Redump Forum — Data inside pregap?

Re: Data inside pregap?

2009-10-20T19:52:33Z

Rocknroms wrote:

And I repeat those sector are not garbage, garbage is something else: wrong offset detection or bytes added by firmware or program, bytes not present on CD.

I've never said those sectors are garbage, I've said that a data track with a glued audio gap on the end has garbage between the descrambled data and audio sectors and even if it were possible to disable descrambling for audio gap when there are data sectors, that gap would be incomplete due to that garbage.

Re: Data inside pregap?

2009-10-20T18:20:21Z

I don't assume anything, I'm complete sure as I recovered those sectors (not my dumps) this way (scrambled and unscrambled) and because those are empty sectors that are always the same in the same position.

And I repeat those sector are not garbage, garbage is something else: wrong offset detection or bytes added by firmware or program, bytes not present on CD.

Your method is only good for converting the random dumps to match our dats

What's the difference if they match? I don't say to do this when you like but after analysing subs... if subs say something, is this wrong now?
I only say: TEST WHAT I SAID instead of assuming it's wrong because you assume wrongly that empty data sectors are something different. If I got 99 matches on 100 this is not assuming, but it's a proof where you have the remaining one (see Sakura Tsushin) as exception. We have a lot of exceptions in DB so please don't tell me that an exception doesn't make a rule because we can close DB as everything could be wrong.

Moreover I never said I want to submit dumps this way, mine was an analisys about something; did you read somewhere I wanted to add discs dumped this way?

I find this solution not only for recovering dumps around but also because as you should remember I have problems dumping Gunbird with cdtoimg

Please, don't ever generate any data, every byte should be read from CD

It's better also not to repeat this everytime you want something to match your thoughs because again we can close DB as everything could be wrong (psx, safedisc, all dvds, 2 tracks discs, etc.).

Re: Data inside pregap?

2009-10-20T17:02:11Z

Rocknroms wrote:

This http://redump.org/disc/8047/ is the only exception, the other one is the same of my examples, that is not garbage unless it has wrong offset.

Wrong, you can't dump WWF by reading the descrambled sectors and rescrambling them - this won't give you the proper image.

Rocknroms wrote:

About the other point you don't fix anything, simply speed up the process importing the same sectors from an empty image without redumping it with cdtoimg or trap disc. There's nothing to fix or modify, disc has always the same structure, if it's mode1 for example, all empty sectors will have the same header at same position for any disc with mode1 form unless toc is fake.

Please, don't ever generate any data, every byte should be read from CD, over. Your method is only good for converting the random dumps to match our dats, but if you're gonna add such semi-generated dumps into db - I'll kill you. You can't say the sector on the particular CD is good and doesn't have any mastering errors without reading it - you can only assume that and assuming is always bad, especially when you claim that the dump comes from the actual CD.

Re: Data inside pregap?

2009-10-20T16:40:10Z

This http://redump.org/disc/8047/ is the only exception, the other one is the same of my examples, that is not garbage unless it has wrong offset.

About the other point you don't fix anything, simply speed up the process importing the same sectors from an empty image without redumping it with cdtoimg or trap disc. There's nothing to fix or modify, disc has always the same structure, if it's mode1 for example, all empty sectors will have the same header at same position for any disc with mode1 form unless toc is fake. The sector I write above is the first empty sector of any image, it's always the same in any disc if this sector is empty. So if you know with sub analisys that n sector or sectors have to be scrambled you can simply take these from an empty image (same position, same format) and unscramble them with descramble_cdda. If they don't have to be scrambled they are simply ready as they are.

PS: About your PCE assertions above, today we have probably something more to check real gaps, I'll report something as soon as I have time to take a look.

Re: Data inside pregap?

2009-10-20T13:29:35Z

Rocknroms wrote:

a) Plextor, cdtoimg and chopfile or b) Swap trick, CD tool and chopfile
Don't you have to rescrambling something in both situations? Or not? don't you have to use descramble_CDDA or something similar?

Nope, no need to use. cdtoimg or swap trick + cd tool give the scrambled sectors, you just dump them and that's all. And I mean cases like http://redump.org/disc/7077/ or http://redump.org/disc/8047/ which contain abnormal scrambled data sectors, which sometimes give correct descrambled ones (by a drive's firmware on some drives). Rescrambling them back won't give you proper sectors. That's why I say, that in any case of incorrect mastering you should dump the scrambled sectors properly, because they can be abnormal.

