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Re: Sub-channel support for CDs [Re: xinyingho] #106336
07/03/16 10:16 PM
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Originally Posted By xinyingho
I read this on other forums. For instance, at this thread at the AssemblerGames. I myself didn't do any testing so I'm just following what's being said.

Yes and this thread describes the wobble only on the pre-ring area, but not the "pre-groove" area used for ATIP and PS1 protection. So the Saturn is on its own (probably, together with Dreamcast, whose discs have similar rings).

Re: Sub-channel support for CDs [Re: Fake Shemp] #106337
07/03/16 10:30 PM
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Yes, perhaps I've read this a bit too fast.

Those guys didn't determine that Saturn games have a pre-groove area holding informations but just that they have a pre-ring area that wobbles more than necessary, nothing conclusive about holding informations or not.
But this pre-ring area is probably what hints a Saturn drive that there is a logo ring.

Re: Sub-channel support for CDs [Re: Fake Shemp] #106354
07/04/16 07:56 PM
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Originally Posted By R. Belmont
Originally Posted By Just Desserts
Unless you're planning on doing this all yourself within a non-glacial time frame, or you already have people waiting to start implementing it, it would be real great if you would stop using definitive terms like "will" when referring to future features.

We have a thread here full of people who are willing to admit in public that They Care Very Very Much about this stuff, so I figure it's also our best odds of recruiting some people who have the ISO standards as light bedtime reading and could actually pull it off.

And I'm comfortable using "will" because on a long enough time scale, representing CDs the way I want will become the only obvious way to do it.

LN: I'm very serious about the comparison to floppies. We can convert existing formats to a raw pits-and-lands bitstream, and even if it isn't immediately possible to actually read in that format it doesn't mean we have to compromise our internal representation. The mistake I made implementing CDs the first time is that the representation was just what the Konami games needed, and other shit got tacked on. The second time, it must be done right.

Hi! I care very much about this stuff. wink

As I said in my first post, I am willing to work on this myself, I'm not trying to force mamedev to do anything. Granted, I am quite the shite coder and not too familiar with neither the rainbow books nor MAME internals, so of course it would be on glacial time. wink

Personally, I absolutely agree with the parallel to the new floppy system. We have dumps of CDs in a helluva lot of formats already. Going really low level with the internal representation will at least allow for any current format to be represented. Pits-and-lands bitstream just seem like a good idea.

Re: Sub-channel support for CDs [Re: Fake Shemp] #106358
07/05/16 03:33 PM
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Originally Posted By Fake Shemp
Going really low level with the internal representation will at least allow for any current format to be represented. Pits-and-lands bitstream just seem like a good idea.

Now the only problem is to get a few complete rawstream dumps to figure out the true CD format smile Exact lead-in/lead-out size, possible pre-lead-in data, etc.

Re: Sub-channel support for CDs [Re: Fake Shemp] #106408
07/06/16 10:29 PM
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LOL for this, we'll need to raid a CD factory and steal some CD masters and other hardware. Or maybe we can find a mastering engineer that is willing to help us and lend some stuff from his/her work smile

Re: Sub-channel support for CDs [Re: Fake Shemp] #106469
07/10/16 05:47 PM
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How will CD masters help? Reading the pits and lands from a glass master would be harder than reading them from a CD.

FWIW plenty of drives have MCU's with flash memory. Poking around with those would probably be your first call.


Last edited by smf; 07/10/16 05:49 PM.
Re: Sub-channel support for CDs [Re: Fake Shemp] #106472
07/10/16 07:04 PM
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Re: Sub-channel support for CDs [Re: smf] #106473
07/10/16 08:18 PM
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somewhere else entirely
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somewhere else entirely
Originally Posted By smf
FWIW plenty of drives have MCU's with flash memory. Poking around with those would probably be your first call.


You mean, like, I don't know, the LG GP40NW10?

Re: Sub-channel support for CDs [Re: smf] #106474
07/10/16 09:03 PM
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Originally Posted By smf
FWIW plenty of drives have MCU's with flash memory. Poking around with those would probably be your first call.


Firmware flash chip, you mean? Modifying the firmware isn't an easy task.

Some drives also allow to get more data than you should be able to via the cache reading commands, but, AFAIK, these are only helpful to get the raw DVD sectors (2064 bytes per sector and beyond).

Re: Sub-channel support for CDs [Re: F1ReB4LL] #106475
07/10/16 10:48 PM
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Originally Posted By F1ReB4LL
Firmware flash chip, you mean? Modifying the firmware isn't an easy task.


If you're looking for an easy task then you're very much in the wrong place.

Originally Posted By Olivier Galibert
You mean, like, I don't know, the LG GP40NW10?


Ding ding ding, we have a winner.

Last edited by smf; 07/10/16 10:49 PM.
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