[Neo-Geo CD] Art of Fighting - Sound issue

[KamiLordus]

Art of Fighting Neo Geo CD version seems to have broken audio.
The problem occurs after beating the second fight and starting the minigame (bottle smashing, first on the left).
I'm posting the RA save file.
I also tested the AES/MVS version and it seems to work fine.
My version of the game is in bin/cue format. I also tested it on FBNeo and it works fine there.

If a log is needed, I'll post it.

RA 1.22.2 latest nighlty
Geolith 0.41 default settings

save state.zip

[carmiker]

It seems to be a game bug that only happens on the CDZ BIOS. There is a bad DMA request which overflows the CD controller's buffer on CDZ hardware. The question is what the corruption actually sounds like on real CDZ hardware. I am open do doing a "hotfix" like I did for nitd, but it would be nice to know what happens on a real CDZ, which I don't have at the moment.

NeoCD and FB Neo both use a per-game hotfix, while MAME rejects the DMA transfer if it will overflow.

I can't run MAME on my main development machine, so it would be useful to know what happens on MAME too.

MiSTer would be another good test case, just to know how they are handling it.

[KamiLordus]

Thanks for the useful information and a very promising core. The support for chd files compared to FB Neo is a huge plus.
Regarding the issue, I'll definitely try to test another BIOS if I can find one :)
Unfortunately, I've never been able to test the Neo-Geo CD on MAME; it's quite complicated.
However, I would be grateful for a fix for Art of Fighting.

I have another question: have you considered adding sound/music-related options to the core? Something like a low-pass filter, etc.

[carmiker]

I haven't considered post-processing audio filters until now, but it's not a bad idea. I've already done it for my unreleased NES emu, so I might even be able to reuse some of that code.

I'll probably push some kind of core option that marks itself as a hack, but fixes the AoF issue soon.

[KamiLordus]

As for audio filters, RA already has them, but in my tests, they're okay, nothing more. In my opinion, the low-pass filter sounds better on FB Neo (for example).

Returning to the issue, I checked the other BIOSes, and indeed, the "front" and "top" BIOSes don't have this problem, but I managed to reproduce the bug with Universal BIOS 3.3.

[carmiker]

I've pushed the change. The hack is disabled by default, but is listed under "Hacks" in core options as "CD DMA Length Limit".

I'll leave this issue open because there are still questions about what the correct hardware behaviour is.

[KamiLordus]

Now the sound works without a problem. Thanks a lot for the fix.