Rocknroms wrote:

And I repeat again descrambled data can be wrong ok, if so you can use sector from an empty mode1/2 track to fix it (or simply use this track to create scrambled sectors).

We don't fix anything, we preserve the data "as is". Or am I misunderstanding you?

Re: Data inside pregap?

2009-10-20T10:52:03Z

What are you talking about? Did you understand or not?
Empty data sectors has nothing corrupt, they are simply empty with headers

The following is simply an empty mode1 sector and not garbage:

Offset(h) 00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F

00000000  00 FF FF FF FF FF FF FF FF FF FF 00 00 02 00 01  .ÿÿÿÿÿÿÿÿÿÿ.....
00000010  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000020  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000030  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000040  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000050  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000060  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000070  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000080  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000090  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
000000A0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
000000B0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
000000C0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
000000D0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
000000E0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
000000F0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000100  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000110  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000120  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000130  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000140  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000150  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000160  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000170  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000180  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000190  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
000001A0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
000001B0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
000001C0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
000001D0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
000001E0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
000001F0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000200  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000210  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000220  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000230  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000240  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000250  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000260  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000270  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000280  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000290  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
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000002B0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
000002C0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
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000002F0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000300  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
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00000320  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000330  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000340  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000350  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000360  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000370  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000380  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000390  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
000003A0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
000003B0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
000003C0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
000003D0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
000003E0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
000003F0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000400  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000410  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000420  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000430  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000440  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000450  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000460  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000470  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000480  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000490  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
000004A0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
000004B0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
000004C0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
000004D0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
000004E0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
000004F0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000500  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000510  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000520  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000530  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000540  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000550  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000560  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000570  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000580  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000590  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
000005A0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
000005B0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
000005C0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
000005D0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
000005E0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
000005F0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000600  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000610  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000620  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000630  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000640  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000650  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000660  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000670  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000680  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000690  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
000006A0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
000006B0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
000006C0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
000006D0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
000006E0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
000006F0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000700  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000710  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000720  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000730  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000740  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000750  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000760  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000770  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000780  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000790  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
000007A0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
000007B0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
000007C0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
000007D0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
000007E0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
000007F0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000800  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000810  C5 13 68 2B 00 00 00 00 00 00 00 00 00 F7 00 F5  Å.h+.........÷.õ
00000820  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000830  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000840  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000850  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000860  00 00 00 00 00 00 52 35 B8 7D 00 00 00 00 00 00  ......R5¸}......
00000870  00 00 00 F5 00 F4 00 00 00 00 00 00 00 00 00 00  ...õ.ô..........
00000880  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000890  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
000008A0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
000008B0  00 00 00 00 00 00 00 00 00 00 00 00 97 26 D0 56  ............—&ÐV
000008C0  00 00 00 00 00 00 00 00 00 41 00 00 00 00 00 00  .........A......
000008D0  00 00 00 00 00 00 00 00 00 00 00 00 00 00 2D 17  ..............-.
000008E0  2E 1B B1 48 B2 44 00 00 00 00 00 00 00 00 00 00  ..±H²D..........
000008F0  00 00 00 00 00 00 00 65 00 C2 00 E6 00 43 00 00  .......e.Â.æ.C..
00000900  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000910  00 00 45 3C 53 75 33 2B 25 62 00 00 00 00 00 00  ..E

a) Plextor, cdtoimg and chopfile or b) Swap trick, CD tool and chopfile

Don't you have to rescrambling something in both situations? Or not? don't you have to use descramble_CDDA or something similar? I repeat again THOSE SECTORS ARE EMPTY and so they are always the same if they take sector count and mode (the only exception can be fake TOC discs, but I don't see any in DB, did you?).

And I repeat again descrambled data can be wrong ok, if so you can use sector from an empty mode1/2 track to fix it (or simply use this track to create scrambled sectors). And there's no garbage at the end on data track, those are empty dta sectors (you want to call them descrambled audio pregap? Wel is the same thing because this audio is 0x00 and when descrambled you will get empty data sectors like the one above, no garbage this is simply header on 0x00).



