ADPCM-B Playback Demo - Page 1

After a few days of on and off work, I've hacked up a little interactive demo that lets you play back an ADPCM-B sample and change various parameters:



The demo can be downloaded here: http://ajworld.net/neogeodev/examples/adpcmb_demo.zip
ROMs and source code are included.

Edit: Major update!
I figured out what was wrong with my Z80 code... stupid 6502 habits creeping in for immediates.
Try version 3 at http://ajworld.net/neogeodev/examples/adpcmb_demo-v3.zip

Hello

Good work
Have you doing an CD version ? with an Iso ?

Unfortunately, Neo-Geo CD does not allow for ADPCM-B playback, otherwise I would've.

Good Job again, Freem !!!

you said 'Unfortunately, Neo-Geo CD does not allow for ADPCM-B playback, otherwise I would've'

Informations found in the NG dev WIKI :
https://wiki.neogeodev.org/index.php?title=CD1_hardware CD1(front loading)-> have an real YM2610 sound processor..

https://wiki.neogeodev.org/index.php?title=CD2_hardware CD2(top loading) -> have NEO-YSA (It regroups the YM2610->use emulation?, NEO-VOC and NEO-SUD chips)

https://wiki.neogeodev.org/index.php?title=CDZ -> have NEO-YSA2 is included in the CDZ (Contains a YM2610 and Z80 CPU)


Freem remember you -> KUK have this Real hard: CD1 and CDZ (Aymeric, could you confirm ?)
-> If That's write, kuk can may be tested your 'adpcmb_demo' on his CD1 console? -> Then we will be fixed, is'not it?


ABOUT NEO GEO CD >>problem with ADPCM-B feature
"Actual events leading to this discovery.Fun fact: Neo Geo CD does not support ADPCM-B"

-> If this information is real (Not a joke), It's not realy funny I think ...

https://wiki.neogeodev.org/index.php?title=Special:Contributions/Hpman ->
current 00:33, 17 March 2014 contrib:

DARTH VADER said: 'You won't be able to fit your database in this bios'(*)...'I'll just downsample the PCM data'...'NGCD has no ADPCM-B'!

(*)Laurent/HPMAN -> could you provide additional information regarding this problem->
Are the 3 CD hardware versions concerned ? (even CD1 who have a real YM2610!)

Last question, this problem can be fix in the futur, by just adding routines in BIOS (or Homebrew BIOS, like The NeoOpenbios project) or
stuff like that, by 'MODDING' /Additional Hardware board ?

Regards, Fred/FRONT!

yes il have all the hard neo geo CD
and the CD 1 and CDZ are on the top of my TV

I didn't realize that the first version of the CD console had a real YM2610 in it. That might change things... Luckily, it won't take too much effort to create a CD version.

I still get the sinking feeling that SNK wanted developers to use the CD-DA channel instead of ADPCM-B though.

Edit: made the necessary changes to create a CD version... Most emulators do nothing, but oddly enough, Raine gives a low clicking noise on playback.
ISO can be downloaded here; hopefully it will burn properly. I used the instructions from the ISO generation page on the wiki to make the image, so hopefully that will work.

i try to test it this week end

Hello

So i have the menu like in your screenshoot, but i have no song of the sample it is normal ?

I found a post by Razoola saying he wasn't able to play ADPCM-B on Neo-Geo CD, so it's very highly likely this will only work on cart systems.

There is a real YM2612 in some Neo CDs but the ADPCM-B bus isn't wired (open pins).

donc on pourrait le rajouter ?
(note une nouvelle idée qui sert a rien)

It's come to my attention that this demo isn't exactly perfect when it comes to playback... Apparently you need to change a variable on each of the items before the sound engine will let you play on some emulators, and on others (and probably real hardware), it won't work at all. I'm trying to look into this, but since I suck at Z80, it's probably going to take a while.

Edit: for some reason, the driver is being sent to 0x000C as its entry point instead of 0x0000 and I don't know why.
Edit 2: the demo works in my fork of MAME/MESS, but not the current mainline binaries... I can't think of why this is, as I haven't changed anything related to the sound.

double posting only because I found out what the problem was and have released a fixed version:
http://ajworld.net/neogeodev/examples/adpcmb_demo-v3.zip

(The problem was I was treating immediates like they were in 6502 (e.g. #num) instead of just num by itself. Sucking a bit less at Z80, but still a lot to learn.)