Author Topic: Help with Dreamcast  (Read 2215 times)

Offline IlDucci

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Help with Dreamcast
« on: May 02, 2014, 11:06:11 PM »
Hi there, noob here.

I was dumping my copy of What's Shenmue via SD when I realized the .md5s are wrong. So I redumped again and then thought that there was a code on the TOSEC dat file. Where can I find the fourth value? Mine seems to be different in the inner circle of the disc.

Thank you for your time.



Offline Cassiel

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Re: Help with Dreamcast
« Reply #1 on: May 06, 2014, 10:32:49 AM »
Cross post here: http://dcemulation.org/dumpcast/viewtopic.php?f=2&t=1743

The boys over at Dumpcast (who do all our Dreamcast/NOAMI dumping) will know more.  :)

Offline IlDucci

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Re: Help with Dreamcast
« Reply #2 on: May 06, 2014, 12:31:49 PM »
Thanks. I'll register there so I get notified when an answer shows up...
« Last Edit: May 06, 2014, 05:16:22 PM by IlDucci »

Offline darcagn

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Re: Help with Dreamcast
« Reply #3 on: May 09, 2014, 12:16:49 AM »
Hi, there, this is a crosspost here/Dumpcast/Assembler, haha.

Hopefully I can clear this up for you without creating more confusion...

The ringcode is a code that can basically be used to identify if the discs are from the same batch (when manufacturing/pressing). If two discs have the same ringcode, they are from the same batch; if they have different ringcodes, they are from different batches.

For data tracks, the MD5 should be the same across all batches. If the MD5 is not the same, then that means we have a different version of the game -- perhaps bugs were patched, or something new was added. This is uncommon with Dreamcast titles (In the USA, for example, I think only Midway titles, like Ready 2 Rumble Boxing, Hydro Thunder, etc. had multiple public builds).

For audio tracks, the MD5 may or may not be the same across all batches, even if the source audio track is the same exact audio. This is because during the manufacturing process, bytes are added to the beginning of the audio tracks, and a different amount is done depending on the factory/batch. This is called the "audio offset." Audio tracks from the same batch/ringcode should all have matching MD5s, but audio tracks from different batches/ringcodes may or may not have different MD5s.

Discs with different audio tracks but the same data tracks are called "ringcode variants" because the contents are practically the same, but bit-by-bit they are technically not. They are always less of a priority to dump because they are not truly unique.

Luckily, all PAL titles have the same offset, so there's no ringcode variants for PAL titles making a 100% complete PAL set pretty obtainable! For NTSC-U and NTSC-J, there are some titles with a dozen or more ringcodes, so we haven't gotten around to dumping all of them just yet--if ever!

So, back to your original question, which tracks do not have matching MD5 sums? The audio tracks, or the data tracks? At the moment, we are aware of at least one What's Shenmue? ringcode variant, but we only have one dump of it, so it's considered unverified and thus not in our public dat files. So if you wouldn't mind, we'd appreciate you posting the MD5s for your disc in that thread and you could possibly help us verify another variant!

Also, I'm looking forward to the What's Shenmue translation!

Offline Cassiel

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Re: Help with Dreamcast
« Reply #4 on: May 09, 2014, 11:04:08 AM »
That is a brilliant write up darcagn... thanks for the info!

Offline IlDucci

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Re: Help with Dreamcast
« Reply #5 on: May 09, 2014, 02:21:02 PM »
You dedicated some time to answer in full detail, so I guess I'll have to reply everywhere: After checking MD5s and such it seems that only the audio tracks change. The data tracks are exactly the same.

INFO:
SEGA SEGAKATANA
SEGA ENTERPRISES
D690 GD-ROM1/1
J 0799010
6107179 V1.004
19990720
1ST_READ.BIN
SEGA ENTERPRISES
WHATS SHENMUE

GDI FILE:
9
1 0 4 2352 track01.bin 0
2 600 0 2352 track02.raw 0
3 45000 4 2352 track03.bin 0
4 358492 0 2352 track04.raw 0
5 359081 0 2352 track05.raw 0
6 370791 0 2352 track06.raw 0
7 380787 0 2352 track07.raw 0
8 388253 0 2352 track08.raw 0
9 389344 4 2352 track09.bin 0

CRC-32:
track03.bin cd135ffd
track04.raw 3f1592f2
track05.raw 9c97ad60
track06.raw d7893dc7
track07.raw 39e2a81e
track08.raw 1ed5c3c0
track09.bin 8468eadc
track01.bin a0a8594e
track02.raw 0de03f29

MD5:
6f5441137379f0b4f2aa582ba5c1ed23 *track04.raw
d84891aa4bf130ed049fa631ea849bf6 *track05.raw
7542a63d468a446c74ae4f283e9925a6 *track06.raw
8945ee4a8f2ce16bd33b3b9b198c0206 *track07.raw
0107eed43958e627f78f1fe720eafcfd *track08.raw
ab7c43fb628f9f77c46bce05a27e2a46 *track09.bin
0885c04b770af89826d72c8418afef88 *track01.bin
d09be539a7074a058159505b7f5fdcb3 *track02.raw
8171f4ebf9711cb7a692c630ef56e23b *track03.bin

SHA-1:
324a506197623c29bcd7d468bb4eb97d575ba321 *track06.raw
193872e0ffc3ed1e3df690777394e0fdcb45126b *track07.raw
c04bae30247250f7a9e99384d3b2c48a7529b9d1 *track08.raw
82071f7ac4a2a9c05ae7b144b7314a0689fee889 *track09.bin
d1edcea373c3a939a802c7e5154e6d74277b7930 *track01.bin
db680939aae4bf61d0e588414c72a47c6dd92cdd *track02.raw
15205fb89746214209c82e275a051270471587a8 *track03.bin
ebfa52b7038846e5a2522014e29cd9c4ce23c42f *track04.raw
d126db86c9ac110c90413b5d10171d6f8da1f0d3 *track05.raw