Re: Data inside pregap?
2009-10-19T21:34:55Z
No rescrambling of descrambled data, please. We've already seen corrupted scrambled data sectors in the audio gap. Remember, if there are data sectors in audio gap, this is a badly mastered disc and there can be anything, descrambled data can be wrong and rescrambling will make things even worse. We're a database of dumps, not manually rescrambled things. a) Plextor, cdtoimg and chopfile or b) Swap trick, CD tool and chopfile - no more alternatives (yet).


Re: Data inside pregap?
2009-10-19T21:17:51Z
F1ReB4LL wrote:I repeat, any drive descrambles everything in datatrack automatically, including the next audio gap, because it "belongs" to the same datatrack (drive splits tracks by TOC and TOC contains LBAs of all the 01 indexes, 00 index belongs to the previous track, according to this logic), d8 edition of cdtoimg is a must.
I didn's say anything different. We are talking of audio gap and if we have a bad mastering situation (this gap attached to the end of "track 01" has any garbage due to offset correction, the sectors are simply saved as data <---> they are 0x00 audio descrambled to data format so simply empty sectors with mode1/2 headers).
If you have to move sectors as audio, simply use the operation I said above to unscramble sectors (I did this operation to retrieve most of SS dumps if I got right offset correction).


Re: Data inside pregap?
2009-10-19T20:10:05Z
I repeat, any drive descrambles everything in datatrack automatically, including the next audio gap, because it "belongs" to the same datatrack (drive splits tracks by TOC and TOC contains LBAs of all the 01 indexes, 00 index belongs to the previous track, according to this logic), d8 edition of cdtoimg is a must.


Re: Data inside pregap?
2009-10-19T17:13:14Z
F1ReB4LL wrote:Rocknroms wrote:F1ReB4LL, if it's confirmed that there are data sectors in pregap we can simply take them from Isobuster dumping the data track as always and then use remove instead of resize:
Any drive manages the 1st gap as a part of data track, if there are any scrambled sectors - they will be descrambled. Also don't forget, that you can't get a complete gap in isobuster dump of the first track - with positive combined offset there's always a garbage between the data and audio sectors and, as a result, the very end of the gap is cut.
If you save track or segment with isobuster (or if you take it from bin-cue) there's no garbage inside pregap. Garbage is only present in sector view on real CD (or you can get it with wrong offset dumping audio), it is not dumped otherwise you'll have to move also data offset like we do with audio.
It could be that IB put garbage in pregap of track02 (dumping track01) simply because it cannot handle well scrambled sectors, otherwise for example every SS disc with data+data would be wrong (I always got same result perfectrip=isobuster after moving sectors and they are all disc with positive offset).
By the way my point is always valid, you can use also my tools used to fix DC pregaps, simply find sector count, save and unscramble (all those sectors we are talking about are simply empty data sector with data only headers and thse are always the same if you get the correct data mode).
Moreover you can get all pregap in data mode in IB, sector count it's not cut as it is between low and high density on GDIs.


Re: Data inside pregap?
2009-10-19T16:10:25Z
Rocknroms wrote:F1ReB4LL, if it's confirmed that there are data sectors in pregap we can simply take them from Isobuster dumping the data track as always and then use remove instead of resize:
Any drive manages the 1st gap as a part of data track, if there are any scrambled sectors - they will be descrambled. Also don't forget, that you can't get a complete gap in isobuster dump of the first track - with positive combined offset there's always a garbage between the data and audio sectors and, as a result, the very end of the gap is cut.
Feltzkrone wrote:By the way, what happens if there is a pregap of 03.00 of which the first 01.00 are data sectors (even the Q subchannel denotes this) and the remaining 02.00 are audio sectors (Q subchannel denotes this clearly, too). Probably those data sectors have to be moved to the binary file for Track 2, but as ssjkakaroto asks, too, don't they have to be scrambled then? 
And whatever the right choice on this question is: How can we represent the sector mode switch at relative -02.00 in Q subchannel with CUE sheet syntax properly? At least I don't find a way to do this. Isn't it that when CUE sheet denotes Audio sectors the subchannel will be (re)generated accordingly, i.e. the 75 data sectors in Track 2 will be marked with Q-CONTROL 0 (Audio) instead of 4 (Data)? So how can the CD properly be preserved using CUE/BIN then?
In my opinion, we shouldn't have any descrambled images at all - a dump should represent the unmodified content of the disc. Descrambling gives us lots of problems. Yes, there are images with the data sectors in audio - some of them have those sectors marked as data in the subs (TFX, Base Jumpers, etc.), others - don't (many Saturn ones, like Gunbird; some PC ones, like that Twinsen's Odyssey). I've wanted to split them somehow, that's why in the first case data sectors are descrambled and in the second they are left scrambled. If we want proper dumps, both should be left unscrambled (along with the data tracks) and the subs should be also preserved.
Feltzkrone wrote:In subchannel data unluckily there is no error correction involved as far as I know, most drives drop in random errors occassionally when reading subchannel data. Additionally the drive used should be of higher quality. So I guess we would need a utility to read out the subs which re-reads sectors which gave suspicious results (CloneCD doesn't compensate those random errors).
First of all, the database can't currently handle them at all -- CDs with different rings and same tracks usually have different subs, so they should be assignable to a ringcode, not to an entry. As for the actual dumping -- yes, subs should be dumped either via multiple rereadings (prepare to wait ~8-12 hours per CD) or cleaned manually or automatically (this can easily ruin any protection).


