Looking for volunteers! Help us help the community!

Place for discussing homebrew games, development, new releases and emulation.

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mrneo240
stalker
Posts: 285

Looking for volunteers! Help us help the community!

Post#1 » Fri Nov 03, 2017 2:51 pm

Hello,

If you don't want to read then SKIP to the end, if you want to know about the project read on:

So we started a new project in order to help ease the issue of playing CDDA from WinCE games. It's a piece of Homebrew that reads a disc inserted into the Dreamcast and outputs the track information. I believe this is what is preventing CD-Rs from playing certain music correctly. Lots of technical stuff But it boils down to the Dreamcast reading a discs TOC 2 ways and I don't believe you can easily get access to the second way (the way the bios works, probably can with syscalls but I haven't dug). Original gd-rom of retail discs have their TOC info correct in every sense of the word.

CDDA can be played a couple of ways in WinCE, notably by track or sector and then can be paused and resumed certain ways as well. The laser can only be in one place at a time and it's either reading game data or playing music. Looking through the SDK docs and compiling information and comparing how games actually "play" music I believe it can be fixed with some minor changes to IP.bin and possibly patching the executable. This would be groundbreaking new stuff for the community and fix many issues currently present in WinCE games.

I spent a couple hours last night around 2am working on this program to dump specific info from discs from within WinCE. I could burn it to a CD but I only own 3 actual retail discs (none of which are useful in regards to this tool) and as far as I can tell it doesn't work with burned games and I got too tired to continue.


Project needs:

  • volunteers
    • Have a gdrom emulator or willing to burn a disc (possibly wasting it)
    • If having a gdrom emulator then be willing to download gdis of wince games that have cdda
    • If burning disc then have retail discs of the same games
  • People who have experimented with this before at any skill level
  • People comfortable in reversing/assembly

Here's a link to the tool:
https://mega.nz/#!ZllmEIxT!X4Q_FxmHJ52X ... edASnyw1uw

If you are just curious or feeling like seeing what this is about burn it but don't expect anything interesting. It's a tool and isn't interesting to the average person just playing games.

It should just load up and give you a menu with a brief rundown and instructions.The top has 4 tabs that you can cycle through to show different information. Near the bottom is instructions, basically just hit "A" when you have inserted a disc into the dreamcast and the status bar shows "valid/invalid gd-rom". "X" will trigger a routine to trick the dreamcast into thinking the disc has been removed (you shouldn't need to use it).

Ignore the part about dpad I think it's actually triggers. I can barely remember from last night and I'm away from my laptop at this point.

Just please let me know if after switching disc that something shows up for the low density and high density sections.

Tonight I'll be back and adding more useful things in the this utility and will be updating the builds until it is generating what we/I need.

Thank you anyone who wants to help or is just curious.
Attachments
3_ QUAKE III ARENA.png
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2_QUAKE III ARENA.png
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WINCE_DEV_INTERNAL_1.png
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WingMantis
lithium
Posts: 47

Re: Looking for volunteers! Help us help the community!

Post#2 » Sat Nov 04, 2017 1:03 am

Hmm, what are you thinking about here?

A while back I posted a link to an interview with the Unreal Tournament dev, how he wrote the level loading out in serial format so it would all be contiguous, no seeking.

I have read that some games thrash the drive playing music and loading game data. I was wondering if the CDDA audio tracks could be interleaved with the relevant game data, enough to fill the CD audio buffer then switching back and forth from game data to CDDA (blocks/sectors?) to prevent seeking.

I read one of the game ripping/self boot tutorials you linked in another thread and it didn't sound possible. CDDA info is in one session/mode and data is another.

Could the CDDA be dummied to have the game audio further out on the disc so there is less laser movement?

Could the data audio format be interleaved like I was wondering?

mrneo240
stalker
Posts: 285

Re: Looking for volunteers! Help us help the community!

Post#3 » Sat Nov 04, 2017 2:20 am

WingMantis wrote:Could the CDDA be dummied to have the game audio further out on the disc so there is less laser movement?

Could the data audio format be interleaved like I was wondering?


1st question yes.

no for interleaving. you are bound by cd rom standards

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