SpritesMind.Net

Pretty cool that people have managed to burn those rings back and make the visible text readable. I wonder how many coasters the guys at Sega made when they were trying to pull that off?

I was speaking about the reason for storing them scrambled in a cd image file, which I thought was what byuu was asking about, but I can now see he did say "on disk", so yes, you're right, scrambling is done edfectively to increase the reliability of error correction, although my understanding is it...

I'm currently working on understanding the information that's in the patents, specifically US4325121 . A lot of important information is contained in the microword descriptions in Appendix H, but they're borderline illegible, and very difficult to work with in their current form, so I'm doing a full...

Tool generated would certainly explain why it's so incomprehensible, thanks for taking a look.

I'm not opposed to splitting the subcode data, but my question is then, where do we stop? Should we split data sectors' 304 bytes of extra data to take 2352-byte sectors to 2048-byte sectors, and then have a separate .ecc file? They would probably compress better without the error correction data. ...

If you can get three or more rips of each disk (preferably more like five or six), you can reconcile these errors and cancel them out, to get a true image of the disk as it really is, apart from surface damage or smudges on the disk surface that are interfering that is. If you can get three or more...

What Eke says is true, and no existing games rely on subcode data, but if you want to emulate/preserve the hardware itself rather than just the games, and if you want to support homebrew, all the subcode data is made available to programs running on the system, and should be properly supported for c...

Well, you know me (probably, anyway.) I've already dealt with this and the unacceptable way Famicom Disk Images are currently stored, I'll handle this the same way. I'll support a new image format that contains all data: lead-in, pregap, postgap, lead-out, subchannel data, etc in scrambled form. Un...

You are correct that TOC is stored in q-channel within the lead-in. Pretty sure the cd ripper programs that extract subchannel data don't even include this, but that info is stored in the cue file to be recreated. So then as I presume the Mega CD BIOS expects to be able to read the raw TOC data, it...

Does anyone here know how to get in touch with Olivier Galibert? I've found he's put together... something at https://github.com/galibert/m68ksim , but there's no comments, no readme, no documentation of any kind, and apparently no reference to it anywhere on the internet. There's also a bit of a fo...

I'll add that you're right though, the lead-in and lead-out areas "degenerate" towards the edges, as the laser power level drops from the writing process. For the MegaLD images, I'm reconstructing the full data to the edges from the known data before it starts fading.

The next level down from this that I consider "valid" is to store data with the frames decoded and PQ error correction already performed, but with mode 1 sectors still scrambled and ECC/EDC correction not yet applied, and the subchannel data retained. All that you've done here is to decode the fram...

I'm gonna laugh if we end up redumping every single CD from scratch using a Mega CD/LD simply because it's capable of dumping all that. It's probably going to happen actually. The work that's been done with the Domesday Duplicator ( https://www.domesday86.com/?page_id=978 ) I expect will probably p...

Speaking of, where exactly is the TOC? If my reading up on CD formats is correct, is this part of the ~150-sector lead-in, repeated throughout it, and something that needs to be recreated from the CUE file? (well, not that we'd have to create the exact bits on the disc, just return the correct info...

I've flirted with the idea of doing this on and off for years now, but this evening I've decided I'm going to focus on a microcode-level 68000 emulation core, and I'm going to continue with it until it's a reality. The sheer amount of data and work involved in this space feels a bit overwhelming rig...