News: 11 March 2016 - Forum Rules
Current Moderators - DarkSol, KingMike, MathOnNapkins, Azkadellia, Danke

Author Topic: Akumajou densetsu music hack  (Read 726 times)

Gravedigger

  • Newbie
  • *
  • Posts: 3
    • View Profile
Akumajou densetsu music hack
« on: May 30, 2019, 05:03:54 am »
Hello, i'm newer here.

I would like to change the music of the pal version of the castlevania rom 3 on nes by the music of the jap version (vrc6).
In this way I could enjoy the great music of the Japanese version on my console 50hz without slowing down.


Does this hack already exist?
Do you think it would be possible to do that?

Thank you.

Disch

  • Hero Member
  • *****
  • Posts: 2711
  • NES Junkie
    • View Profile
Re: Akumajou densetsu music hack
« Reply #1 on: May 30, 2019, 03:03:17 pm »
Setting aside the music part of this problem... VRC6 doesn't play nice with PAL.


VRC6 uses a CPU cycle IRQ counter that simulates scanlines by counting 113.6667 cycles and treating that as a single scanline.  The problem is, on PAL, scanlines are ~106.5 cycles long.  So EVERYWHERE the game uses IRQs (which, in some places, is 3-4 times a frame), the IRQ counter would need to be readjusted, and it's somewhat possible you might not be able to get the timing exactly right, leaving you with some screen jitter.


So... yes.  It is possible, but it'd be difficult.



Though part of me thinks it might even be easier to retrofit the Japanese version and convert that to PAL rather than trying to convert the PAL version to be VRC6.  But that might be more difficult than I'm imagining, depending on how much the PAL version changes logic-wise.  This is probably where I'd start.  Maybe compare the US version and the PAL version to see what the changes are, then try to migrate those changes over to the VRC6 version.  Then after THAT, go back and try to clean up the IRQ stuff.


But yeah this is a big job.  Probably not one I'd recommend for a newbie, but I've been surprised by newbies before.

Psyklax

  • Hero Member
  • *****
  • Posts: 1019
    • View Profile
    • Psyklax Translations
Re: Akumajou densetsu music hack
« Reply #2 on: May 30, 2019, 03:54:48 pm »
Wait, if I understand you correctly, you want to play Castlevania III, Japanese version, on a PAL NES, with the better sound? That's impossible. Unless I'm very much mistaken (and I doubt it), the US and PAL NES doesn't have any connection through the cartridge slot to the advanced audio chips on Famicom games, which is why the audio was re-done for the US and PAL release. So unless you can hack your actual NES to enable it somehow, then it's not going to happen.

This is without mentioning the endless problems with playing NTSC games on a PAL NES. Seriously, it's not like the SNES where you can literally solder a couple of wires and change to 60hz with the flick of a switch (which I've done). The NES just will not work right with NTSC games, and even if you were somehow able to get a VRC6 gane working, it will not run at the correct speed.

Basically, you're better off using an emulator. Or buying a Famicom. :)

EDIT: Okay, after a quick search, I can see that it's not impossible per se to make a cartridge that lets you hear the VRC6 audio - but that's for the US NES. It still doesn't help with playing it on the PAL NES, and I've yet to see anyone successfully pull that off.
« Last Edit: May 30, 2019, 04:09:43 pm by Psyklax »

Disch

  • Hero Member
  • *****
  • Posts: 2711
  • NES Junkie
    • View Profile
Re: Akumajou densetsu music hack
« Reply #3 on: May 30, 2019, 05:33:05 pm »
I was under the assumption he's either using an emulator or he's got a PAL PowerPak/EverDrive-N8 that he's going to use.  Didn't think we was going to actually gut out a real VRC6 cart.  I think he just wants to run the game on the 50Hz he's used to.

Psyklax

  • Hero Member
  • *****
  • Posts: 1019
    • View Profile
    • Psyklax Translations
Re: Akumajou densetsu music hack
« Reply #4 on: May 30, 2019, 06:08:18 pm »
I was under the assumption he's either using an emulator or he's got a PAL PowerPak/EverDrive-N8 that he's going to use.  Didn't think we was going to actually gut out a real VRC6 cart.  I think he just wants to run the game on the 50Hz he's used to.

If it's an emulator, what's the point? I mean, you can put FCEUX into PAL mode and the graphics will get messed up, but why would you? If it's an EverDrive, the NES still needs to be modified, and even then it's only emulated sound since the EverDrive doesn't have a real VRC6 inside.

So I presume the OP just wanted to take the (slow) PAL version of Castlevania III and add the Famicom music, not realising that to do this is either impossible or would require physical modification of the NES. Sorry. :)

Gravedigger

  • Newbie
  • *
  • Posts: 3
    • View Profile
Re: Akumajou densetsu music hack
« Reply #5 on: May 31, 2019, 03:14:27 am »
Thank you for your answers. i have an everdrive n8 with a nes pal edit. The music of castlevania 3 jap are just perfect. the problem is that the game is slow (50hz). If it is impossible to replace the music of the Pal version with those of the jap version I have another question: can we hack the rom to speed up the game, so that the rom runs at normal speed on my 50hz nes? thank you

Bregalad

  • Hero Member
  • *****
  • Posts: 2626
    • View Profile
Re: Akumajou densetsu music hack
« Reply #6 on: May 31, 2019, 04:39:18 pm »
Thank you for your answers. i have an everdrive n8 with a nes pal edit. The music of castlevania 3 jap are just perfect. the problem is that the game is slow (50hz). If it is impossible to replace the music of the Pal version with those of the jap version I have another question: can we hack the rom to speed up the game, so that the rom runs at normal speed on my 50hz nes? thank you
I already made a patch making Akumajou Densetsu play fine with PAL NES, and this is fine (needs some hardware modification to have the expanstion sound - obviously). The pitch is corrected, but the tempo is a bit slower. You could probably make the tempo faster by changing it in music data, but I tought it wouldn't be worth it.

You can forget about making the game play faster in a 50Hz console. As usual the answer to "is it possible" is yes, but it requires so extensive hacking that it's probably not worth the trouble. Even Konami didn't bother when releasing the official 50Hz version. (very few commercial NES games were PAL-corrected). If playing on 50Hz is that much of a problem, you should either play on an imported console or an emulated version.$

Quote
Setting aside the music part of this problem... VRC6 doesn't play nice with PAL.


VRC6 uses a CPU cycle IRQ counter that simulates scanlines by counting 113.6667 cycles and treating that as a single scanline.  The problem is, on PAL, scanlines are ~106.5 cycles long.  So EVERYWHERE the game uses IRQs (which, in some places, is 3-4 times a frame), the IRQ counter would need to be readjusted, and it's somewhat possible you might not be able to get the timing exactly right, leaving you with some screen jitter.
My hack does it just fine :p

Gravedigger

  • Newbie
  • *
  • Posts: 3
    • View Profile
Re: Akumajou densetsu music hack
« Reply #7 on: June 01, 2019, 11:19:26 am »
Yes I already tried the "Pal fix" it works very well, but the game is really too slow compared to the original.