW[0, 0, 0, 0]
LBA[003435, 0x00d6b]: P[ff], Q[01020000020400004760ac66]{Audio, 2ch, Copy NG, Pre-emphasis No, Track[02], Idx[00], RMSF[00:02:04], AMSF[00:47:60]}, RtoW[0, 0, 0, 0]
LBA[003436, 0x00d6c]: P[ff], Q[01020000020300004761db93]{Audio, 2ch, Copy NG, Pre-emphasis No, Track[02], Idx[00], RMSF[00:02:03], AMSF[00:47:61]}, RtoW[0, 0, 0, 0]
LBA[003437, 0x00d6d]: P[ff], Q[0102000002020000476241a1]{Audio, 2ch, Copy NG, Pre-emphasis No, Track[02], Idx[00], RMSF[00:02:02], AMSF[00:47:62]}, RtoW[0, 0, 0, 0]
LBA[003438, 0x00d6e]: P[ff], Q[01020000020100004763bf52]{Audio, 2ch, Copy NG, Pre-emphasis No, Track[02], Idx[00], RMSF[00:02:01], AMSF[00:47:63]}, RtoW[0, 0, 0, 0]
LBA[003439, 0x00d6f]: P[ff], Q[0102000002000000476465e4]{Audio, 2ch, Copy NG, Pre-emphasis No, Track[02], Idx[00], RMSF[00:02:00], AMSF[00:47:64]}, RtoW[0, 0, 0, 0]
LBA[003440, 0x00d70]: P[ff], Q[010200000174000047652fa5]{Audio, 2ch, Copy NG, Pre-emphasis No, Track[02], Idx[00], RMSF[00:01:74], AMSF[00:47:65]}, RtoW[0, 0, 0, 0]
LBA[003441, 0x00d71]: P[ff], Q[410200000173000047660a08]{ Data,      Copy NG,                  Track[02], Idx[00], RMSF[00:01:73], AMSF[00:47:66]}, RtoW[0, 0, 0, 0]
LBA[003442, 0x00d72]: P[ff], Q[41020000017200004767b078]{ Data,      Copy NG,                  Track[02], Idx[00], RMSF[00:01:72], AMSF[00:47:67]}, RtoW[0, 0, 0, 0]
LBA[003443, 0x00d73]: P[ff], Q[41020000017100004768af45]{ Data,      Copy NG,                  Track[02], Idx[00], RMSF[00:01:71], AMSF[00:47:68]}, RtoW[0, 0, 0, 0]
LBA[003444, 0x00d74]: P[ff], Q[410200000170000047691535]{ Data,      Copy NG,                  Track[02], Idx[00], RMSF[00:01:70], AMSF[00:47:69]}, RtoW[0, 0, 0, 0]
LBA[003445, 0x00d75]: P[ff], Q[410200000169000047703a0b]{ Data,      Copy NG,                  Track[02], Idx[00], RMSF[00:01:69], AMSF[00:47:70]}, RtoW[0, 0, 0, 0]

These "audio" sectors should not be descrambled? LBA 3440 have sync, msf and mode, but it's audio in sub Q.

If to follow the red/yellow book standard, the first second (75 sectors) has the same mode as the previous track, should be left scrambled, the rest of pregap (150 sectors) - descrambled. But due to some kind of a mastering error the first second is 74 sectors, not 75, I guess? So the 74 sectors should be left as is and the next 150 sectors descrambled, I think.
If to follow the TOC logic (next track starts at index 01 and index 00 belongs to the previous track) - the entire pregap should be left scrambled.
If to follow the sub logic (next track starts at index 00) - all the pregap sectors should be descrambled if possible.

So, probably it is better to descramble those.

The above case is that track 1 is audio, track 2 is data. But in case of "CD-i / Video CD Titel-Neuheiten II/95", track 1 is data, track 2 is audio.
Then, if to follow the red/yellow book standard, the first second (75 sectors) has the same mode as the previous track, should be descrambled, the rest of pregap (150 sectors) - left scrambled.
If to follow the TOC logic (next track starts at index 01 and index 00 belongs to the previous track) - the entire pregap should be descrambled.
If to follow the sub logic (next track starts at index 00) - all the pregap sectors should be left scrambled if possible.

So, probably it is better to left scrambled those.