Re: Data inside pregap?
2009-10-19T06:38:57Z
ssjkakaroto wrote:The way I see it, for full preservation, in this cases, we'll need to store the subchannel file with the dump information. Luckily, 7zipped compressed subchannel info can be less than 1 MB.
In subchannel data unluckily there is no error correction involved as far as I know, most drives drop in random errors occassionally when reading subchannel data. Additionally the drive used should be of higher quality. So I guess we would need a utility to read out the subs which re-reads sectors which gave suspicious results (CloneCD doesn't compensate those random errors). Does such a utility exist? Even better: Something like ECM for subchannel data could be useful, I guess this would take a .sub file's size down to some KB if the subchannel data is made up according to the normal rules.

Rocknroms wrote:Moreover redump is not a DB for burning/pirating/etc., but for preserving data.
Well, if data is preserved in CUE/BIN format only some data (like I described, in thise case) is actually lost. According to the CUE file the data sectors are told to be audio data and will be handled like audio data by all applications, regardless of mounting, burning etc. Moreover who wants do prohibit someone making a copy of a self-bought unprotected CD? In this case reading out the original CD according to redump.org guide, then burning the resulting image would not bet sufficient in means of preservation.


Re: Data inside pregap?
2009-10-18T23:50:45Z
@Rocknroms: The whole 3 seconds of the pregap are scrambled data sectors.
The way I see it, for full preservation, in this cases, we'll need to store the subchannel file with the dump information. Luckily, 7zipped compressed subchannel info can be less than 1 MB.


Re: Data inside pregap?
2009-10-18T21:05:41Z
Feltzkrone wrote:And whatever the right choice on this question is: How can we represent the sector mode switch at relative -02.00 in Q subchannel with CUE sheet syntax properly? At least I don't find a way to do this. Isn't it that when CUE sheet denotes Audio sectors the subchannel will be (re)generated accordingly, i.e. the 75 data sectors in Track 2 will be marked with Q-CONTROL 0 (Audio) instead of 4 (Data)? So how can the CD properly be preserved using CUE/BIN then?
You cannot represent sectors i CUE correctly at all. This matter was discussed in the past with Fireball, I had the same thoughts of yours but then I change my mind because we cannot fix arbitrary something reported in subcode unless we have a clear reply from someone who mastered those discs. To explain better, if those discs were badly mastered (as it is) we cannot fix them otherwise we have no real preservetion. Eventually it could be discussed again once we have more hints.
Moreover redump is not a DB for burning/pirating/etc., but for preserving data. Those sectors can be switched in any moment, at least we have preserved all data like reported in subcodes.
It would be nice if a guide for exactly that situation (pregap consists of both data and audio sectors) with explanation of technical background could be added somewhere by a person who really understands it.
I'm working on something also because we have no scambling/descrambling faq unless themabus faq on pce discs.
ssjkakaroto wrote:@whoever added my dump: I think you should leave the comment about the scrambled data in the track 2 pregap.
Can you repost comment you add about un/scrambled sector (I dont understand if is one sector or one second) and someone will add it back.
EDIT: I have to understand too why someone removes comments in PC section when they are necessary. I have already asked it in the past...


Re: Data inside pregap?
2009-10-18T20:08:28Z
@whoever added my dump: I think you should leave the comment about the scrambled data in the track 2 pregap.